Quenching distortion in AISI E52100

Hans Kellner

Master of Science Thesis MH210X

Materials Science and Engineering, KTH

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Abstract Heat treatment of different steel products have existed for thousands of years. It has always been an important tool to get the microstructure and resulting properties such as hardness and case hardness and it is even more important today than ever before. This project concentrated on the quenching process and means to decrease the distortion caused by this process. The effect of different oils, temperatures, agitation and if gas quenching could give better results were investigated. The results showed that Miller´s 75 quench oil was better than Park´s 420 at slow agitation and that the viscosity of the oils influenced how much changes in agitation speed and oil temperature affected the distortion. It also shows that gas quenching is an alternative to oil quenching if the microstructure can be improved. Otherwise using Miller´s 75 with low agitation in the Surface combustion furnace will give best results.

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Sammanfattning Värmebehandling av olika järn produkter har existerat i tusentals år. Det har alltid varit ett viktigt redskap för att få dem mikrostruktur och resulterande egenskaper så som hårdhet och det är ännu viktigare idag än tidigare. Detta projekt koncentrerade på härdningsprocessen och möjligheterna att minska deformationen orsakad av denna process. Effekten av olika oljor, temperaturer, omrörning och om gas är ett alternativ var undersökt. Resultatet visar att Miller´s75 härdnings olja var bättre än Park´s 420 vid långsam omrörning och att viskositeten av oljorna påverkar hur mycket förändringar i temperaturen och omrörningen ändrar deformationen. Det visar också att gaser är ett alternative till olja vid härdningen om mikrostrukturen kan förbättras. Annars så gav Miller´s 75 olja med långsam omrörning i surface combustion´s ugn det bästa resultatet.

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Abbreviations

HPGQ High Pressure Gas Quenching

LOM Light Optical Microscope

Troostite Old name for fine perlite

USL Upper Specified Limit

LSL Lower Specified Limit

SL Specified Limit

UCL Upper Control Limit

LCL Lower Control Limit

ALD The company “ALD Thermal Treatment”

Ms Temperature when martensitic transformation starts

M50 Temperature when martensitic transformation has reached 50%

AISI The steel standard specified by American and Steel Institute

BCC Body Centered Cubic

BCT Body Centered Tetragonal

FCC Face Centered Cubic

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Table of Contents Abstract ...... 3 Sammanfattning ...... 5 Abbreviations ...... 7 Introduction ...... 11 processes ...... 11 Distortion ...... 11 Quenching process ...... 12 Oil Quenching ...... 15 Gas Quenching ...... 17 AISI E52100 ...... 18 Objective ...... 19 Experiments ...... 20 Results and discussion ...... 23 Conclusions ...... 33 Future work ...... 34 Acknowledgements ...... 35 Bibliography ...... 36 Appendix ...... 38

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Introduction

Heat treating processes There are many different processes that fall under heat treating. Two processes where the material is heated to a given temperature and then cooled down is normalizing and . For the normalizing process the metal is heated to approximately 100°F (55 °C) above the austenitizing temperature to get a uniform size of the grains and uniform composition. It is then cooled down at an appropriate speed. Then there is tempering where the temperature is held below the austenitizing temperature and that is aimed to increase the ductility and toughness. Both of these methods theoretically fall under whose broader definition only says that the material is heated up to and held at a suitable temperature and then cooled down at a suitable speed. Both the normalizing process and the tempering process can be used to relieve stress in the material but tempering is the most used one. While the tempering can cause precipitations the normalizing will give again and you would have to quench it once more (1).

Heat treating processes also include different processes such as quenching, and . Quenching can be used to get both surface hardness and through hardness depending on how fast the material is cooled down throughout the part. Faster cooling give while slower cooling can give ferrite, bainite and perlite. But usually when quenching is used you want to get martensite. Carburizing and carbonitriding on the other hand can only be used to get a hard surface layer and is done by heating up the material in a carbon rich atmosphere or with a powder on the material (1).

When steel is quenched to get martensite you will get retained austenite in almost all cases. To transform this to martensite the material can be cold or cryogenic treated where the steel is cooled down to around -120°F (-84°C) or -310°F (-190°C) (1).

These processes are put together in different ways and with different parameters to get the wanted effect on the material. Most of the time this means to get as little distortion as possible and the right microstructure.

Distortion When a material is quenched there are three fields that will change. These are the thermal field, the metallurgical field and the mechanical field that distortion falls under (2).

The distortion occurring during quenching can be divided into two main parts, shape distortion and size distortion. Shape distortion is when the product twist, bend or warp out of shape while size distortion keeps the form but the measurements change due to changing volume (3) (4).

There are three main reasons for distortion during quenching. First there are microstructure changes that will induce transformation kinetics and transformation plastics. This will give slightly different

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volumes when the phases change resulting in internal stress that when it exceeds the yield strength causes distortion of the part. Work on simulating this has been done by e.g. Seok-Jae et al. (5) using the FEM software ABAQUS. Their simulation of distortion in AISI 5120 during quenching was relatively close to the actual result from quenching. The second reason is gradients in the materials thermal field that will cause different expansion coefficients with stress as a result. Last of the three main reasons is residual stresses that can distort the material when the temperature is raised and the yield strength decrease. The residual stresses are mainly due to the machining of the parts and will vary somewhat during the lifetime of the tools used to produce the parts (3). Any distortion occurring will originate from one or more of these reasons. In Figure 1 the relationships between the three reasons described above and several others are shown.

Figure 1. The relationship between the different fields and what affects them during the quenching process (2).

In the study by Ashok et al. (2) it was concluded that the material properties that affect the residual stresses and distortion are the thermal conductivity, the Ms temperature and the shear modulus.

Surm et al. (6) studied different causes for distortion and roundness deformation on bearing rings made of AISI E52100 and concluded that the stacking geometry of the parts during the quenching was important. As this affects the flow of the quenching media and therefore can cause temperature gradients this result is to be expected. They also concluded that the austenitizing temperature, soaking time and pre-heating temperature did not affect the distortion (6).

Quenching process There exists a multitude of quenching methods e.g. air quenching, oil quenching, water quenching, gas quenching, spray quenching, fog quenching and (1). As different quenching media have different heat transfer coefficients they will cool down the material differently and give different thermal fields. With a slower cooling the thermal fields in the material will not differ that much resulting in less deformation. Lijun et al. (7) compared different quenching media and got the cooling curves seen in Figure 2.

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Figure 2. Cooling curves for different quenching media both from the surface and center of the tested part (7).

These curves are for both the center and the surface of the part and show a temperature difference between them. According to Figure 2, nitrogen gives the slowest cooling while oil is the next slowest. It is also these two that have the smallest temperature difference between the surface and the center. This is easier seen in Figure 3.

Figure 3. Temperature difference between the center and surface of the part as a function of internal temperature (7).

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Together with Kessler et al. (8) it confirms that the cooling curve for gas quenching is slower and has less difference in temperature than oil quenching and therefore lower distortion. The two quenching methods considered in this project will therefore be the oil quenching and gas quenching methods. Both of these methods work along the same basic principle for the quenching. After heating the parts up to 1500-1600°F (815-870°C) they are rapidly cooled down with the help of the quenching media.

To get as little distortion as possible and at the same time get the targeted microstructure and hardness there are several things that need to be considered. These are the steel composition and , geometry of the part, machining process, type of quenching medium, temperature of quenchant, agitation and condition of the quenchant (1).

Of these parameters there are three that are decided before the quenching process. These are the steel composition, geometry and tooling. The steel composition depends on what you will use the product for when it is done and the same goes for the geometry of the part. These parameters will have to be considered when the quenching process is set up the first time but do not change over time. Next, there is machining, that is, how the part gets the right shape. Different machining processes give different amount of residual stresses and even the same machining process can give a varying result over the lifetime of the tool. This is not something you will always know for production purposes, which is why it is something that is hard to account for every time. The most common thing is therefore to assume the difference in the residual stresses under a tool life is negligible. It is then possible to count it as a constant parameter in the same way as the material composition and the geometry of the part.

Then there are the parameters that you can change during the quenching process. First there is the quenching medium. This is very important as different media have different cooling curves, see Figure 1, and will consequently give different properties to the material. This is especially true for oil quenching where there are three different phases during the quenching. These three phases are the vapor phase when you have a uniform layer of vapor on the surface, the boiling phase where the quenching medium boils on the surface and the convection phase where heat is dissipated through convection of the medium only, see Figure 4.

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Figure 4. The three stages during oil quenching. The vapor stage, vapor layer on the surface. The boiling state, bubbles of gas is formed on the surface i.e. boiling. The convective stage when the heat transport occurs through convection (9).

With different media different phases can be promoted changing the cooling curve. For the gas quenching process you only have the convection stage. Then there is the temperature of the quenching media. This affects the quenching speed and for the oil it also controls the life of the oil as well as the viscosity. The agitation helps to maintain a uniform temperature in the quenching bath. It helps to shorten the vapor phase time and raise the maximum cooling rate which decrease the quenching time. The condition of the quenching medium includes degradation of the oil or contaminations in it as well as in the gas. Oxidation of the mineral oil and thermal degradation of polymers are examples of how the oil change during usage and why it needs to be checked form time to time. It is also possible to get contaminations in the quenching medium such as water in the oil or a different gas than the wanted one in the gas quenching (1).

Oil Quenching From the time that oil quenching first appeared and metals were submerged in a bucket of oil the technique have evolved considerably. The goal has been to improve the surface finish, microstructure and distortion. In modern furnaces it is possible to change the agitation during a quenching process thus enabling a much better possibility to control how long each of the three stages of the quenching process is. It’s then possible to decrease and control the distortion to a higher degree compared to when only a single agitation mode could be used or when no agitation is possible. It is also important to control how the oil flows over the parts. This can be done by changing either the loading geometry or how the oil flows around the parts (10).

The oil itself is also very important as different oils have different cooling curves and is made for materials with different ability to quench harden. Even oils that would work perfectly theoretically or in tests with only a few pieces may show slightly different cooling curves throughout the load if the furnaces are packed with more parts or if the smaller parts are replaced by one big part. It is therefore very important to keep track of how the distortion and hardness change throughout the load (11) (12).

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The oil will also change properties with different contaminations and age. A list of the most common contaminations found in quenching oils is given below:

 Water  Hydraulic fluid  Temperature  Oxidation  Soot  Salt

The presence of hydraulic fluid, soot, salts or water increases the maximum cooling rate while oxidation decreases the maximum cooling rate and the temperature of maximum cooling by increasing the viscosity of the quench oil. An increased temperature will increases the maximum cooling rate of the oil and the temperature of maximum cooling rate as the viscosity is decreased and as well as the heat transfer. Salts and hydraulic fluids increase the temperature of maximum cooling by two different mechanisms. Salt provides additional sites for bubble formation, causing the temperature of maximum cooling to increase, while the presence of hydraulic fluid reduces the viscosity of the quench oil and enhances bubble formation because of the different boiling points of oil and hydraulic fluid. Water decreases the temperature of maximum cooling, which in turn cause increased distortion, see Fel! Hittar inte referenskälla.. It is also a fire and explosion hazard (13).

Figure 5. The effect of different contaminations in quenching oils (13).

It is therefore very important to keep track of any changes and contaminations in the oil.

Depending on what you want the oil to be able to do different additives is added to it and has to added again once in a while as their effects deteriorate with time. It can be for faster cooling, antifoaming,

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oxidation inhibitors and other functions. There are several ways to protect the oil from degrading and the most important one is to use the oil in the intended temperature range as it oxidizes faster at elevated temperatures. For this purpose it’s possible to use a protective atmosphere or vacuum as well. Vacuum will result in less water in the oil since it will evaporate and it will prevent formation of ash to a certain degree (14).

Gas Quenching There is a wide range of different gas quenching furnaces. They can have one or two chambers, operate under low or high pressure, different gases as quenching media and different possibilities for agitation and control of the gas flow.

A quenching furnace with only one chamber will only allow gas as quenching medium while a two chamber furnace can allow for switching between oil and gas. But If only gas will be used then a one chamber furnace is enough and a two chamber furnace is just excessive cost (15).

The difference in pressure during the quenching will affect the thermal conductivity. A higher gas pressure will give a higher thermal conductivity as the gas will be denser and therefore able to transfer more heat. For the low pressure the opposite is true. In modern furnaces you can change the gas pressure during the quenching and so affect the cooling effect (16).

Depending on how many pieces that you want to quench at the same time the agitation flow control vary. If there is only one or a few pieces that is quenched at the same time it is possible to be much more exact in how the flow is. Especially for single pieces where multiple nozzles can be put up to direct the flow over the piece in a very exact manner. This was demonstrated by Schuettenberg et al. (17), (18) using nozzles to control the flow to specific areas of the part minimizing and controlling the distortion. In both cases the distortion and the flow were computer modeled before being confirmed with experiments. Unfortunately this method is not possible to implement in a normal quenching furnace where you put in a load of many parts at once and the parts can vary in size and geometry. That makes it impossible to have stationary nozzles that control the gas flow on every piece. Instead you have to be content with being able to control the flow more generally. Existing commercial ways is able to change the general flow so it flows from top to bottom or reversed. It is also possible to change the speed of the flow during the quenching. All this can be used to control the cooling curve (17) (18).

The risk of contaminations is lower using gas quenching since an inert gas is used. The one contamination that do occur and that can cause a problem is small quantities of other gases than the specific gas or gas mix that is intended for the quenching. It could then react with the material of the product or change the properties of the gas (1).

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AISI E52100 The AISI E52100 is a high carbon, chromium alloyed steel that is easy to machine before heat treatment but that can reach relatively high hardness and abrasion resistance after heat treatment. It is a good material when great wear resistance is needed (19) as is the case for parts in automotive engines. The Isothermal transformation diagram that shows how fast you need to quench the material to avoid other phases than martensite is in Figure 6.

Figure 6. The Isothermal Transformation diagram for AISI E52100 (1).

For normal hardening the material should be austenitized at 1555°F (845°C) but if distortions are an issue it can be done at 1500°F (815°C) (1).

When the temperature reach Ms the cooling rate should be lower to allow for an even temperature change throughout the whole part. In that way there is less induced stresses from thermal fields and from changes in microstructure.

The change in microstructure during the austenite to martensite transformation induces a volume increase as the BCT crystal structure has a lower density than the austenite’s FCC structure. Even if you get ferrite instead of martensite a volume increase will take place even if it is less than for martensite. This is due to the BCC structure that has a density between the BCT and FCC crystal structure. These volume changes are true for all steel with some minor differences in the exact volume changes due to the alloying elements.

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Objective The main objective of the present work was to build up the understanding of how AISI E52100 will behave during different quenching parameters and quenching methods and then be able to decrease the distortion and learn how to better control the remaining distortion

Several experiments to gather information have been performed both at Cummins and at other companies. The focus has been on oil quenching as that is the current method used by Cummins and testing on how the different agitation rates will affect the distortion has been performed. Each company also uses different oils and will therefore run the test at different temperatures. To see how the temperature affects the distortion, test with different temperatures was performed at Cummins.

Two tests were performed in a HPGQ furnace to see how that compares to the distortion from oil quenching and if it could be a viable option.

The parts placement in the load was also analyzed as well as the thread tempering’s effect on the distortion.

This project will also form the basis for a database that will continue to be filled out with information from normal production and other test as a support of other long term projects that need information that reach over a whole year and not just a few months to be of value. One example is how the oil condition affects the distortion. This is important but the oil will not change during the short interval between the two tests at every facility and is therefore not possible to consider in this project.

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Experiments All experiments were done with a full load where 27 parts were mere measured before and the remaining parts were scrap parts to simulate reality. To be able to see how the distortion differed throughout the load and as it consisted of 3 layers 9 different zones were picked, see Figure 7, and 3 parts that were measured beforehand with Zeiss Gage Max CMM were put in each zone. The exceptions to this are the two tests done at ALD where the top blown and reverse blown had 40 and 37 parts each in the test. The exact zones for those parts are not known.

Figure 7. The way the parts were distributed in the three layers of the load. The front is the part loaded first into the furnace.

For every test the parts were austenitized first at a temperature of 1525 °F in the heat chamber. After they were quenched they followed the normal route with temper (325°F), deep freeze (-150°F), temper (425°F) and thread temper process after the quenching. This part was the same for all tests except number 7. That test was left in the first tempering cycle much longer than the others by a mistake.

The tests were performed at 3 different companies and in both oil and gas quenching furnaces with different parameters different parameters according to

Table 1. The furnaces that are used at Cummins and Nitrex are of the same model and manufacturer. The top and reverse blown agitation for the ALD gas quench means that the cold gas flows through the top to the bottom of the load. Reverse blown means just that. The flow comes from the bottom and going out the top.

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Table 1. The parameters for each test and where it was done as well as the furnace.

Test Alternative Company Furnace Oil/gas Agitation Temperature/ Name pressure

1 M75S190 Nitrex Surface combustion, two Miller’s Slow 190°F chamber vacuum quench oil 75

2 M75F190 Nitrex Surface combustion, two Miller’s Fast 190°F chamber vacuum quench oil 75

3 H18BB ALD Module Therm Furnace Helium Bottom 18 bar blown

4 H18TB ALD Module Therm Furnace Helium Top blown 18 bar

5 P420S190 Cummins Surface combustion, two Park’s 420 Slow 190°F chamber vacuum quench oil

6 P420F190 Cummins Surface combustion, two Park’s 420 Fast 190°F chamber vacuum quench oil

7 P420S210 Cummins Surface combustion, two Park’s 420 Slow 210°F chamber vacuum quench oil

8 P420F210 Cummins Surface combustion, two Park’s 420 Fast 210°F chamber vacuum quench oil

9 P420S190P Cummins Hayes, HPO-202436 Park’s 420 Slow 190 °F quench oil

The production is currently done in the Hayes furnace while all other oil quenching tests were done in the Surface combustion furnace. The main difference between these two furnaces is that the one used for production does not have any water cooling of the oil during quenching which the Surface Combustions furnace has.

Nitrex and Cummins use two different oils that have different cooling curves. The actual curves will be looked at from oil samples during the experiment. Something that will not be looked at is the viscosity

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and instead we will use the values for the new oils. The viscosities for the oils are 15 cSt for Miller 75 (at 40 °F) and 54 cSt for Park 420 (at 100 °F). As the viscosity decrease with a raised temperature the 420 quench oil have a much higher viscosity than the 75 quench oil.

After the thread temper the parts were measured in the Zeiss Gage Max CMM (exception test 3, 4 and 8 that were measured before as well) and one part from the middle zone were analyzed regarding the hardness and microstructure to see that they conformed to the requirements Cummins have. For this analysis an Arc Sparc (Spectro Max) model LMM04 was used for the Rockwell hardness measurements and a LOM for the microstructure.

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Results and discussion The result form the measurement of the cooling curves for the used oils is seen in Figure 8. It shows that the 420 quench oil starts cooling earlier but then slow down earlier as well compared to quench oil 75. It is first towards the very end that it looks like they have the same cooling speed or a slightly slower one for the 75 quench oil.

Figure 8. To the left it is the cooling curve for the used Miller's 75 from Nitrex vs new 420. To the right it is Cummins used 420 vs new 420. Red represent new 420, blue is used 420 and green is used 75. They were tested at 190 °F and with no agitation.

More exact values at a few certain times on the cooling speed and time to reach different temperatures is in Table 2. These values agree with the previous figure. While the 75 quench oil’s cooling speed is faster at 572 °F it is not by much and it will change at lower temperatures. If these values are compared to the TTT diagram in Figure 6 it is clear that both oils will be cooling the material too slow to avoid the phase transformations completely. But as this is done with no agitation the cooling curve of the oils will change for the tests as agitation is used in them. As a result the material is cooled down fast enough so that no phase transformations occur.

Table 2. Time to reach specific temperatures and cooling speed for the oils used during quenching at the quality they were in. *There are no value for this, **The test sample did not come down to this temperature in 60 seconds.

Temperature Time to reach the temperature (Parker/Miller) Cooling speed (Parker/Miller) 1112 °F 7.375/8.625 sec * 752 °F 14.750/11.625 sec * 572 °F * 8.49/9.18°F sec 392 °F **/50.250 sec *

While a lot of different measurements were performed for each part only 10 will be considered in this project. These measurements were divided with two on the OD and eight on the inside of the bore, see Figure 9.

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Figure 9. The barrel used for the tests and where the measurements were.

First there is the OD that had 2 measurements for each part. The distortion for each point and test is seen in Figure 10. This data clearly shows that the distortion is bigger at measuring point H2 than at H1 which is closer to the thicker part of the pump tappet barrel. As this is the case to a varying degree for each test the only influencing factor should be the geometry of the barrel.

While the USL is 40 µm and only test 3 passes that, all tests are better than test 9 that represent the production run. The tapering for test 9 is also as big as or bigger than any other test.

Distortion At The OD For Each Test 0.07

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0 0 B B 0 0 0 0 P 9 9 B 9 9 1 1 0 1 1 8 T 1 1 2 2 9 S F 1 8 S F S F 1 5 5 1 0 0 0 0 S 7 7 H H 2 2 2 2 0 4 4 4 4 2 M M P P P P 4 P

Figure 10. The distortion at each measurement point on the OD for each test.

To confirm the graph the Cp and Cpk values were calculated for the tests giving the values seen in Table 3. As the Cp and Cpk is a measurement used to indicate process capability or how the measurements are

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considering the SL they will indicate if the measurements are good or bad considering the SL. Cp is a measurement of how centered the measurements are. Measurements closer together give a higher value. Cpk shows how close the measurements are to the SL and a higher value is better here as well. They were calculated in Minitab by creating the six pack figures found in appendix 1.

If we look at the OD values only test 2-4 would pass Cummins requirement of 1.67 as a value for Cp and none for Cpk. But if the values are compared to test 9 all are better which confirms Figure 10.

Table 3. The Cp and Cpk values for the bore and OD from each test.

Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Cp (bore) 1.10 0.93 1.88 1.24 0.96 0.99 0.98 1.02 1.00 Cpk (bore) 1.09 0.78 1.80 1.17 0.69 0.71 0.74 0.75 0.89 Cp (OD) 1.47 2.29 2.46 2.92 1.33 1.22 1.39 1.28 1.19 Cpk (OD) 0.11 0.17 0.58 0.52 0.33 0.22 0.14 0.25 -0.06

While the Cp and Cpk values for the OD did not fulfill the requirement for any test there is one case for the bore where both the Cp and Cpk requirements are fulfilled. It is test 3 that succeeds while every other test fails on both values. Of the other test it is number 4 that is closest followed by number 1. The test done in the Surface Combustion furnace all has very similar results with no big difference visible in the values. Together with the fact that the average distortion for these tests is very close together as seen in Figure 11 the results point towards that there is very small differences in distortion between those tests. The distortion curve for the bore also shows that test 3 and 4 is best followed by the tests from Nitrex. Between the Nitrex tests there is also a bigger change in distortion when the agitation is changed. This is due to the lower viscosity of the 75 quench oil compared to the 420 quench oil making it much easier to put the oil into motion. All tests also show a similar shape on the distortion curve to each other indicating that the shape depends on the geometry of the part and not something else. It is at the thickest part that the biggest distortion is taking place and this is in agreement with the theoretical knowledge that a thicker material has a bigger temperature gradient between the middle and the edges giving more distortion.

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Average Distortion For All Tests Over Inner Bore

0.02 Variable M75S190 0.01 M75F190 H18BB H18TB 0.00 P420S190

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Figure 11. Average distortion of the bore for all tests.

Something that is very important but isn’t seen in this diagram or in the Cp values is the tapering. This is instead shown in Figure 12-Figure 16. The mean distortion and tapering for the current production. For test 1 and 2 the biggest tapering are around point A4 and A5. The overall tapering as well as distortion is also less for test 2. This means that for this oil and temperature slow agitation is better than fast. When the speed is increased the oil is moved around too much causing the material to cool down too fast and giving more distortion. The temperature in the oil bath becomes more uneven as well for the faster agitation causing more difference in distortion between the parts.

Mean Distortion And 95 Percentile Box For Bore Measurements M75S190 Mean Distortion And 95 Percentile Box For Bore Measurements M75F190

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Figure 12. The mean distortion and tapering for test 1 and 2 at each measurement point.

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For test 3 and 4 the tapering is seen in Figure 13. These graphs show a clear difference between the bottom blown and top blown tests with more distortion and tapering under the threads for the top blown. One explanation to this could be that the air coming up from the bottom hits the thinner area first, gets warmed up a little bit before it hits the thicker part giving a more even temperature and slower cooling. This theory agree with the fact that when the gas hit the top first you get less distortion at the thinner part compared to the bottom blown. To really confirm this theory it should be a difference between the different layers of the load but as there is no information on where the parts were, this is not something that can be checked and unfortunately the theory cannot be confirmed.

Mean Distortion And 95 Percentile Box For Bore Measurements H18BB Mean Distortion And 95 Percentile Box For Bore Measurements H18TB

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Figure 13. The mean distortion and tapering for test 3 and 4 at each measurement point.

The distortion for test 5-8 looked very similar to each other in Figure 11 and the graphs in Figure 14 and Figure 15 shows that the tapering is very similar as well. There is a slight decrease in tapering and distortion when the agitation is fast which tells us that the temperature differences decrease. It is due to the high viscosity that the difference is much less than for the tests using Miller´s 75. The raise in temperature does not affect the results and give almost exactly the same result between the 190 ˚F and 210 ˚F. As the difference in distortion and tapering is very small for these four tests it would be possible to change the print so that instead of reducing the distortion you re-center the part allowing for the distortion so that the final measurements aren’t outside the limits. Of course it would be better to change to another process instead of these that have less distortion.

Mean Distortion And 95 Percentile Box For Bore Measurements P420S190 Mean Distortion And 95 Percentile Box For Bore Measurements P420F190

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Figure 14. The mean distortion and tapering for test 5 and 6 at each measurement point.

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Mean Distortion And 95 Percentile Box For Bore Measurements P420S210 Mean Distortion and 95 Percentile Box For Bore Measurements P420F210

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A1 A2 A3 A4 A5 A6 A7 A8 A1 A2 A3 A4 A5 A6 A7 A8

Figure 15. The mean distortion and tapering for test 7 and 8 at each measurement point.

For the current production process there is less tapering and distortion, see Figure 16, than in the other tests done at Cummins. Or rather, the distortion is more centered letting all of the values get inside the +/- 50 μm limit. The only tests that have less distortion than the production are the slow agitation test at Nitrex and the gas quenching tests. It is therefore only these tests that are better than the production run when both the OD and bore distortion are considered.

Mean Distortion and 95 Percentile Box For Bore Measurements P420S190P

0.02

0.00

)

m

m

(

n o

i -0.02

t

r

o

t

s

i D -0.04

-0.06

A1 A2 A3 A4 A5 A6 A7 A8

Figure 16. The mean distortion and tapering for the current production.

Among all the tests there were tapering. This is something you want to avoid in order to predict where the distortion will occur. As the tapering could depend on uneven temperature in the furnaces the

28

distortion in each zone were studied for each tests. If a connection between the zones in the furnace and the distortion tapering exist it can be fixed by changing the agitation or modify the furnace.

In Figure 17 the zone distortion for test 1 is shown. For this test there are 2 zones that are standing out from the others. It is zone 1 and 6 which is both in the lower layer on the left side seen from the load front. It is therefore a good possibility that this depended on uneven flow of the oil in the furnace. To confirm this, the same tendency would have to take place in test 2.

Distortion Individual Zones M75S190

0.02 Variable Zone 1 Zone 2 Zone 3 0.01 Zone 4 Zone 5 Zone 6 ) 0.00 Zone 7

m Zone 8

m (

Zone 9

n o

i -0.01

t

r

o

t

s i

D -0.02

-0.03

-0.04 1 2 3 4 5 6 7 8

Figure 17. Mean distortion for each of the individual zones for test 1.

Compared to test 1 the zones distortion in test 2 more evenly spread out, see Figure 18. The zones that are standing out from the others are 3 zones different from those in test 3. It is therefore impossible to confirm if the distortion depends on the zones or not. At the same time, the faster agitation for test 2 may cause a different flow in the tank. That also makes it impossible to disregard the possibility without further tests done at the slow agitation.

29

Distortion Individual Zones M75F190

0.02 Variable Zone 1 Zone 2 0.01 Zone 3 Zone 4 0.00 Zone 5 Zone 6

) Zone 7

m -0.01 Zone 8

m (

Zone 9

n o

i -0.02

t

r

o

t s

i -0.03 D

-0.04

-0.05

-0.06 1 2 3 4 5 6 7 8

Figure 18. Mean distortion for each of the individual zones for test 2.

For the tests performed at Cummins the zone distortion looked very similar to the example in Figure 19 where there are no discernible connection between the zones and the tapering. This is true for both the Surface combustion furnace and Hayes furnace.

Distortion Individual Zones P420F190

Variable Zone 1 0.00 Zone 2 Zone 3 Zone 4 -0.01 Zone 5 Zone 6

) Zone 7 m Zone 8

m -0.02 (

Zone 9

n

o

i t

r -0.03

o

t

s

i D -0.04

-0.05

-0.06 1 2 3 4 5 6 7 8

Figure 19. Mean distortion for each of the individual zones for test 6.

30

In all the figures describing the bore distortion the thread tempering distortion has been included as well. To see how just the thread tempering added to the distortion some tests were measured before the thread tempering as well. Figure 20 shows how the distortion looks for the two gas quenching tests. The only significant distortions are at measurement point A1 and A2 for both tests. This is no surprise since these points are under the threads that are induction tempered while the other points are outside the heated part. The reason the for the distortion is that when the induction tempering takes place the temperature is not raised fast enough to just raise it in the threads. Instead the temperature is raised all the way to the bore and to a higher temperature than the last tempering indicating as the steel get a blue color during the tempering that is creeping towards the core. That color represents a temperature of about 550-600 ˚F and are much higher than the temperature of the last tempering (20). This cause stress relaxation in the material that gives the distortion observed.

Distortion From Thread Tempering H18BB Distortion From Thread Tempering H18TB 0.005 0.005

0.000 0.000

) )

m m

m m

( (

-0.005 -0.005

n n

o o

i i

t t

r r

o o

t t

s s

i i D D -0.010 -0.010

-0.015 -0.015

A1 A2 A3 A4 A5 A6 A7 A8 A1 A2 A3 A4 A5 A6 A7 A8

Figure 20. Thread tempering distortion for the gas quenching tests.

In Figure 21 the distortion for test 8 and 9 is shown and it is very similar to the gas quenching tests. This indicates that independent of what method used to quench the product the thread tempering will be the same. If the thread tempering step were removed a significant portion of the distortion would disappear and all of the test would fall inside the distortion limits for the bore. The best way to do this would be to try to change to a more powerful source of power for the induction heating. That would allow for a faster raise in temperature during the thread tempering causing less heating of the core. If only the threads could be heated there would be no significant distortion in the core.

31

Distortion From Thread Tempering P420F210 Distortion From Thread Tempering P420S190P 0.005 0.005

0.000 0.000

) )

m m

m m

( (

-0.005 -0.005

n n

o o

i i

t t

r r

o o

t t

s s

i i D D -0.010 -0.010

-0.015 -0.015

A1 A2 A3 A4 A5 A6 A7 A8 A1 A2 A3 A4 A5 A6 A7 A8

Figure 21. Thread tempering distortion for test 8 and 9.

While the goal is to limit and control the distortion the most important thing is to keep the required microstructure and properties for the pump tappet barrel. Whether the parts from the tests fulfill the hardness requirement and what microstructure they had is shown in Table 4. All parts fulfill the prints requirement except test 3 and 4 from ALD that had troostite in the microstructure. While the amount is small enough that it does not affect the hardness and would pass a test if it were a single sample from production it is more important in this case. As no confirmation test has been done there is no way to know if this is normal or if it is more or less than usually. That means that even small variations may cause troostite in the material which is unwanted and can lower the hardness. Therefore it would be best to change to oil M75S190 to get a decrease in distortion and still keep an acceptable microstructure.

Table 4. Information about how the samples hardness and microstructure is compared to the prints requirement. The amount of retained austenite found during the two measurements. The testing was done on a part from zone 5.

Print Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8 Test 9 Micro- Marten Marten- Marten Marten- Marten- Marten- Marten- Marten- Marten- Marten- structure -site site -site site, site, site site site site site troostite troostite Hardness 53-62 Follows Follows Follows Follows Follows Follows Follows Follows Follows HRc the the the print the print the the the the the print print print print print print print Retained <5% 1.16% 2.67% 2.36% 3.60% 0.99% 1.72% 0.84% 0.67% 1.45% Austenite 1.15% 1.99% 1.92% 3.43% 0.79% 1.42% 0.43% 1.05%

32

Conclusions

. All tests gave less distortion than the production run at the OD.

. Changing agitation speed or temperature does not result in a significant difference in distortion at Cummins.

. Lower viscosity of the oil gives less distortion at the right speed.

. There is no discernible connection between the different heating zones the parts were in and differences in distortion.

. Thread tempering cause’s constant distortion.

. It is possible to change the print to accommodate for the distortion in a few cases.

. It is recommended to use Miller’s 75 quench oil and slow agitation in the surface combustion furnace.

33

Future work There are several things that could be done as a continuation of this work. One of them is to try to quench with a varying agitation speed during the process. That would allow for a better control over the cooling curve and possibly also decrease the distortion. This could be done by changing the speed manually at the furnaces currently used at Cummins. A furnace where you can change the agitation speed automatically during the process would be even better. At the same time, a higher temperature than the 210 ˚F used here could be tried to see how that affect the distortion. If the furnace at Cummins had been able to handle a temperature of 250 ˚F this would have been possible to include in the present work but unfortunately the furnace could not handle temperatures over the boiling point without risk of exploding.

More tests with different oils would also be interesting as it was a big difference between the two tested in the present work. It may be possible to find even better oils that Miller 75 for this process.

Since gas quenching turned out to be a good choice with respect to the distortion more tests should be performed to investigate if the resulting microstructure is acceptable. Different parameters, i.e. the pressure, could be varied in order to get less troostite in the final microstructure.

For the gas quenching it were a difference between bottom and top blown quench and it would therefore be interesting to investigate how a reversed quench would look for oil quenching. If the caskets is modified in such a way that they can lie with the thicker part down without damaging the threads then this could be done. If the same relationship between bottom and top blown quench exist for oil as for gas this would reduce the distortion.

The thread tempering give a lot of distortions and to resolve this a change to a more powerful source of electricity was suggested in the present work. To test this hypotheses heat treated samples could be sent from Cummins to a company that uses a bigger power source. If the result is better it is worth investing in it.

Something that wasn’t investigated in this project was how the machining tools affected the distortion. A new and old tool should give slightly different distortion since an old tool will give more residual stress than a new one. To see how this affect the distortion several test over the lifetime of the tool should be performed. In that way a specific age of the tool can be specified, before it has to be changed, in order to keep the distortion originating from the tool to a minimum .

34

Acknowledgements I would like to thank my supervisors Andrew Armuth and Danielle Kareus at Cummins for helping me with the all the questions I have had about the project and just working and living in USA. They were a great help for me and without their help it would have been impossible to do this. I would also like to thank my supervisor at KTH, Joakim Odqvist, for his help with the project.

Chuck Thomas and Morgan Thomas at Nitrex were a great help by allowing me to use their quenching furnace, enabling me to compare different oils. Finally there is Anders Eliasson at KTH. Without his offer for this opportunity I would not have done this.

35

Bibliography 1. ASM International. Heat Treater's Guide Practices and Procedures for and . Materials Park, OH : ASM International, 1995.

2. Sensitivity of material properties on distortion and residual stresses during metal quenching processes. Ashok Kumar Nallathambi, Yalcin Kaymak, Eckehard Specht, Albrecht Bertram. pp. 204-210, Magdeburg : Journal of Materials Processing Technology, 2009, Vol. 210.

3. Overview of distortion and residual stress due to quench processing part I: factors affecting quench distortion. Canale L.C.F., Totten G.E. Nos 1-4, pp. 4-52, s.l. : International Journal Materials and Product Technology, 2005, Vol. 24.

4. Herring, Daniel H. The Heat Treat Doctor: Secrets of Effective Hot Oil Quench-ing. Industrial Heating. [Online] Industrial Heating, April 4, 2006. [Cited: Mars 26, 2013.] http://www.industrialheating.com/articles/86820-the-heat-treat-doctor-secrets-of-effective-hot-oil- quench-ing?v=preview.

5. Finite element simulation of quench distortion in a low- steel incorporating transformation kinetics. Seok-Jae Lee, Young-Kook Lee. Seoul : Elsevier Ltd, 2007, Vol. 56.

6. Effect of machining and heating parameters on distortion of AISI 52100 steel bearing rings. Surm, H., Kessler, O., Hoffmann, F. and Mayr, P. Nos 1-4, pp. 270-281, s.l. : Int. J. Materials and Product Technology, 2005, Vol. 24.

7. Study on the Cooling Capacity of Different Quenchant. Lijun Hou, Heming Cheng, Jianyun Li, Ziliang Li, Baodong Shao, Jie Hou. pp. 515-519, s.l. : Procedia Engineering, 2012, Vol. 31.

8. Combinations of coating and heat treating processes: establishing a system for combined processes and examples. O.H. Kessler, F.T. Hoffmann, P. Mayr. pp. 211-216, Bremen : Surface and Coatings Technology, 1998, Vols. 108-109.

9. Herring, Daniel H. Oil Quenching. The Heat Treat Doctor. [Online] 2010. [Cited: 3 25, 2013.] http://www.heat-treat-doctor.com/documents/Vacuum%20Oil%20Quenching%20Tech.pdf.

10. Shimadzu Mectem Inc. VHO Oil/Gas Quenching . [Online] Shimadzu Mectem Inc., 04 01, 2013. [Cited: 04 1, 2013.] http://www.shimadzu-mectem.com/product/furnace/vho.html .

11. Herring, Daniel H. Effects of Contamination on Quench-Oil Cooling Rate. Industrial heating. [Online] January 09, 2002. [Cited: 04 01, 2013.] http://www.industrialheating.com/articles/89944-effects-of- contamination-on-quench-oil-cooling-rate?v=preview.

12. —. Oil Quenching Part One: How to Interpret Cooling Curves. Industrual heating. [Online] The Herring Group Inc., 08 08, 2007. [Cited: 04 01, 2013.] http://www.industrialheating.com/articles/87886- oil-quenching-part-one-how-to-interpret-cooling-curves.

36

13. MacKenzie, D. Scott. Effects of Contamination on Quench-Oil Cooling Rate. industrialheating. [Online] Houghton International Inc., January 9, 2002. [Cited: 3 25, 2013.] http://www.industrialheating.com/articles/89944-effects-of-contamination-on-quench-oil-cooling- rate?v=preview.

14. INFLUENCE OF QUENCHING OILS COMPOSITION ON THE COOLING RATE. Ljiljana Pedišic, Božidar Matijevic, Boris Peric. Pula, Croatia : INTERNATIONAL CONFERENCE ON HEAT TREATMENT AND SURFACE ENGINEERING OF TOOLS AND DIES, 2005.

15. HHV Technology. Gas / Oil quenching furnace . HHV TEchnology. [Online] HHV Technology, 2011. [Cited: 04 01, 2013.] http://hhv.in/categories/vacuum-technology/vacuum--furnaces/gas--oil- quenching%20furnace.

16. Otto, Frederick J. Information about Midwest Thermal - Vac. Columbus, IN, 03 12, 2013.

17. Process technology for distortion compensation by means of gas quenching in flexible jet fields. S. Schuettenberg, F. Frerichs, M. Hunkel and U. Fritsching. Nos 1-5, Bremen : Int. J. Materials and Product Technology, 2005, Vol. 25.

18. Quenching with fluid jets. S. Schuettenberg, F. Krause, M. Hunkel, H.-W. Zoch, U. Fritsching. 5-6, Weinheim : WILEY-VCH Verlag GmbH & Co. KGaA, 2009, Vol. 40. DOI: 10.1002/mawe.200900468.

19. Tejas. m3tubecomponents. m3tubecomponents. [Online] M3 Excellence Limited, November 06, 2011. [Cited: April 02, 2013.] http://www.m3tubecomponents.com/images/AISI%2052100%20SPECIFICATIONS.pdf.

20. Halcomb Steel Co. Colors of heated steels. [Online] Sizes Inc., December 28, 2007. [Cited: May 15, 2013.] http://sizes.com/materls/colors_of_heated_metals.htm.

37

Appendix

Process Capability Sixpack of Bore Distortion Test 1 Xbar Chart Capability Histogram 0.02 LSL Target USL UCL=0.01628

n Specifications a e _ LSL -0.05

M _

e 0.00 X=0.00016 Target 0.00 l

p USL 0.05

m a S LCL=-0.01597 5 0 5 0 5 0 5 4 3 1 0 1 3 4 -0.02 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot

0.08 UCL=0.08066 A D: 5.469, P: < 0.005

e

g n

a _ R R=0.04327

e 0.04

l

p

m a S LCL=0.00589 0.00 1 4 7 10 13 16 19 22 25 -0.05 0.00 0.05

Last 25 Subgroups Capability Plot

0.02 Within Within Overall StDev 0.01520 StDev 0.01451

s 0.00 Cp 1.10 Pp 1.15

e u l Cpk 1.09 Ppk 1.14

a Overall V -0.02 PPM 1004.42 Cpm 1.15 PPM 570.72 Specs 5 10 15 20 25 Sample

Process Capability Sixpack of OD Distortion Test 1 Xbar Chart Capability Histogram 0.06 LSL Target USL UCL=0.05628

n Specifications a

e LSL -0.04

M _ 0.04 _

e Target 0.00 l X=0.03706

p USL 0.04

m a S 0.02 LCL=0.01785

1 4 7 10 13 16 19 22 25 -0.032 -0.016 0.000 0.016 0.032 0.048

R Chart Normal Prob Plot UCL=0.03338 A D: 0.820, P: 0.032

e 0.030

g

n

a

R

e l 0.015 _

p R=0.01022

m

a S 0.000 LCL=0 1 4 7 10 13 16 19 22 25 0.02 0.03 0.04 0.05

Last 25 Subgroups Capability Plot

Within Within Overall StDev 0.009058 StDev 0.007076 0.04

s Cp 1.47 Pp 1.88

e u l Cpk 0.11 O v erall Ppk 0.14 a 0.03 V PPM 372948.44 Cpm 0.35 PPM 339138.32 0.02 Specs 5 10 15 20 25 Sample

38

Process Capability Sixpack of Bore Distortion Test 2 Xbar Chart Capability Histogram UCL=0.01136 LSL Target USL

n Specifications a

e 0.000

_ LSL -0.05

M

e X=-0.00774 Target 0.00 l

p -0.015 USL 0.05

m

a S LCL=-0.02684 5 0 5 0 5 0 5 4 3 1 0 1 3 4 -0.030 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot

0.10 UCL=0.0956 A D: 10.307, P: < 0.005

e

g n

a _ R

0.05 R=0.0513

e

l

p

m a S LCL=0.0070 0.00 1 4 7 10 13 16 19 22 25 -0.05 0.00 0.05

Last 25 Subgroups Capability Plot

Within Within Overall 0.000 StDev 0.01801 StDev 0.01731

s Cp 0.93 Pp 0.96

e u l Cpk 0.78 Ppk 0.81 a -0.025 O v erall V PPM 10143.72 Cpm 0.88 PPM 7728.86 -0.050 Specs 5 10 15 20 25 Sample

Process Capability Sixpack of OD Distortion Test 2 Xbar Chart Capability Histogram 0.06 LSL Target USL UCL=0.05657

n Specifications a e _ LSL -0.04

M 0.04 _

e Target 0.00 l X=0.03459

p USL 0.04

m a

S 0.02 0 5 0 5 0 5 0 LCL=0.01260 3 1 0 1 3 4 6 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 0 0 0 0 0

R Chart Normal Prob Plot

0.04 UCL=0.03820 A D: 1.686, P: < 0.005

e

g

n

a R

0.02 e l _

p R=0.01169

m

a S 0.00 LCL=0 1 4 7 10 13 16 19 22 25 0.02 0.04 0.06

Last 25 Subgroups Capability Plot

Within Within Overall 0.045 StDev 0.01036 StDev 0.007795

s Cp 1.29 Pp 1.71

e u

l 0.035 Cpk 0.17 O v erall Ppk 0.23 a

V PPM 300795.64 Cpm 0.37 0.025 PPM 243790.48 Specs 5 10 15 20 25 Sample

39

Process Capability Sixpack of Bore Distortion Test 3 Xbar Chart Capability Histogram UCL=0.01151 LSL Target USL 0.01

n Specifications a

e _ LSL -0.05 M X=0.00211

e Target 0.00 l 0.00

p USL 0.05

m a S LCL=-0.00730 5 0 5 0 5 0 5 4 3 1 0 1 3 4 -0.01 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 28 31 34 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot UCL=0.04707 A D: 12.287, P: < 0.005

e 0.04

g n

a _ R

R=0.02525 e

l 0.02

p

m a S LCL=0.00344 0.00 1 4 7 10 13 16 19 22 25 28 31 34 -0.02 0.00 0.02

Last 25 Subgroups Capability Plot

Within Within Overall 0.005 StDev 0.008870 StDev 0.008384

s Cp 1.88 Pp 1.99

e u l Cpk 1.80 Ppk 1.90 a -0.010 O v erall V PPM 0.04 Cpm 1.93 PPM 0.01 -0.025 Specs 15 20 25 30 35 Sample

Process Capability Sixpack of OD Distortion Test 3 Xbar Chart Capability Histogram UCL=0.04208 LSL Target USL 0.04

n Specifications a e _ LSL -0.04

M _

e X=0.03058 Target 0.00 l 0.03

p USL 0.04

m

a S 0.02 6 4 2 0 2 4 6 LCL=0.01908 3 2 1 0 1 2 3 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 28 31 34 -0 - 0 -0 -0 0 0 0

R Chart Normal Prob Plot

0.02 UCL=0.01998 A D: 0.781, P: 0.041

e

g

n

a R

0.01 e l _

p R=0.00611

m

a S 0.00 LCL=0 1 4 7 10 13 16 19 22 25 28 31 34 0.02 0.03 0.04 0.05

Last 25 Subgroups Capability Plot

0.04 Within Within Overall StDev 0.005420 StDev 0.004222

s Cp 2.46 Pp 3.16

e u

l 0.03 Cpk 0.58 O v erall Ppk 0.74 a

V PPM 41074.53 Cpm 0.43 PPM 12823.10 0.02 Specs 15 20 25 30 35 Sample

40

Process Capability Sixpac of Bore Distortion Test 4 Xbar Chart Capability Histogram UCL=0.01722 LSL Target USL

n Specifications a 0.01 e _ LSL -0.05

M _

e X=0.00297 Target 0.00 l

p 0.00 USL 0.05

m

a S -0.01 5 0 5 0 5 0 5 LCL=-0.01127 4 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 .0 1 5 9 13 17 21 25 29 33 37 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot 0.08 A D: 25.130, P: < 0.005

UCL=0.07126

e

g

n a

R _ 0.04

e R=0.03823

l

p

m a S LCL=0.00520 0.00 1 5 9 13 17 21 25 29 33 37 -0.05 0.00 0.05

Last 25 Subgroups Capability Plot

Within Within Overall StDev 0.01343 StDev 0.01266

s 0.00

Cp 1.24 Pp 1.32

e u l Cpk 1.17 Ppk 1.24 a Overall

V -0.02 PPM 270.85 Cpm 1.28 PPM 115.46 -0.04 Specs 20 25 30 35 40 Sample

Process Capability Sixpack of OD Distortion Test 4 Xbar Chart Capability Histogram UCL=0.04260 LSL Target USL

n 0.040 Specifications a e _ LSL -0.04

M _

e X=0.03290 Target 0.00 l 0.032

p USL 0.04

m

a S 0.024 3 2 1 0 1 2 3 4 LCL=0.02321 3 2 1 0 1 2 3 4 .0 .0 .0 .0 .0 .0 .0 .0 1 5 9 13 17 21 25 29 33 37 -0 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot A D: 1.638, P: < 0.005

0.016 UCL=0.01684

e

g

n

a

R

e 0.008 l _

p R=0.00515

m

a S 0.000 LCL=0 1 5 9 13 17 21 25 29 33 37 0.02 0.03 0.04

Last 25 Subgroups Capability Plot

Within Within Overall 0.040 StDev 0.004569 StDev 0.003621

s Cp 2.92 Pp 3.68

e u l 0.035 Cpk 0.52 Ppk 0.65 a O v erall

V PPM 60220.40 Cpm 0.40 0.030 PPM 25008.45 Specs 20 25 30 35 40 Sample

41

Process Capability Sixpack of Bore Distortion Test 5 Xbar Chart Capability Histogram UCL=0.00452 LSL Target USL 0.000

n Specifications a e _ LSL -0.05

M _

e X=-0.01391 Target 0.00 l -0.015

p USL 0.05

m

a S -0.030 0 5 0 5 0 5 0 5 LCL=-0.03233 6 4 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot 0.10 A D: 10.138, P: < 0.005

UCL=0.0922

e

g n

a _ R 0.05

e R=0.0495

l

p

m a S LCL=0.0067 0.00 1 4 7 10 13 16 19 22 25 -0.05 0.00 0.05

Last 25 Subgroups Capability Plot

Within Within Overall 0.000 StDev 0.01737 StDev 0.01650

s Cp 0.96 Pp 1.01 e

u -0.025 l Cpk 0.69 Ppk 0.73 a O v erall

V PPM 18982.29 Cpm 0.77 -0.050 PPM 14409.07 Specs 5 10 15 20 25 Sample

Process Capability Sixpack of OD Distortion Test 5 Xbar Chart Capability Histogram LSL Target USL 0.05 UCL=0.05149

n Specifications a e _ LSL -0.04

M _

e X=0.03019 Target 0.00 l 0.03

p USL 0.04

m

a S 0.01 0 5 0 5 0 5 LCL=0.00890 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 0 0 0 0

R Chart Normal Prob Plot 0.04 A D: 0.419, P: 0.316

UCL=0.03700

e

g

n

a R

0.02 e l _

p R=0.01132

m

a S 0.00 LCL=0 1 4 7 10 13 16 19 22 25 0.00 0.02 0.04 0.06

Last 25 Subgroups Capability Plot Within 0.050 Within Overall StDev 0.01004 StDev 0.009168

s Cp 1.33 Pp 1.45

e u l Cpk 0.33 O v erall Ppk 0.36 a 0.025

V PPM 164281.12 Cpm 0.42 PPM 142362.26 0.000 Specs 5 10 15 20 25 Sample

42

Process Capability Sixpack of Bore Distortion Test 6 Xbar Chart Capability Histogram UCL=0.00378 LSL Target USL 0.000

n Specifications a e _ LSL -0.05

M _

e X=-0.01405 Target 0.00 l -0.015

p USL 0.05

m

a S -0.030 0 5 0 5 0 5 0 5 LCL=-0.03188 6 4 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot 0.10 A D: 11.028, P: < 0.005

UCL=0.0892

e

g

n a

R _ 0.05

e R=0.0479

l

p

m a S LCL=0.0065 0.00 1 4 7 10 13 16 19 22 25 -0.05 0.00 0.05

Last 25 Subgroups Capability Plot

0.000 Within Within Overall StDev 0.01681 StDev 0.01592

s Cp 0.99 Pp 1.05 e

u -0.025 l Cpk 0.71 Ppk 0.75 a O v erall

V PPM 16320.65 Cpm 0.78 -0.050 PPM 12017.49 Specs 5 10 15 20 25 Sample

Process Capability Sixpack of OD Distortion Test 6 Xbar Chart Capability Histogram 0.06 LSL Target USL UCL=0.05606

n Specifications a e 0.04 _ LSL -0.04

M _

e Target 0.00 l X=0.03281

p USL 0.04 m

a 0.02 S 2 6 0 6 2 8 LCL=0.00956 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 - 0 -0 0 0 0

R Chart Normal Prob Plot

0.04 UCL=0.04039 A D: 0.675, P: 0.074

e

g

n

a

R

e 0.02 l _

p R=0.01236

m

a S 0.00 LCL=0 1 4 7 10 13 16 19 22 25 0.00 0.02 0.04 0.06

Last 25 Subgroups Capability Plot

0.050 Within Within Overall StDev 0.01096 StDev 0.009316

s Cp 1.22 Pp 1.43

e u

l 0.035 Cpk 0.22 O v erall Ppk 0.26 a

V PPM 255837.59 Cpm 0.39 0.020 PPM 220034.38 Specs 5 10 15 20 25 Sample

43

Process Capability Sixpack of Bore Distortion Test 7 Xbar Chart Capability Histogram UCL=0.00604 LSL Target USL

n 0.000 Specifications a e _ LSL -0.05

M _

e X=-0.01206 Target 0.00 l

p -0.015

USL 0.05

m

a S 0 5 0 5 0 5 0 5 -0.030 LCL=-0.03017 6 4 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot 0.10 A D: 9.932, P: < 0.005

UCL=0.0906

e

g n

a _ R 0.05

e R=0.0486

l

p

m a S LCL=0.0066 0.00 1 4 7 10 13 16 19 22 25 -0.05 0.00 0.05

Last 25 Subgroups Capability Plot

Within Within Overall 0.000 StDev 0.01707 StDev 0.01616

s Cp 0.98 Pp 1.03

e u l -0.025 Cpk 0.74 Ppk 0.78 a O v erall

V PPM 13254.97 Cpm 0.83 -0.050 PPM 9523.81 Specs 5 10 15 20 25 Sample

Process Capability Sixpack of OD Distortion Test 7 Xbar Chart Capability Histogram 0.06 LSL Target USL UCL=0.05622

n Specifications a e LSL -0.04

M _ 0.04 _

e Target 0.00 l X=0.03587

p USL 0.04

m a

S 0.02 0 5 0 5 0 5 0 LCL=0.01552 3 1 0 1 3 4 6 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot 0.04 A D: 0.308, P: 0.550

UCL=0.03536

e

g

n

a R

0.02 e

l _ p

m R=0.01082

a S 0.00 LCL=0 1 4 7 10 13 16 19 22 25 0.02 0.04 0.06

Last 25 Subgroups Capability Plot

0.06 Within Within Overall StDev 0.009593 StDev 0.008020

s Cp 1.39 Pp 1.66

e 0.04 u

l Cpk 0.14 O v erall Ppk 0.17 a

V PPM 333566.39 Cpm 0.36 0.02 PPM 303460.83 Specs 5 10 15 20 25 Sample

44

Process Capability Sixpack of Bore Distortion Test 8 Xbar Chart Capability Histogram UCL=0.00385 LSL Target USL 0.000

n Specifications a e _ LSL -0.05

M _

e X=-0.01344 Target 0.00 l -0.015

p USL 0.05

m

a S -0.030 0 5 0 5 0 5 0 5 LCL=-0.03073 6 4 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 -0 0 0 0 0

R Chart Normal Prob Plot UCL=0.08651 A D: 10.465, P: < 0.005

0.08

e

g n

a _ R

R=0.04641 e

l 0.04

p

m a S LCL=0.00632 0.00 1 4 7 10 13 16 19 22 25 -0.05 0.00 0.05

Last 25 Subgroups Capability Plot

Within Within Overall 0.000 StDev 0.01630 StDev 0.01549

s Cp 1.02 Pp 1.08

e u l -0.025 Cpk 0.75 Ppk 0.79 a O v erall

V PPM 12510.59 Cpm 0.81 -0.050 PPM 9144.50 Specs 5 10 15 20 25 Sample

Process Capability Sixpack of OD Distortion Test 8 Xbar Chart Capability Histogram 0.06 LSL Target USL UCL=0.05433

n Specifications a e LSL -0.04

M 0.04 _ _

e Target 0.00 l X=0.03228

p USL 0.04 m

a 0.02 S 0 5 0 5 0 5 LCL=0.01023 3 1 0 1 3 4 .0 .0 .0 .0 .0 .0 1 4 7 10 13 16 19 22 25 -0 -0 -0 0 0 0

R Chart Normal Prob Plot

0.04 UCL=0.03831 A D: 0.475, P: 0.232

e

g

n

a R

0.02 e l _

p R=0.01172

m

a S 0.00 LCL=0 1 4 7 10 13 16 19 22 25 0.00 0.02 0.04 0.06

Last 25 Subgroups Capability Plot

0.05 Within Within Overall StDev 0.01039 StDev 0.008812

s Cp 1.28 Pp 1.51

e u

l 0.03 Cpk 0.25 O v erall Ppk 0.29 a

V PPM 228757.04 Cpm 0.40 PPM 190419.82 0.01 Specs 5 10 15 20 25 Sample

45