15-5 PH Seamless Pipe - Ferrite-Free High Toughness PH Pipe | Sakshi Forge

15-5 PH (UNS S15500 / XM-12 / EN 1.4545) is a delta-ferrite-free martensitic precipitation-hardening stainless steel seamless pipe engineered to overcome the transverse directional toughness limitations of standard 17-4 PH. Its chemistry is tightly controlled to 14.0%-15.5% Chromium, 3.5%-5.5% Nickel, 2.5%-4.5% Copper, and 0.15%-0.45% Niobium. Rebalancing the chromium and nickel ratios completely eliminates delta-ferrite from the microstructure. This ferrite-free structure imparts exceptional short-transverse impact toughness, crack propagation resistance, and uniform multi-directional mechanical properties. Like 17-4 PH, 15-5 PH achieves ultra-high yield strengths (up to 1170 MPa / 170 ksi) via a simple low-temperature aging heat treatment (H900 to H1150). Sakshi Forge manufactures 15-5 PH seamless pipes per AMS 5659 and ASTM A564 standards, processed via ESR (Electro-Slag Remelting) or VAR (Vacuum Arc Remelting) for extreme cleanliness. It is widely specified for critical aerospace structural piping, aircraft hydraulic control lines, nuclear components, and high-pressure defense applications.