15-5 PH Stainless Steel

15-5 PH Stainless Steel

Specification: AMS 5862, AMS 5659, AMS 5826, ASTM A 564, ASTM SA 564, ASTM A 693,ASME SA 693, ASTM A 705,ASME SA 705

 

15-5PH Precipitation Hardening Stainless Steel Alloy (S15500) is a variant of the older 17-4 PH (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). The 15-5 PH alloy was designed to have greater toughness than 17-4 PH, 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 15-5 PH alloy is carefully controlled to minimize its content of delta ferrite, which is present in the 17-4 PH stainless steel material. Inclusion control is done by consumable electrode remelting using the electro-slag remelting (ESR) process. The 15-5 PH 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 17-4PH alloy, the 15-5 PH stainless steel 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 highest strength, although slightly less than those of semi-austenitic alloys like S17700 (17-7 PH) or S15700 (15-7 PH). The latter precipitation hardening alloys generally require more steps to complete heat treatment. The15-5 PH alloy is generally better-suited for plate applications than are the semi austenitic alloys.