TRON C@ 50
I ~ Stainle~s
.Best corrosion resistance of all stainless steels
.Exceptionally low magnetic permeability
.Strength almost double Type 316
~ Hi9h Performance Alloys
-444 Wilson St . = Tipton, IN 46072 Phone: (765)675-8871 FAX: (765) 675-7051 Product Data Bulletin Product Description 2 NITRONIC 50 %Min %Max COm~ositi~n ,.""""..,..., ,2 Stainless Steel Carbon 0.030 0.050 Speclfl~atlons """" 2 Product Manganese 4.00 5.50 Annealing Temperature 3 Phosphorus 0.040 Metric Practice ...""".""""...3 Description Sulfur 0.015 Silicon 0.20 0.60 Mechanical Properties , 3-8 HPAlloys NITRONIC 50 Chromium 20.50 22.00 Galling/Wear Resistance 9 Stainless Steel provides a Nickel 11.75 13.00 Physical Properties ,.., 9-10 co~bination of corrosion Molybdenum 2.00 2.50 ., resistance and strength not 0.75 Corrosion ResIstance"...1D-15 found in any other com- Copper Nitrogen 0.24 0.30 Fabrication """" """"...16 mercial material available Titanium 0.020 Forging " 16 in its price range. This Aluminum 0.020 .austenitic stainless steel has Anne.allng , ",,16 corrosion resistance greater Boron 0.0008 0.0025 Columbium 0.12 0.20 Welding ", ,."""".,..,,16-17 than that provided by Tantalum 0.10 Machinability,., , 18 Types 316, 316L 317 and Tin 0.030 Castings ...,." , ,.,...,., 19 317L plus approximately Vanadium 0.10 0.30 t stren lgth at Case Histories ..,..,.., 19-BC twiCe tthe yield Tungsten 0.15 room empera ure. n addition, NITRONIC 50 Stainless Steel has very good mechanical proper- ties at both elevated and sub-zero temperatures. And, unlike many austenitic stainless steels, NITRONIC 50 does not become mag- netic when cold worked or cooled to sub-zero tem- peratures, High Strength (HS) NITRONIC 50 Stainless Steel has a yield strength about three times that of Type 316 stainless steel.
Available Forms HPAlloys NITRONIC 50 Stain- less Steel is available in bar, master alloy pigs, ingots and forging quality billets. Forms available from other manu- facturers include castings, extrusions, seamless tubing and plate. NITRONIC50 StainlessSteel is covered by U.S.Patent3,912,5Q3.
The information and data in this Data referring to mechanical prop- Armco. the Armco Trlongle. NITRONIG. product data bulletin are accurate erties and chemical analyses are 17-4PH.I5-5PH.17-7PH.ondPHI3-8Mo ore registered frodemorks of Armco Inc to the best of our knowledge and the result of tests performed on beliet but are intended for general specimens obtaIned from specific Hoste"oy ond Hoynes ore frodemorks of Hoynes Intemotionol. information only. Applications sug- locations of the products in accor- gested for the materials are de- dance with prescribed sampling Inconel ond Monel ore trodemorks of Intemotionol Nickel Go. Inc scribed only to help readers make procedures: any warranty thereof their own evaluations and deci- is limited to the values obtained at sions. and are neither guarantees such locations and by such proce- nor to be construed as express or dures. There is no warranty with implied warranties of suitability for respect to values of the materials these or other applications. at other locations.
2 Other specification The newton (N) has been coverage is pending. It is Metric Practice adopted by the S I as the suggested that HPAlIoysbe The values shown in this metric standard uni.tofforce contacted for information bulletin were established in as'discussed in the A1S1 concerning additional lJ.$.. customary units. The Metric Practice Guide. The metric equivalents of U.S. term for force per unit of area coverage. customary units shown may (stress) is the newton per be approximate. Conversion square metre (N/m2). Since Annealing to the metric system, known this can be a large number, as the International System the prefix mega is used to Temperature of Units (SI), has been indicate 1 ,000,000 units and HPAJIoysNITRONIC 50 accomplished in accordance the term meganewton per Stainless Steel can be with the American Iron and square metre (MN/m2) is supplied annealed at 1950 F Steel Institute Metric Practice used. The unit (N/m2) has to 2050 F (1066 C to Guide,1978. been designated a pascal 1121 C). For most (Pa). The relationship applications, the 1950 F between the U.S. and the SI (1066 C) condition should units for stress is: 1000 be selected, as it provides a pounds/in2 (psi) = 1 kip/in2 higher level of mechanical (ksi) = 6.8948 mega- properties along with newtons/m2 (MN/m2) = excellent corrosion 6.8948 megapascals (MPa). resistance. When as-welded Other units are discussed in material is to be used in the Metric P.ractice Guide. strongly corrosive media, the 2050 F (1121 C) condition should be specified in order to minimize the possibility of intergranular attack.
Table 1 Minimum Properties Acceptable for Material Specification Annealed Bars I:longation Reduction of Area UTS 0.2% VS %in2" % Condition psi (MPa) psi (MPa) (50.8 mm)
Annealed 1950F(1066C)to 35 55 2050F(1121 C)and 100,000 (690) 55.000 (379) water Quenched (up to 144 in' [9290cm2])
Over 144 in2 (9290 cm2) 95.000 (655) 50.000 (345} 30 45 to 324 in' (2091 cm2)
3 Table 2 Typical Room Temperature Properties* 1 II (25.4 mm) Diameter Bar
Table 3 Typical Short- Time Elevated Temperature Tensile Properties*
Test Temperature UTS 0.2% VS I Elongation Reduction of Area Condition F (C) ksi (MPa) ksi (MPa) % in 2" (50.8 mm) %
Annealed 1950F 75 (24) 124 (855) 78 (538) 405 675 (1066C) 200 (93) 112 (772) 66 (455) 405 675 Bars 3/4 t 01-1/4" 400 (204) 102 (703) 58(400) 375 67 (191 to 3 1.8mm! 600 (316) 98 (676) 54 (372) 375 64 Diameter 800 (427) 94 (648) 50 (345) 395 63 1000 (538) 89 (614) 48(331) 365 625 1200 (649) 80 (552) 44 (303) 365 63 1350 (732) 68 (469) 42 (290) 425 71.5 1500 (816) 50 (345) 32 (221 ) 595 85 Annealed 2050 F 75 (24) 117 (8071 60 (414) 45 71 (1121 C) 200 (93) 107 (738) 50 (338) 435 705 Bars1"to1-1/2" 400 (204) 96 (662) 38 (262) 435 695 (254 to 38,1 mm) 600(316) 92(634) 35 (241 ) 425 675 Diameter 800 (427j 89(614) 34(234) 43.5 66 1000(538) 84(579) 32 (221) 41 665 1200(649) 74(510) 31 (214) 38 64 1350(732) I 66(455) 31 (214) 37 615 1500 (816) 52 (359) 30 (207) 41 61 Average of triplicate tests from each of three heats
Table 4
Typical Stress-Rupture Strength* Stress for Failure, ksi (MPal Test Temp.
Condition F (C) 10.000 Hours (estimatedl
Annealed 1950F 72 (496) (1066CI 47 (324) Bars 314" to 1.1/4.. 22 ( 152) (191- 31 Smm) 6 (41.4) Diameter 1.3 19.0)
Annealed 2050 F 1000 (538) (1121C) 1100(593) 65 (448) 54 (372) 43 (296) Bar~ 1" to 1-1/2" 1200(649) 50 (345) 41 (283) 325 (224) (254-381mm) 1350(732) 29 (2001 15 (103) 85 (586) Diameter 1500 (816) 13 (8961 65(448) 35 (241)
.Average of tests from three heats
4 Table 5 Typical Creep Strength* 1" (25.4 mm) Diameter Bar
Table 6 Typical Mechanical Properties* Cold Drawn Wire
Reduction
Cold Reduction UTS 0.2% VS Elongation of Area
% ksi (MPa) ksi (MPa) % in 4 x D %
15 165 ( 1138) 143 (986) 23 56 30 194(1338) 174(1200) 15 49 45 216 (1489) 196 (1351) 11 45 60 234(1613) 216(1489) 9 42 75 246(1696) ,: 234(1613) 8 39
.Average of duplicate tests. Starting size 114" (635 mm) dia rod annealed at 2050 F (1121 C).
Incommon with other NITRONIC alloys, NITRONIC 50Stainless Steel, when cold reduced 60% or more without in-process anneals, will embrittle very rapidly when exposed ettempereturea in the range of 600to 1000 F (426 to 538 C). Therefore. springs made of NITRONIC 50 Stainless Steel should not be given the low-temperature. stress-relief treatment commonly used for austenitic stainless steels.
Table 7 Typical Sub-Zero Mechanical Properties* 1" (25.4 mm) Diameter Bar -Annealed 2050 F (1121 C)
Test Temp UTS 0.2% VS Elongation Reduction
F (CI ksi (MPa) ksi (MPa) % in 2" (50.8 mm) of Area %
-100 (-73) I 146 (1007) 85 (586) 495 65 -320(-196) ! 226(1558) 128(883) 41 51
.Average of duplicate tests
Table 8 Typical Impact Strength 1" (25.4 mm} Diameter Bar -Annealed 2050 F (1121 C}
Test Temp Impact -Charpy V-Notch. ft-Ibs (JI F (C) Simulated HAl.
75 (24) 170 (230) II 170 (230) -100 (-731 115(156) , 115(156)
-320(-196) 50 (68) II 50 (68)
.Heat treated at 1250 F (677 C) for 1 hour to simulate the heat-affected zone of heavy weldments. Average of duplicate tests.
5 Fatigue Strength Table 17 Rotating Beam Fatigue Tests
Fatigue Strength at 10. Reversals of Strel Condition ksi(MPa}
Tested in Seawater*
Annealed 2050 F 1 n dia 42 (290)
( 1121 CI (25.4 mm) Annealed 1950 F (1066CI High-Strength (HS) Bars 1" dia 68 (469) 18 ( 124) (Hot Rolled Unannealed) (25.4 mm)
2-1/2" dia 58(4001 (63.5 mm)
4" dia 44 (303) 15(103) I (102 mm) I
.R R Moore specimens tested at room temperature .McAdam specimens tested .in ambient temperature seawater (11-31 C) at Laaue Corrosion Laboratory. Wrlghtsville Beach. NC Shear Strength Tests from one heat for each size and condition The shear strength of NITRONIG 50 Stainless Steel in double shear has been determined following Boeing Aircraft Go. 02-2860, Procedures for Mechanical Testing of Aircraft Structural Fasteners. The results, determined from atypical heat, are as shown.
Elastic Properties The elastic properties of annealed NITRONIC 50 at room temperature are as shown.
Notch Sensitivity Tensile tests were performed at room temperature using Table 20 notched specimens with a Elastic Properties at Elevated Temperatures* stress-concentration factor of Kt = 1.3. The following Temperature data at right show HPAloys F ICI Poisson's Ratio
NITRONIC 50 Stainless 72(22) 28.9 x 106 (199x1031 0.312 Steel is not notch sensitive. 200(93) 27.8x106 (192x103) 0.307 300(149) 27.0x106 (186x103) 0.303 400 (204) 26.1 x 106 (180 x 103) 0.299 500(260) 25.3 x 106 (174x1031 0.295 600(315) 24.6x1Q6 (170x103) 0.291 700 (371) 24.0 x 106 (165 x 103) 0.288
*Tests performed on sheet samples in the longitudinal direction using strain gages.
Table 21 Notch Sensitivity
Condition U 1:0 -NotcneO. kSI IM pa)
Annealed 2050 F (1121 C) 1145 (790) 155 ( 1069) Annealed 1950 F (1066 C) 1205 1830) High-Strength (HS) Bars 151 (1041) 1965 (1354)
Average of duplicate tests
8 Table 22 Galling and Weight Loss of Couple* Wear mg/1000 cycles
Resistance
The galling re~i,stance of HPAloysNITRONIC 50 Stainless Steel is similar to Type 316 or just slightly better. Metal-to-metal wear tests demonstrate the superiority of NITRONIC 50 over alloy K-500 despite the higher hardness of the latter. Test Conditions Taber Met-Abrader machine. 500" 0 crossed (90") cylInders. dry. 16-lb load. 105 RPM. room tem- Comparative wear data are perature. 120 grit surface finish. 10.000 cycles. degreased. duplicates. weight loss corrected for density differences shown. For applications requiring Table 23 superior galling, wear and Cavitation Resistance of Annealed NITRONIC 50 Stainless Steel cavitation resistance coupled with good corrosion resistance, HPAloysNITRONIC 60 Stainless Steel should be considered.
Table 24 Density at 75 F (24 C) Wire. 7.88 gm/cmJ Typical Magnetic Permeability at Field Strength of
.285 Ibs/inJ Condition 50 Oer. (3978 AIm) 100 Oer (7957 A/m) 200 Oer (15.914 A/m) Electrical Resistivity at 70 F Annealed '004 1004 (21 C) -82 microhm-cm Cold Drawn 27% '004 1003 Cold Drawn 56% '004 1004 Magnetic Permeability Cold Drawn 75% '004 1004 HPAJIoysNITRONIC 50 .Average of duplicate tests Stainless Steel does not become magnetic when severely cold worked. This characteristic makes the alloy useful for applications requiring a combination of excellent corrosion resistance and low magnetic permeability. The magnetic permeability of HP.AJoysNITRONIC 50 Stainless Steel remains very low at cryogenic temperatures, but not as low as HPAJIoys NITRONIC 33 and NITRONIC Reference: Advances in croyogenicEngineering Materials, Vol. 26 (1980), pp. 37-47. 40 Stainless Steels. The magnetic susceptibility data in Table 25 were obtained on also occurs with HPAlIoys mill-annealed sheet samples NITRONIC 33 and NITRONIC using the Curie Force Method. 40 Stainless Steels, is Note that the magnetic dependent on temperature susceptibility of HPAHoys but not on field strength. NITRONIC 50 Stainless Steel Unlike the AISI 300 series exhibits a cusp at stainless steels, most HPAlIoys approximately -400 F ( -240 NITRONIC Alloys show no C). This phenomenon, which supermagnetism.
9 Coefficient of Thermal Expansion Corrosion Table 26 Resistance Coefficient of Thermal Expansion Annealed Material* HPAlloysNITRONIC 50 Stainless Steel provides Coefficient of Thermal Expansion Temperature Range outstanding corrosion F (C) microinches/in/Q F, (!lm/m. K) resistance -superior to 70-200 (21-93) 90 (16.2) Types 316, 316L, 317 and 70-400 (21-204) 92 (16.6) 317L in many media. For 70-600 (21-316) 9.6 (17.3) many applications the 70-800 (21-427) 9.9 (17.8) 1950 F ( 1066 C) annealed 70-1000 (21-538) 10.2 (18.4) condition provides adequate 70-1200 (21-649) 105 (189) corrosion resistance and a 70-1400(21-760) 10.8 (19.4) higher strength level. In very 70-1600(21-871) 11.1 (20.0) corrosive media or where Average of duplicate tests material is to be used in the as-welded condition, the Table 27 2050 F (1121 C) annealed Thermal Contraction condition should be specified. High-Strength (HS) NITRONIC 50 bars are useful for applications such as shafting and bolting, but do not quite exhibit the corrosion resistance of the annealed conditions in all environments. Typical corrosion rates obtained from laboratory tests on NITRONIC 50 Stainless Steel in its several conditions are shown in Table 29 along with comparable data for Types 316, 316L, 317 and 317L stainless steels.
Thermal Conductivity
Table 28
lemperature Thermal Conductivity. F (CI BTU/hr/ft2/in/OF (W/m.K)
70 (21) 300 (149) 108 (15.6) 600(316) 124 (17.91 900(482) 141 (20.3) 1200(649) 160 (23.01 1500 (816) 175 (25.2) .Average of duplicate tests
10 Table 29 Laboratory Corrosion Test Data
Corrosion Rates in Inches per Year IIPY) Unless Otherwise Indicatedl11
NITRONIC 50 Bar NITRONIC 50 Bar I NITRONIC 50 Types 316 & Types 3'7 & 316L I Test Medium Annealed 1950 F Annealed 2050 F High-Strength Annealed Bar I 3'7L (1066 C) (1121C) (HS) Bar(31 Annealed Bar
10% FeCIJ.25 C -plainl21 < .001 g/in2 <.001 g/in2 < .001 g/in2 011 g/in2 10% FeCIJ.25 C_~eviced{21 < 001 g/in2 < .001 g/in2 < 001 g/in2 186 g/in2 - 1% H2SO4' 80 C <.001 <.001 <.001 0.002 < 001 2% H2SO4' 80 C <.001 <.001 <.001 0.011 <.001 5% H2SO4' 80 C <.001 < 001 <.001 0.060 0036 10% H2SO4' 80 C 0.028 010 0.049 20% H2SO4' 80 C 0.133 0.48 0155 1% H2SO4' Boiling 0.027 2% H2SO4' Boiling 0.064 0.12 5% H2SO4' Boiling 194 0131 0.296 026 10% H2SO4' Boiling 0356 073 20% H2SO4' Boiling 1.64 2.20 . 1%HCI.35C <.001 <.001 < 001 0.012 2% HCI. 35 C 0.024 <.001 0.027. 0.021
1% HCI. 80 C <.001 0239 2% HCI. 80 C 0.439 0.452
65% HNO3, Boiling 0010 0.007 0.012
70% HJPO4' Boiling 0.203 0.154 0.202 , .. 33% Acetic Acid. Boiling <.001 < 001 <.001 <.001 20% Formic Acid. Boiling <.001 0.027 40% Formic Acid. Boiling 0.032 0.034 10%HNOJ+ 1%HF.35C 0.007 0064 10% HNOJ + 1% HF. 80 C 0.069 0.442 l'llmmersion tests performed on 5/8" dia. x 5/8" ( 159 x 15.9 mm) long machined cylinders. Results are average of five 48- hour periods. Specimens tested at 35 C and 80 C were intentionally activated for third. fourth. and fifth periods Where both active and passive conditions occurred, only active rates are shown. 12JExposure for 50 hours with rubber bands on some specimens to produce crevices
131Corrosionrates for hot rolled bars. For other mill products, contact Armco.
Table 30 Laboratory Corrosion Test Data* Cast NITRONIC 50
NITRONIC 50 NITRONIC 50 Test Medium As-Cast Cast + Annealed 2050 F ( 1121 C)
10% FeCIJ -Uncreviced < .001 g/in2 50 hrs., Room Temperature 10% FeCIJ -Crevices .029 g/in2 50 hrs., Room Temperature 5% H2SO4, 80 C 95 MPY 81 MPY 5%H2SO4,Boiling -.418MPY 1% HCI, 35 C < 1 MPY I < 1 MPY 70% HJPO4, Boiling -83 MPY .All tests performed on 5/8" ( 15.9 mm) diameter x 5/8" ( 15.9 mm) long machined cylinders Except for the ferric chloride tests, all results are the average of five 48-hour periods Specimens tested at 35 C and at 80 C were intentionally activated for the third, fourth, and fifth periods. Where both active and passive periods occurred, only active rates are shown.
11 Intergranular Attack Table 31 Intergranular Corrosion Resistance of Cast NITRONIC 50 The resistance of HPAlIoys NITRONJC 50 Stainless Steel Huey Test. JPM to intergranular attack is Annealed * % Ferrite excellent even when sensitized 0.0005 0.0006 at 1250 F (675 C) for one 0.0004 I 0.0015---~ hour to simulate the heat- .2050F(1121 C).112-Hour.WaterQuenched affected zone of heavy ..2050 F ( 1121 C) .112.Hour .Water Quenched + 1250 F (677 C) -112-Hour -Air Cooled. weldments. Material annealed Even sensitized cast NITRONIC 50 stainle.s Steel has an acceptable intergranular corrosion rataless than 0.0020 IPM with up to at 1950 F (1066 C) has very 4% farrita presant. good resistance to intergranular attack for most Table 32 applications. However, when Intergranular Attack Resistance of NITRONIC 50 Bar thick sections of HPAlIoys per ASTM A262 NITRONIC 50 Stainless Steel Practice E are used in the as-welded Condition Copper-Copper Sulfate condition in certain strongly corrosive media, the 2050 F Annealed 1950 F ( 1066 C) 0.00101PM Passed 0.0038 IPM Passed (1121 C) condition gives Annealed 1950 F ( 1066 C) optimum corrosion resistance. + 1250F(677C)- This is illustrated by Table 32. 1 hr.-A.C. Annealed 2050 F ( 1121 C) 0.0009 IPM Passed Annealed 2050 F ( 1121 C) 0.00221PM Passed Stress-Corrosion + 1250F(677C)- Cracking Resistance 1 hr.-A.C. High-Strength (Bar Mill) 0.0031 IPM Passed In common with most High-Strength (PRF) stainless steels, under certain 0.00131PM Passed conditions, HP.AJIoysNITRONIC Edge Intermediate 0.0012 IPM Passed 50 Stainless Steel may Center 0.0011 IPM Passed stress-corrosion crack in hot chloride environments. When tested in boiling 42% MgCI2 solution, a very accelerated test, NITRONIC 50 Stainless Steel is between types 304 and 316 stainless steels in resistance to cracking. There is little difference in susceptibility to cracking whether in the annealed, high-strength (HS), or cold- drawn conditions. This is illustrated by the comparative data in Table 33 using the U-bend-type stress direct-Ioaded tensile-type test corrosion test specimens of method (described in detail NITRONIC 50 in the following in ASTM STP 425, September metallurgical conditions have 1967). Note that this is a been exposed to marine severe test, especially at atmosphere on the 80' lot at these temperatures. For Kure Beach. N.C. marine applications, the (1) Mill Annealed 1950 F following better reflects the (1063 C) resistance of NITRONIC 50 (2) Mill Annealed & Stainless Steel: Sensitized 1250 F (675 C) (3) Cold Rolled 44% (160 ksi yield strength) Tests were begun on June 3. 1970. No failure occurred after 15 years exposure.
12: Sulfide Stress and chokes for valve shafts. Cracking stems and pins, provided this cold working is Both laboratory tests and preceded by an anneal. field service experience Table 34 illustrates the show that HPAloysNITRONIC resistance of HPAlloys 50 Stainless Steel has NITRONIC 50 Stainless Steel excellent resistance to sulfide to cracking in laboratory stress cracking in all tests in synthetic sour-well conditions. NITRONIC 50 solution (5% NaCI + 1/2% Stainless Steel in both the acetic acid, saturated with annealed and high-strength H2S). Comparable data are (hot-rolled) conditions has included for HPA8oys17-4 PH been included in the 1988 Stainless Steel, which is revision of NACE Standard considered acceptable by MR-01-75, "Sulfide Stress NACE for use in sour-well Cracking Resistant Material for Oil Field Equipment,' , at service in the two heat- treated conditions shown. hardness levels up to RC35 maximum. The cold-worked condition to RC35 maximum also is acceptable in valves
Table 34 Resistance to Sulfide Stress Cracklng(1)
Time to Failure. hr.. Under Stress. ksi (MPal -~
Hardness 0.2% VS 160 / 140 125 100 76 50 25 Alloy Condition Rockwell ksi (MPa) (1034) (965) (862) (690) (617) (345) (172)
C22 67 (448) >1000 >1000 >1°001
C33 135 (931) 2041 3201>1000 >1000
C35 146 (1007) 3581
C36 144 (993) 170121 , >10001 >10001>1000
C4 1160 (1103) >100°1 >1000
17-4 PH H 1150+ 1150 C32.5 10 (758) est. 9.5 16 225
17-4 PH H 1150-M C29 85 (586) 13.5 29 850
It)Longitudinal tensile specimens tested according to NACE TM 01-77 12)Ductile creep failure. 131For hot rolled bars only.
NITRONIC 50 Stainless Steel spring temper wire coiled into a spring was exposed to the NACE solution at room temperature under the following conditions:
13 Seawater Resistance NITRONIC 50 Alloy 400 (Ni-Cu) Here is how NITRONIC 50 High-Strength (HS) shafting and Alloy 400 (Ni-Cu) looked after 18 months' exposure in quiet seawater off the coast of North Carolina. The test was conducted without zinc anodes to establish the relative corrosion resistance of NITRONIC 50 High-3trength (HS) shafting. Had zinc anodes been us~d or a bronze propeller fitted to these bars, no crevice corrosion should have occurred. The photograph Wood Block Wood Block was taken after barnacles and other forms of marine life were cleared from the test bars. Before exposure, all specimens were polished tc 120 grit finish, degreased and passivated. They were then clamped into pepper- wood racks and exposed fully immersed in seawater. NITRONIC 50 high-strength (HS) shafting showed no crevice attack under the wooden blocks after the 18 months. One bar of NITRONIC 50 high-strength (HS) shafting remained perfect, while the other showed a few areas of very light crevice attack, < .001 " (0.025 mm) deep under marine attachments. Both samples of.Alloy 400 suffered shallow crevice attack .001 "-.003" (0.025-0.076 mm) deep under the area in contact with the wooden rack, and also under numerous attached barnacles. Type 316 stainless steel tested similarily for nine months suffered random pitting and crevice corrosion under the area in contact These two bars are immersed in quiet seawater for nine months. with the wooden rack and Bright shiny bar at right is HP.Ai7Js,NITRONIC 50 stainless steel, and also under marine at left is Type 316 stainless steel showing considerable pitting and attachments, while crevice corrosion. NITRONIC 50 again remained in perfect condition. These specimens are shown in the photograph.
14 Salt Fog -Marine Pitting Resistance Environment No change was apparent in NITRONIC 50 Stainless Steel in any condition after exposure to 5% NaCI fog at 35 C for 500 hours, or after exposure to marine atmospheres on the 800-foot (24.4m) lot at Kure Beach, North Carolina, for 7V2 years. Similar exposure to marine atmospheres produces light staining on These pieces of bar were all exposed to 10% ferric chloride solution Type 316 stainless steel. for 50 hours at room temperature. A rubber band was placed around each to promote crevice corrosion which sometimes occurs Food Handling in areas where the surface is shielded from oxygen. From left to right, they are HP.AJk1,ISN ITRON IC 50 Stainless Steel, Type 316 HPAlloysNITRONIC 50 stainless steel and Type 304 stainless steel. OnlyHP.AJkr,'s Stainless Steel is considered NITRONIC 50 stainless is still bright and shiny. The Type 316 and suitable for food contact use. Type 304 stainless steels are badly pitted and show severe crevice The National Sanitation corrosion in the area where the rubber bands were placed. Foundation includes HPAlloys NITRONIC 50 Stainless Steel in their .'List of Acceptable Materials for Food Contact Surfaces."
Poly thionic Acid Resistance Poly thionic acids are of the general formulaH~xO6. where x is usually 3, 4 or 5. These acids can form readily in petroleum refinery units, particularly desulfurizers. during shutdown. Stressed U-bend specimens of NITRONIC 50 stainless, in both the annealed condition and after sensitizing at 1250F (677 C) for 1 hour, showed no trace Type 304 Type 316 NITRONIC 50 of cracking after exposure to poly thionic acids for 500 Urea Production photograph, Type 304 hours at room temperature. Ammonium carbamate -an stainless steel became intermediate produced severely etched in two weeks during the manufacture of and Type 316 stainless steel urea- is extremely showed some corrosive corrosive to process attack in all exposed areas equipment. Pump parts in after six weeks. HPAlloys the process are subjected to NITRONIC 50 Stainless Steel a combination of severe remained unaffected after six corrosive attack, high weeks' exposure to this temperatures and cyclical aggressive medium. HPAlloysNITRONIC 50 operating pressures ranging up to 3000 psi. Some parts Stainless Steel is presently made of Type 316L stainless being specified for the blocks, steel have shown surface plungers and related parts of attack in just a few months. reciprocating pumps when A manufacturer of special service requires handling valves tested three stainless ammonium carbamate or steels in ammonium other corrosive materials. carbamate. As shown in the
15 Fabrication Table 36 Nominal Composition and Typical Mechanical Properties Although HPAlloysNITRONIC of Several Austenitic All-Weld-Metal Deposits 50 Stainless Steel is considerably stronger than the conventional 300 series stainless steels, the same fabricating equipment and techniques can be used.
NITRONIC 50 Stainless Steel is readily forged like Type 316 stainless steel, except that it requires more power and the temperature is 2150 F to 2250 F (1177 C to 1232 C).
Like other austenitic stainless steels, NITRONIC 50 must be rapidly cooled. In-process Filler Metals anneals to facilitate cold Filler metal, when added to In addition to the improved forming should be done at the joint, should be HPABoys mechanical properties and 2050 F (1066 C). Please NITAONIC 50W (AWS E/EA corrosion resistance, HPAlloys note Page 3. 209), a matching filler metal NITRONIC 50 Stainless Steel composition that provides can be welded successfully comparable strength and by using any of the corrosion resistance to the conventional welding base metal. However, sound processes that are normally weld joints may also be employed with the austenitic obtained using the stainless steels. conventional austenitic HPAlloysNITRONIC 50 stainless steel fillers such as Stainless is readily arc Types 308L and 309. When welded in all forms. As with using these more common most austenitic stainless filler metal compositions, steels, good weld joint allowances should be made properties can be obtained for the strength and without the necessity of corrosion differences. preheat or post-weld Nominal compositions and annealing. Good shielding of representative mechanical the molten weld puddle is properties are shown for the important to prevent any more common electrode absorption of nitrogen from the atmosphere that could filler rods in Table 36. The result in porosity. weld metal alloys are listed generally in the order of Autogenous, high-power (a) increasing alloy content, density joining processes such as electron beam (EB) (b) increasing strength level, and laser welding should be (c) increasing corrosion used with caution due to the resistance and (d) increasing low FN potential of the base cost. These data show that the metal (FN approximately 2). highest strength levels with Field reports also indicate the possibility of severe good tensile ductility and outgassing during EB welding alloy elements that impart in a vacuum atmosphere. good corrosion resistance Under vacuum conditions, are provided by the HP.AJIoys NITAONIC 50W Electrode. In this outgassing is to be expected for liquid weld some specific applications metal containing a high where the high strength nitrogen level.
16 levels or superior corrosion Table 37 resistance in the weld Typical Mechanical Properties deposits are not required, HPAlloys NITRONIC 50 Stainless Plate Weld Joints other filler metals can be -- Weld Weld UTS 0.2% VS Red. in Failure used to advantage because Elong, Process Filler ksi (MPa) ksi (MPal % in2" Area. % Location of reduced costs and/or ready availability. Shielded The matching weld filler Metal Arc NITAONIC SOW 113 (779) 76 (524) 20 36 Weld (NITAONIC 50W, AWS E/EA (SMA) Metal 209) for HPAloysNITAONIC Gas Metal 50 Stainless Steel is similar Arc (GMA) NITRONIC SOW 112(772) 77 (531) 21 30 Weld to many of the regular Spray Metal austenitic stainless steel filler metals in that a small percentage of the magnetic Heavy Section Weld Resistance Welding ferrite phase has been introduced to assure sound Joint Properties Although no direct resistance weld deposits. The small The mechanical properties of welding experience has been obtained with HPAlloys quantity of the second phase welds in 1-1/4" (32.1 mm) usually produces a magnetic thick plate have been NITRONIC SO Stainless Steel, the similarity of the permeability value of determined using two weld alloy to HPAlloysNITRONIC 40 approximately 1.2 in processes that are normally Stainless Steel suggests a shielded metal-arc weld employed in heavy section good response to resistance deposits. This corresponds welding, namely, (a) shielded to a ferrite number (FN) of metal arc (SMA) or stick spot welding and cross-wire welding techniques. The approximately 6. electrode welding and (b) Highly overalloyed Ni base gas metal arc (GMA) or MIG welding schedules outlined fillers are suggested for welding wit!l the spray mode. in the fabricating bulletin, "Welding HPAlloys Stainless applications requiring high Typical test values that can Steels: ' can be used as a resistance to pitting media or be expected from tensile guide to produce sound, very low as-deposited samples cut transverse to the high-strength joints in both magnetic permeability. weld centerline are shown in Table 37. annealed and cold-reduced Heat input is important in sheet. Average shear GTA Weld Joints obtaining the most satisfactory strength data for spot welded joints in HPAlloys Gas tungsten arc weld joints weld joint. Narrow stringer NITRONIC 40 Stainless Steel have been fused successfully beads rather that a wide appear in the Product Data in several flat-rolled thicknesses "weave" technique should of HPAlloysNITRONIC 50 be used for highest weld Bulletin, "HPAlloysNITRONIC 40 Stainless Steel Sheet and Stainless Steel. Mechanical ductility. Good shielding of Strip." HPAloys NITRONIC SO property values similar to the molten puddle is important Stainless Steel is expected to those of the base metal have to eliminate additional nitrogen perform in a similar manner. been obtained in the as- from the atmosphere that welded condition. could cause porosity. Both For more specific suggestions and for NITRONIC The corrosion resistance of stringer beads and adequate GTA welded joints has been shielding are normal factors SOW filler metal sources, evaluated using the standard in good stainless steel contact Baltimore Specialty Steels Corporation. Huey test (ASTM A 262, welding practice. Practice C) for detecting intergranular attack in stainless steels. Laboratory test experience shows that welds made using the NITRONIC 50W Stainless Steel filler metal exhibit the same resistance to intergranular attack as the base metal.
17 Table 38 Machinability* HPAlloysNITRONIC 50 Stainless Steel has machining Characteristics similar to other 100% austenitic stainless steels. It ., " 0 (254 mm)-annealed-RB 95 is suggested that coated Five-hour form tool life using high-speed tools carbides be considered when Data based on duplicate tests machining all NITRONIC alloys, since higher cutting rates may be realized. Table 39 NITRONIC 50 Stainless Steel is more susceptible to cold Recommended Machining Rates for NITRONIC 50 work hardening than types Cutting Rates. SFM 304 and 316 stainless steels. Machining Operation Also, the alloy has higher Automatic Screw Machine 40-65 strength. Machining tests show the alloy to machine Heavy duty Single or Multiple Spindle and Turret Lathe 40-65 at approximately 21% of the High Speed Tools Rates may be increased 15-30% with cutting rate for B1112. This High-Cobalt or Cast Alloys means NITRONIC 50 Stainless Steel can be machined at lI.utomatic Screw Machine (Swiss Type) approximately 1/2 the cutting Cast Alloy or Carbide Tools rate (SFM) used for Type 304 :5ingle Point Turning or 316 stainless steels, based Carbide Tools on using high-speed tool Roughing 90-140 steels. For that reason, as Finishing 120-190 stated above, coated carbides High Cobalt or Cast Alloy Tools are recommended for best Roughing 50-65 results. Finishing 50-75 Because of the high High-Speed Steel Tools strength of NITRONIC 50 Roughing 30-45 Stainless Steel, more rigid Finishing 50-60 tool and work holders than used for Types 304 and 316 Milling (When using end mills, use two-fluted stainless steels should be type and shorten it 25%) used. Care should be taken Reaming not to allow tools to slide Smooth Finish 15-40 over the alloy. Positive cutting Work Sizing 40-60 action should be initiated as High-speed steel reamers Greatly increased rates soon as possible. The alloy obtainable with carbide tooling provides a good surface Threading and Tapping 10-25 finish. Drilling 30-50 High-speed Drills
18 Table 40 Typical Room Temperature and Short.Time Elevated Temperature HPAlloys NITRONIC 50 Properties of Cast NITRONIC 50 Stainless Steel (CG6MMN) Annealed* Stainless Steel may be 0.2% VS Reduction readily cost by all conven- Text Temperature Elongation F (C) ksi (MPa) % in 2" (50.8 mm) % tional techniques. Castings should be annealed at 75 (24) 93(641) 50 (345) 48 46 2050F ( 1121 C) for 1/2-hour 200 (93) 84 (579) 39 (269) 47 57 54 and water quenched in 400(204) 74(510) 30 (207) 50 27 ( 186) 49 48 order to attain a high level 600(316) 67(462) 800 (427) 65 (448) 27 (186) 47 55 of corrosion resistance, Cast 1000 (538) 60 (414) 25 (172) 46 51 NITRONIC 50 Stainless Steel 1200 (649) I 54 (3721 24 (166) 43 55 is listed as Grade CG6MMN in ASTM A 351/351M and Average of three heats. two tests per heat. A 743.
Surface dia. One valve manufac- turer found NITRONIC 50 A manufacturer of valves Stainless Steel met the for gas wells tested needs better than Type NITRONIC 50 Stainless Steel 316 stainless, and adopted against the material previ- ously used. HPAlloys the material as the stan- NITRONIC 50 Stainless Steel dard for this precision Shafts delivered the part. needed extra corrosion Mounted in the bodies resistance without sacrific- of the company's 30-, 36-, and 48 inch valves, the ing strength. Seal rings for some NITRONIC 50 Stainless Steel high-performance indus- rings give the body seat a trial butterfly valves oper- positive seal with excellent ating at 350 psi must have finish and high resistance high hardness plus superior to cavitation and crevice corrosion resistance to corrosion. The material meet the demands of a also provides high resis- variety of chemical me- tance to mechanical damage. NITRONIC 50 shows better resistance than Types 316 and 316L to pitting and crevice corrosion by sour oil and gas fluids, plus much higher strength. It is included in NACE MR-Ol-75 in both the annealed and high-strength bar conditions.
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