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HomeMy WebLinkAboutType 17-7 Stainless Steel Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a registered trademark of ATI Properties, Inc. © 2014 ATI. All rights reserved. VERSION 1 (2/17/2014): PAGE 1 of 5 Allegheny Technologies Incorporated 1000 Six PPG Place Pittsburgh, PA 15222-5479 U.S.A. www.ATImetals.com Technical Data Sheet ATI 17-7™ ATI 17-7™ Precipitation Hardening Stainless Steel (UNS S17700) INTRODUCTION ATI 17-7™ Precipitation Hardening Alloy (S17700) is a chromium-nickel-aluminum precipitation hardening stainless steel used for applications requiring high strength and a moderate level of corrosion resistance. The S17700 alloy has been available for many years and has found application in aerospace and many spring type applications requiring high strength. ATI 17-7 precipitation hardening alloy may be formed in a soft austenitic condition and hardened to a high strength level by low temperature heat treatments. The low temperature allows minimum distortion compared to conventional quench and temper hardening processes. In addition to material produced by the standard refining procedures, material which has been vacuum arc or electroslag remelted is available for further increase in resistance to fatigue, for those applications subject to cyclic stresses. SPECIFICATIONS & CERTIFICATES The ATI 17-7 Precipitation Hardening Alloy (S17700) is covered by the following specifications. Specification Product Form AMS 5528 Sheet, Strip and Plate AMS 5529 Sheet and Strip, Cold Rolled AMS 5568 Welded Tubing AMS 5644 Bars and Forgings AMS 5678 Wire AMS 5824 Welding W ire ASTM A 313 Spring W ire ASTM A 564 Bar, Wire, and Shapes ASME SA 564 Bar, W i re and Shapes ASTM A 579 Forgings ASTM A 693 Plate, Sheet and Strip ASME SA 693 Plate, Sheet and Strip ASTM A 705 Forgings ASME SA 705 Forgings Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a registered trademark of ATI Properties, Inc. © 2014 ATI. All rights reserved. VERSION 1 (2/17/2014): PAGE 2 of 5 Allegheny Technologies Incorporated 1000 Six PPG Place Pittsburgh, PA 15222-5479 U.S.A. www.ATImetals.com Technical Data Sheet ATI 17-7™ Typical Analysis Carbon 0.09 max Manganese 1.00 max Phosphorus 0.040 max Sulfur 0.030 max Silicon 1.00 max Chromium 16.00-18.00 Nickel 6.50-7.75 Aluminum 0.75-1.50 Iron Balance PRODUCT FORMS ATI 17-7 precipitation hardening alloy is furnished as plate, sheet and strip from ATI. In all forms, the material is furnished in the annealed condition. In strip form, the material may be provided in a cold rolled condition suitable for direct precipitation hardening heat treatment at 900°F (482°C). PHYSICAL PROPERTIES Condition A Condition RH 950 Condition TH 1050 Density lb/in3 kg/m3 0.282 7810 0.276 7640 0.277 7670 Linear Coefficient of Thermal Expansion Units of 70-200°F 10-6/°F (10-6/°C) Temperature Range: (21-93°C) 8.5 (15.3) 5.7 (10.3) 5.6 (10.1) Magnetic Permeability Weakly Ferromagnetic Strongly Ferromagnetic Strongly Ferromagnetic Strongly Ferromagnetic in Conditions R and T Thermal Conductivity Approximately 9.5 Btu-ft/hr-ft2-°F (16.5 W/m-K) in the hardened conditions in the range 70-300°F (20-150°C) Electrical Resistivity Approximately 80 microhm-cm in annealed or hardened conditions MECHANICAL PROPERTIES Elastic Modulus and Modulus of Rigidity (Typical Values) Condition A Condition RH 950 Condition TH 1050 Modulus of Elasticity Units of 106 psi (GPa) 29 (200) 29 (200) 29 (200) Modulus of Rigidity Units of 106 psi (GPa) 11 (75) 11 (75) 11 (75) Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a registered trademark of ATI Properties, Inc. © 2014 ATI. All rights reserved. VERSION 1 (2/17/2014): PAGE 3 of 5 Allegheny Technologies Incorporated 1000 Six PPG Place Pittsburgh, PA 15222-5479 U.S.A. www.ATImetals.com Technical Data Sheet ATI 17-7™ Room Temperature Properties (Typical Values) (Sheet and Strip) Condition A Condition RH 950 Condition TH 1050 0.2% Yield Strength psi (MPa) 50,000 (345) 200,000 (1380) 175,000 (1205) Ultimate Tensile Strength psi (MPa) 120,000 (825) 225,000 (1550) 195,000 (1345) Elongation (percent) 30 7 8 Hardness Rockwell Hardness Scale 85 B 47 C 42 C Condition CH 900 The room temperature tensile properties of ATI 17-7 precipitation hardening alloy are greatly affected by cold rolling before aging. The properties attainable in CH 900 sheet and strip are summarized in AMS 5529. These properties are listed below: Condition Minimum Yield Strength psi (MPa) Minimum Tensile Strength psi (MPa) Sheet & Strip Cold Rolled to Condition C 175,000 (1205) 200,000 (1380) Sheet & Strip Cold Rolled and Aged to Condition CH 900 230,000 (1585) 240,000 (1655) CORROSION RESISTANCE Tests have shown that the corrosion resistance of ATI 17-7 alloy is comparable to that of Type 304 stainless steel in most media. In general, the corrosion resistance of ATI 17-7 alloy is superior to that of the hardenable 400 series stainless steels. WELDABILITY The ATI 17-7 precipitation hardening alloy is weldable by conventional inert gas methods. The precipitation hardening reaction in the alloy is dependent on the presence of aluminum, a reactive element. For this reason, inert gas methods are used to protect against the loss of aluminum. As-welded ATI 17-7 alloy will be substantially austenitic and will exhibit mechanical properties which are roughly equivalent to annealed (Condition A) material. The ductility of the weld eliminates the need for preheating and postweld annealing procedures required for the conventional and age hardenable martensitic alloys. To produce high strength welds, however, full post-weld heat treatment (solution annealing plus austenitic conditioning, transformation and precipitation hardening) is necessary. HEAT TREATMENT Typically the ATI 17-7 precipitation hardening alloy is furnished is the annealed condition, Condition A. In this condition, the material possesses an austenitic structure. As an austenitic material, the ATI 17-7 precipitation hardening alloy possesses a relatively low strength. This is the condition in which formability is easiest. To develop the high precipitation hardened strength of the alloy by heat treatment, starting from Condition A, heat treatments are done to accomplish two necessary steps. The first is a heat treatment which allows the relatively stable austenite of Condition A to transform to martensite (Austenite Conditioning and Transformation). The second is a precipitation hardening heat treatment to further strengthen the material. The austenite is easier to transform to martensite using a lower temperature heat treatment. For this reason, Condition TH 1050 uses a 1400°F (760°C) heat treatment to produce a martensite transformation around room Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a registered trademark of ATI Properties, Inc. © 2014 ATI. All rights reserved. VERSION 1 (2/17/2014): PAGE 4 of 5 Allegheny Technologies Incorporated 1000 Six PPG Place Pittsburgh, PA 15222-5479 U.S.A. www.ATImetals.com Technical Data Sheet ATI 17-7™ temperature, and this is followed by a precipitation hardening heat treatment at 1050°F (565°C). If Condition RH 950 is desired, the austenite conditioning heat treatment is conducted at 1750° (955°C). In this case, the martensite transformation is not complete until the material is held for some time at -100°F (-73°C). When the transformation is complete, the material is precipitation hardened at 950°F (510°C) to Condition RH 950. Because the precipitation hardening reaction can be driven past peak strength by high temperature or excessive time at the aging temperature, higher temperature or longer time precipitation hardening heat treatments produce lower strength levels. When ATI 17-7 precipitation hardening alloy with an austenitic structure is cold worked by substantial deformation, a transformation to martensitic structure results from the deformation. In this condition, Condition C, the material may be precipitation hardened directly by heat treatment at 900°F (482°C) to condition CH 900. During heat treatment, ATI 17-7 alloy expands approximately 0.004 in/in from Condition A to the RH or TH Conditions. The heat treatments used for the ATI 17-7 precipitation hardening alloy are summarized on Page 5. Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a registered trademark of ATI Properties, Inc. © 2014 ATI. All rights reserved. VERSION 1 (2/17/2014): PAGE 5 of 5 Allegheny Technologies Incorporated 1000 Six PPG Place Pittsburgh, PA 15222-5479 U.S.A. www.ATImetals.com Technical Data Sheet ATI 17-7™