Alloy-625-Spec-Sheet

Alloy 625 (UNS N06625) is an austenitic nickel base superalloy possessing excellent resistance to oxidation and corrosion over a broad range of corrosive conditions, including jet engine environments and in many other aerospace and chemical process applications. The alloy has outstanding strength and toughness at temperatures ranging from cryogenic temperature to 2000°F (1093°C). Alloy 625 also has exceptional fatigue resistance. Alloy 625 derives its strength from the solid solution strengthening effects of molybdenum and columbium on the nickel-chromium matrix. These elements also contribute to the alloy’s outstanding corrosion resistance. Although the alloy was developed for high temperature strength, its highly alloyed composition provides a high level of general corrosion resistance to a wide range of oxidizing and nonoxidizing environments. The levels of chromium and molybdenum provide excellent resistance to chloride ion pitting and the high level of nickel provides resistance to chloride stress corrosion cracking. The material possesses a high degree of formability and shows better weldability than many highly alloyed nickel-base alloys. The alloy is resistant to intergranular corrosion even in the welded condition. Alloy 625 can be produced by vacuum induction melting or AOD refining. Consumable electrode remelting procedures may be used to further refine the material. Applications • Seawater applications • Aerospace components • Chemical processing equipment • Nuclear water reaction components Standards AMS .................5599 ASTM ...............B 443 ASME ...............SB 443 Nickel-Base Superalloy Specification Sheet: Alloy 625 (UNS N06625) Alloy 625 03/31 ONE SANDMEYER LANE • PH I LADELPH IA , PA 19116 -3598 800-523-3663 • FAX 215-677-1430 • www.SandmeyerSteel.com S A N D M E Y E R S T E E L C O M PA N Y Family Owned and Managed - Making Stainless Steel and Nickel Alloy Plate Products Since 1952 Corrosion and Oxidation Resistance The high level of chromium and molybdenum in Alloy 625 provides a high level of pitting and crevice corrosion resistance to chloride contaminated media, such as seawater, neutral salts, and brines. The alloy is resistant to a variety of corrosive media from highly oxidizing to moderately reducing. Tests in geothermal brines indicate Alloy 625 is highly resistant to hot geothermal fluids comparable to Titanium Grade 2. Tests in simulated flue gas desulfurization environments show Alloy 625 highly resistant to the environment in comparison to alloys such as Alloy 316 and comparable to Alloy 276. The following data are illustrative. Typical corrosion rates are in mils/year (mm/a). Crevice Test in 10 Alloy 316 Alloy 625Percent Ferric Chloride Onset Temperature °F (°C) <32 (<0) 104-113 (40-45) for Attack in ASTM Procedure G-48 Alloy 45% Formic 10% Oxalic 88% Formic 99% Acetic Alloy 625 5.0 (0.13) 6.0 (0.15) 9.0 (0.23) 0.4 (0.01) Alloy 316 11 (0.28) 40 (1.02) 9.0 (0.23) 2.0 (0.05) Dilute Reducing Acids— Boiling Solutions* Alloy 1% 5% 10% 1% Sulfuric Sulfuric Sulfuric Hydrochloric Alloy 625 2.2 (0.06) 8.9 (0.23) 25.3 (0.64) 36.3 (0.92) Alloy 316 25.8 (0.65) 107 (2.72) 344 (8.73) 200 (5) * Sulfuric acid test samples activated before tests and hydrochloric acid test samples tested without activation. Boiling Organic Acid Solutions Typical Data in Chloride Solutions Panel Exposures in Seawater Panel Location Alloy 316 Alloy 625Onset Temperature Flowing Seawater Crevice Attack No Attack 1 Month 18 Months Tidal Zone Crevice Attack No Attack 1 Month 18 Months Partial Mud Burial Crevice Attack No Attack 1 Month 18 Months Miscellaneous Environments Environment Alloy 625 Type 316 20% Phosphoric Acid .36 (<0.01) 6.96 (0.18) 10% Sulfamic Acid 4.80 (0.12) 63.6 (1.61) 10% Sodium Bisulfate 3.96 (0.10) 41.6 (1.06) Chemical Analysis Typical Analysis (Weight %) Columbium C Mn P S Si Cr Ni Mo + Ta Ti Al Fe 0.05 0.030 0.010 0.003 0.25 22.0 Balance 9.0 3.5 0.3 0.3 4.0 Welding Alloy 625 can be readily welded by conventional processes used for austenitic stainless steel, including fusion and resistance methods. The material should be in the mill annealed condition and thoroughly descaled and cleaned before welding. Preheating is not required and post-weld treatment is not needed to maintain or restore corrosion resistance. Heat Treatment Alloy 625 is furnished with one heat treatment for optimum properties up to 1200°F (649°C) and another for optimum properties above 1200°F (649°C). The standard anneal at a minimum of 1600°F (871°C) is used for service temperatures up to 1200°F (649°C). When optimum high temperature creep and rupture properties are required, as for service above 1200°F (649°C), a solution anneal at 2000°F (1093°C) minimum is used. In the solution annealed condition, a subsequent stabilization anneal at 1800°F (982°C) minimum is sometimes specified to further increase resistance to sensitization. Physical Properties Density 0.305 Ib/in3 8.44 g/cm3 Specific Gravity 8.44 Melting Range 2350°-2460°F 1280°-1350°C Magnetic Permeability 75°F, 200 oersted 1.0006 Specific Heat 0.098 Btu/lb.-°F 410 Joules/kg-°K Effect of Cold Reduction on Properties of Plate Annealed at 2150°F (1177°C) 0 88Rb 49,500 341 115,500 796 67.0 60.4 5 94Rb 77,500 534 121,000 834 58.0 58.1 10 25 102,500 707 130,000 896 47.5 54.6 15 32 112,500 776 137,000 945 39.0 51.9 20 34 125,000 862 143,000 986 31.5 50.0 30 36 152,000 1048 165,000 1137 17.0 49.3 40 39 167,000 1151 179,500 1238 12.5 41.9 50 40 177,000 1220 189,500 1307 8.5 38.0 60 44 180,500 1245 205,000 1413 6.5 32.7 70 45 201,000 1386 219,000 1510 5.0 25.4 Cold Reduction % Hardness Rockwell C Yield Strength (0.2% Offset) psi (MPa) Tensile Strength psi (MPa) Elongation % Reduction of Area % Oxidation Resistance Alloy 625 has excellent oxidation and scaling resistance at temperatures up to 2000°F (1093°C). It is superior to many other high temperature alloys under cyclic heating and cooling conditions. The following graph compares the weight loss of several stainless steel alloys to Alloy 625 under cyclic oxidation at 1800°F (982°C). Formability Alloy 625 is capable of being formed like the standard austenitic stainless steels. The material is considerably stronger than conventional austenitic stainless steels and consequently requires higher loads to cause the material to deform. During cold working, the material work hardens more rapidly than austenitic stainless steels. The combination of high initial strength and work hardening rate may necessitate the need for intermediate anneals if the cold deformation is extensive. Mechanical Properties Typical Short Time Tensile Properties as a Function of Temperature Typical room temperature tensile properties of material annealed at 1920°F (1065°C) follow. The typical room temperature tensile properties of material solution annealed at 2150°F (1177°C) follow. Yield Strength (0.2% Offset) Ultimate Tensile Strength Elongation (% in 2”) 63,000 psi (430 MPa) 136,000 psi (940 MPa) 51.5 The short time elevated temperature tensile properties of Alloy 625 annealed at 1950°F (1066°C) are shown in the following graph. Chloride Stress Corrosion Cracking Resistance Test Alloy 625 Alloy 316 Alloy 20 42% No Cracks Cracks Cracks Magnesium Chloride 1000 Hours <24 Hours <100 Hours 26% No Cracks Cracks No Cracks Sodium Chloride 1000 Hours 600 Cracks 1000 Cracks Yield Strength (0.2% Offset) Ultimate Tensile Strength Elongation (% in 2”) 49,500 psi (340 MPa) 115,500 psi (800 MPa) 67 Impact Resistance Alloy 625 maintains high impact resistance at low temperatures as shown below. Impact properties may be expected to decrease with extended service in the 1200º to 1600ºF (649º to 871ºC) range. 85 30 Longitudinal 49 66 85 30 Transverse 49 66 -110 - 79 Longitudinal 44 60 -110 - 79 Transverse 41.5 56 -320 -196 Longitudinal 35 47 -320 -196 Transverse 35 47 (a) Charpy Keyhole Specimens (Mean Value of 3 Tests) Test Temperature ºF ºC Orientation Impact Energy (a) Ft-lbs Joules Electrical Resistivity Electrical Resistivity microhm–cm Temperature ºF (ºC) 70 21 128.9 100 38 129.6 200 93 131.9 400 204 133.9 600 316 134.9 800 427 135.9 1000 538 137.9 1200 649 137.9 1400 760 136.9 1600 871 135.9 1800 982 134.9 2000 1093 133.9 Thermal Properties Linear Coefficient of Thermal Expansion (a) (Units of 10-6 ) / ºF / ºC Thermal Conductivity (b) (c) Btu-ft/ft2 h-°F W/m-°K -250 -157 — — 4.2 7.3 -200 -129 — — 4.3 7.4 -100 -73 — — 4.8 8.3 0 -18 — — 5.3 9.2 70 21 — — 5.7 9.9 100 38 — — 5.8 10.0 200 93 7.1 12.8 6.3 10.7 400 204 7.3 13.1 7.3 12.6 600 316 7.4 13.3 8.2 14.2 800 427 7.6 13.7 9.1 15.7 1000 538 7.8 14.0 10.1 17.5 1200 649 8.2 14.8 11.0 19.0 1400 760 8.5 15.3 12.0 20.8 1600 871 8.8 15.8 13.2 22.8 1700 927 9.0 16.2 — — 1800 982 — — 14.6 25.3 Temperature ºF ºC Modulus Data Poisson’s Ratio (a) (µ) 70 21 11.4 79 29.8 205 0.308 200 93 11.2 77 29.2 200 0.310 400 204 10.8 75 28.4 195 0.312 600 316 10.5 72 27.5 190 0.313 800 427 10.1 70 26.6 185 0.312 1000 538 9.7 67 25.6 175 0.321 1200 649 9.2 63 24.4 170 0.328 1400 760 8.7 60 23.1 160 0.329 1600 871 8.2 57 — — — (a) Poisson’s ratio (m) computed from the relation: µ = E-2G 2G Temperature ºF ºC Modulus of Rigidity (G) Units of 106 psi Units GPa Elastic Modulus (E) Units 106 of psi Units GPa (a) Average coefficient from 70°F (21°C) to temperature shown. (b) Measurements made at Battelle Memorial Institute. (c) Material annealed 2100°F (1149°C). Typical Alloy 625 Impact Properties S A N D M E Y E R STEEL COMPANY