“TUBULAR RETORT WITH CONTROLLED ATMOSPHERES” AUTHOR: JARRETT A. SMITH M. Code: 200126260 PROJECT ADVISOR: JAIRO ES COBAR M Sc, Dr Ing. UNIVERSITY DE LOS ANDES MECHANICAL ENGINEERING DEPARTMENT BOGOTA, JUNE 2005 IM - 2005 - I - 39 TABLE OF CONTENTS 1 INTRODUCTION..............................................¡ERROR! MARCADOR NO DEFINIDO. 2 OBJECTIVE.....................................................¡ERROR! MARCADOR NO DEFINIDO. 3 REVISION OF BIBLIOGRAPHY........................¡ERROR! MARCADOR NO DEFINIDO. 3.1 OVERVIEW OF POWDER METALLURGY......................¡ERROR! MARCADOR NO DEFINIDO. 3.2 OVERVIEW OF SINTERING......................................¡ERROR! MARCADOR NO DEFINIDO. 3.2.1 Physical Phenomenon - Diffusion..............................¡Error! Marcador no definido. 3.2.2 Schematic of creating a sintering cycle.......................¡Error! Marcador no definido. 3.2.2.1 Delubing stage..............................................................................¡Error! Marcador no definido. 3.2.2.2 P reheating stage / Presintering..................................................¡Error! Marcador no definido. 3.2.2.3 Hot Stage.......................................................................................¡Error! Marcador no definido. 3.2.2.4 Cooling Stage...............................................................................¡Error! Marcador no definido. 3.2.2.5 Slow cooling stage.......................................................................¡Error! Marcador no definido. 3.2.2.6 P urging, a used as needed stage................................................¡Error! Marcador no definido. 3.2.3 Parameters ...........................................................¡Error! Marcador no definido. 3.2.3.1 Temperature – Heat.....................................................................¡Error! Marcador no definido. 3.2.3.2 Gases..............................................................................................¡Error! Marcador no definido. 3.2.3.2.1 Classification of Gases.........................................................¡Error! Marcador no definido. 3.2.3.2.2 Combustion (Explosion) of gases.......................................¡Error! Marcador no definido. 3.2.3.2.3 Ignition (Auto-ignition) of gases........................................¡Error! Marcador no definido. 3.2.3.2.4 Gases for the atmosphere.....................................................¡Error! Marcador no definido. 3.2.4 Sintering Equipment...............................................¡Error! Marcador no definido. 3.2.4.1 Batch Furnaces.............................................................................¡Error! Marcador no definido. 3.2.4.2 Continuous Furnaces...................................................................¡Error! Marcador no definido. 3.2.4.3 Heating Units................................................................................¡Error! Marcador no definido. 3.2.4.4 Gas Pressure and Flow Equipment...........................................¡Error! Marcador no definido. 3.2.4.5 Additional Comparisons.............................................................¡Error! Marcador no definido. 3.2.4.6 Thermocouples.............................................................................¡Error! Marcador no definido. 4 METHODOLOGY.............................................¡ERROR! MARCADOR NO DEFINIDO. 5 RESULTS AND ANALYSIS................................¡ERROR! MARCADOR NO DEFINIDO. 5.1 DETAILS OF CREATING THE RETORT........................¡ERROR! MARCADOR NO DEFINIDO. 5.1.1 Six Channel Data Acquisition...................................¡Error! Marcador no definido. 5.1.1.1 General Architecture of the System.........................................¡Error! Marcador no definido. 5.1.1.2 Block Architecture of Te mperature Sensors..........................¡Error! Marcador no definido. 5.1.1.3 Implementation............................................................................¡Error! Marcador no definido. 5.1.2 Temperature Measurement (Thermocouple) ................¡Error! Marcador no definido. 5.1.3 Adequate Pressure and Flow for Mixing the Processing Gas.......¡Error! Marcador no definido. 5.1.4 Retort construction – Shell.......................................¡Error! Marcador no definido. 5.1.5 Flange of the retort................................................¡Error! Marcador no definido. 5.1.6 Seal of the Retort...................................................¡Error! Marcador no definido. 5.1.7 Work load support..................................................¡Error! Marcador no definido. 5.2 CHARACTERIZATION............................................¡ERROR! MARCADOR NO DEFINIDO. 5.2.1 Characterization Protocol.......................................¡Error! Marcador no definido. 5.2.2 Temperature characterizations .................................¡Error! Marcador no definido. 5.2.3 Fluid Flow Characterization....................................¡Error! Marcador no definido. 6 CONCLUSIONS................................................¡ERROR! MARCADOR NO DEFINIDO. 7 SUGGESTIONS FOR FURTHER DEVELOPMENT..............¡ERROR! MARCADOR NO DEFINIDO. 8 BIBLIOGRAPHY..............................................¡ERROR! MARCADOR NO DEFINIDO. IM - 2005 - I - 39 Listing of Figures Figure 1: The steps in diffusion bonding [Ref. 1].......¡Error! Marcador no definido. Figure 2: Diffusion of atoms to points of contact [Ref. 1].......... ¡Error! Marcador no definido. Figure 3: Generalization of activation energy.............¡Error! Marcador no definido. Figure 4: Schematic of an Arbitrary Sintering Cycle .¡Error! Marcador no definido. Figure 5: Stress-strain curves for 304 stainless steel at vary in hydrogen concentration (given in wt%) [Ref. 8] ...............................................¡Error! Marcador no definido. Figure 6: Furnace Equipment [Ref. 19] ......................¡Error! Marcador no definido. Figure 8: Tubular Recipient Development Model......¡Error! Marcador no definido. Figure 9: Prototype......................................................¡Error! Marcador no definido. Figure 10: Data Acquisition Card ...............................¡Error! Marcador no definido. Figure 11: General Architecture of System ................¡Error! Marcador no definido. Figure 12: Block Architecture of a Temperature Sensor ............ ¡Error! Marcador no definido. Figure 13: Graphical User Interface............................¡Error! Marcador no definido. Figure 14: Format of Results Displayed with Excel ...¡Error! Marcador no definido. Figure 15: Schematic of Configuration for Forming Gas ........... ¡Error! Marcador no definido. Figure 16: A Reducing Sintering Operation Sequence ............... ¡Error! Marcador no definido. Figure 17: Material Candidates for the retort..............¡Error! Marcador no definido. Figure 18: Operating Limits of Various Alloys in a Hydrogen Environment (Nelson Curves) [Ref. 9]...........................................................¡Error! Marcador no definido. Figure 19: Effect of temperature on metal loss from scaling for several carbon and alloy steels in air [Ref. 9] ............................................¡Error! Marcador no definido. Figure 20: General Comparison of the Hot-Strength Amongst Stainless Steels [Ref. 10] ...............................................................................¡Error! Marcador no definido. Figure 21: Time-temperature curves showing effect of carbon content on carbide precipitation, which forms in the areas to the right of the various carbon-content curves.[Ref. 6].............................................................¡Error! Marcador no definido. Figure 22: Family relationships for standard austenitic stainless steels .............¡Error! Marcador no definido. Figure 23: Cyclic Oxidation Resistance [Ref. 10] ......¡Error! Marcador no definido. Figure 24: Effect of Acrylonitrile Content on Permeability of Butadiene- Acrylonitrile Copolymers at 25°C..............................¡Error! Marcador no definido. Figure 25: O-ring compression force [Ref. 2].............¡Error! Marcador no definido. Figure 26: Linear Expansion % vs. Volume Swell %............... ¡Error! Marcador no definido. IM - 2005 - I - 39 Listing of Tables Table 1: Conforming Methods for Green Pieces.¡Error! Marcador no definido. Table 2: Classification of Some Common Gases¡Error! Marcador no definido. Table 3: Limits of Hydrogen by Volume Percentage.......... ¡Error! Marcador no definido. Table 4: Gas Cylinder Specifications ....................¡Error! Marcador no definido. Table 5: Types of Batch Furnaces.........................¡Error! Marcador no definido. Table 6: Types of Continuous Furnaces..............¡Error! Marcador no definido. Table 7: Accuracy of Variable Area Flowmeters.¡Error! Marcador no definido. Table 9: Selected American Standard Pipe.........¡Error! Marcador no definido. Table 10: Maximum service temperatures in dry air, based on scaling resistance [Ref: 6]....................................................¡Error! Marcador no definido. 1 Introduction In this modern world, industries are always searching for a manufacturing process capable of supplying large quantities of exceptionally high quality pieces at reduced costs. One of the answers of the search is powder metallurgy. With it recognized as a useful technology, efforts are continuously exerted in transferring production of parts from the competing manufacturing technologies of machining wrought steel, forging, and casting to powder metallurgy. Most of the transfer