ATI 15-5™ Precipitation Hardening Stainless Steel (UNS S15500) INTRODUCTION ATI 15-5™ precipitation hardening stainless steel (S15500) is a variant of the older ATI 17-4™ (S17400) chromium-nickel-copper precipitation hardening stainless steel. Both alloys exhibit high strength and moderate corrosion resistance. High strength is maintained to approximately 600°F (316°C). This alloy is designated Grade or Type XM-12 in several specifications. The ATI 15-5™ alloy was designed to have greater toughness than S17400, especially in the through-thickness (short transverse) direction. This improved toughness is achieved by reduced delta ferrite content and control of inclusion size and shape. The composition and processing of ATI 15-5™ alloy is carefully controlled to minimize its content of delta ferrite, which is present in the S17400 material. Inclusion control is done by consumable electrode remelting using the electro-slag remelting (ESR) process. The S15500 alloy is martensitic in structure in the annealed condition and is further strengthened by a relatively low temperature heat treatment, which precipitates a copper containing phase in the alloy. Like the S17400 alloy, the S15500 alloy requires only a simple heat treatment; a one-step process conducted at a temperature in the range 900°F (482°C) to 1150°F (621°C) depending on the combination of strength and toughness desired. A wide range of properties can be produced by this one-step heat treatment. Heat treatment in the 900°F (482°C) range produces the highest strength, although it is slightly less than those of semi-austenitic alloys like S17700 or S15700. The latter precipitation hardening stainless steels generally require more steps to complete heat treatment. The ATI 15-5™ alloy is generally better suited for plate applications than are the semiaustenitic alloys. SPECIFICATIONS & CERTIFICATES ATI 15-5™ precipitation hardening stainless steel (S15500) is covered by the following wrought product specifications. 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. © 2012 ATI. All rights reserved. Allegheny Technologies Incorporated 1000 Six PPG Place Pittsburgh, PA 15222-5479 U.S.A. www.ATImetals.com

ATI 15-5™ Technical Data Sheet PRODUCT FORMS ATI 15-5™ precipitation hardening stainless steel is furnished as plate, sheet and strip and long products. In all forms, the material typically is furnished in the annealed condition. FORMABILITY The tensile data for the ATI 15-5™ precipitation hardening stainless steel indicate that the alloy does not possess the high tensile elongation characteristic of the austenitic stainless steels. The material is capable of being mildly formed but is not capable of being severely formed. Forming is more easily accomplished in the overaged condition (such as...

The oxidation resistance of the ATI 15-5™ alloy is superior to that of 12 percent chromium alloys like Type 410, but slightly inferior to that of Type 430. Precipitation hardening can produce surface oxidation. ATI 15-5™ precipitation hardening stainless steel is readily welded using conventional inert gas methods used for stainless grades. Preheating is not usually required. Postweld heat treating is needed to produce the various precipitation hardened heat treatment properties. If matching filler material is used, properties comparable to those of the parent metal can be produced in the weld...

MECHANICAL PROPERTIES Room temperature tensile properties can vary substantially with heat treatment in the 900°F (482°C) to 1150°F (621°C) range. Values shown below are typical room temperature properties that could be expected for various precipitation hardening heat treatments as well as the 1900°F (1038°C) solution heat treatment. HEAT TREATMENT ATI 15-5™ precipitation hardening stainless steel flat-roll product is produced in the annealed condition. This is also called the solution heat treated condition, or Condition A. Annealing is conducted by heat treating at approximately 1900°F (1040°C)...

SUMMARY OF HEAT TREATING AT115-5™ ALLOYMinimum Properties Specified in Aerospace Material Specification (AMS) 5862 Heat Treat to Produce Martensitic Structure 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...

ATI 15-5™ Technical Data Sheet CUTTING Water jet or saw cutting are the safest methods for cutting. Wet abrasive cutting is typically acceptable, but may produce small cracks due to local overheating. Plasma torch cutting may create cracking in the as-annealed condition, especially if the material is greater than approximately 1 inch (25.4 mm) thick. These cracks may propagate far into the base material. This cracking associated with torch cutting is more likely if bending or machining is performed in the as-annealed condition. As noted elsewhere, in the as-annealed condition only mild forming...