Inconel 600.pdf

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MMPDS-01 31 January 2003 6.2 IRON-CHROMIUM-NICKEL-BASE ALLOYS 6.2.0 GENERAL COMMENTS — The alloys in this group, in terms of cost and in maximum service temperature, generally fall between the austenitic stainless steels and the nickel- and cobalt-base alloys. They are used in airframes, principally, in the temperature range 1000 to 1200EF, in those applications in which the stainless steels are inadequate and service requirements do not justify the use of the more costly nickel or cobalt alloys. 6.2.0.1 Metallurgical Considerations Composition — The complex-base alloys comprising this group range from those in which iron is considered the base element to those which border on the nickel-base alloys. All of them contain sufficient alloying elements to place them in the “Superalloy” category, yet contain enough iron to reduce their cost considerably. Chromium, in amounts ranging from 10 to 20 percent or higher, primarily increases oxidation resistance and contributes to strengthening of these alloys. Nickel and cobalt strengthen and toughen these materials. Molybdenum, tungsten, and columbium contribute to hardness and strength, particularly at elevated temperatures. Titanium and aluminum are added to provide age-hardening. Heat Treatment — The complex-base alloys are heat treated with conventional equipment and fixtures such as would be used for austenitic stainless steels. Since these alloys are susceptible to carburization during heat treatment, it is good practice to remove all grease, oil, cutting, lubricant, etc., from the surface before heating. A low-sulfur and neutral or slightly oxidizing furnace atmosphere is recommended for heating. 6.2.0.2 Manufacturing Considerations — The iron-chromium-nickel-base alloys closely resemble the austenitic stainless steels insofar as forging, cold forming, machining, welding, and brazing are concerned. Their higher strength may require the use of heavier forging or forming equipment, and machining is somewhat more difficult than for the stainless steels. Pertinent comments are included under the individual alloys. 6.2.1 A-286 6.2.1.0 Comments and Properties — A-286 is a precipitation-hardening iron-base alloy designed for parts requiring high strength up to 1300EF and oxidation resistance up to 1500EF. It is used in jet engines and gas turbines for parts such as turbine buckets, bolts, and discs, and sheet metal assemblies. A-286 is available in the usual mill forms. A-286 is somewhat harder to hot or cold work than the austenitic stainless steels. Its forging range is 2150 to 1800EF; when finishing below 1800EF, light reductions (under 15 percent) must be avoided to prevent grain coarsening during subsequent heat treatment. A-286 is readily machined in the partially or fully aged condition but is soft and “gummy” in the solution-treated condition. A-286 should be welded in the solution-treated condition. Fusion welding is difficult for large section sizes and moderately difficult for small cross sections and sheet. Cracking may be encountered in the welding of heavy sections or parts under high restraint. A dimensional contraction of 0.0008 inch per inch is experienced during aging. Oxidation resistance of A-286 is equivalent to that of Type 310 stainless steel up to 1800EF. Some material specifications for A-286 alloy are presented in Table 6.2.1.0(a). Room-temperature mechanical and physical properties are shown in Table 6.2.1.0(b). The effect of temperature on physical properties is shown in Figure 6.2.1.0. 6-4
MMPDS-01 31 January 2003 6.2.1.1 Solution-Treated and Aged Condition — Elevated-temperature data are presented in Figures 6.2.1.1.1, 6.2.1.1.3, and 6.2.1.1.4(a) through (c). Stress rupture properties are specified at 1200EF; the appropriate specifications should be consulted for detailed requirements. Figures 6.2.1.1.8(a) through (e) are fatigue S/N curves for several elevated temperatures. Table 6.2.1.0(a). Material Specifications for A-286 Alloy Specification Form Condition AMS 5525 AMS 5731 AMS 5732 AMS 5734 AMS 5737 Sheet, strip, and plate Bar, forging, tubing, and ring Bar, forging, tubing, and ring Bar, forging, and tubing Bar, forging, and tubing Solution treated (1800EF) Solution treated (1800EF) Solution treated (1800EF) and aged Solution treated (1650EF) Solution treated (1650EF) and aged Figure 6.2.1.0. Effect of temperature on the physical properties of A-286. 6-5
Page 1 and 2: MMPDS-01 31 January 2003 CHAPTER 6
Page 3: MMPDS-01 31 January 2003 6.1.1 MATE
Page 7 and 8: MMPDS-01 31 January 2003 Figure 6.2
Page 15 and 16: MMPDS-01 31 January 2003 6.2.2 N-15
Page 19 and 20: MMPDS-01 31 January 2003 6.3 NICKEL
Page 21 and 22: MMPDS-01 31 January 2003 6.3.1 HAST
Page 25 and 26: MMPDS-01 31 January 2003 60 .5 -hr
Page 27 and 28: MMPDS-01 31 January 2003 6.3.2 INCO
Page 29 and 30: MMPDS-01 31 January 2003 Table 6.3.
Page 33: MMPDS-01 31 January 2003 Next page

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