17-4 H1150D

17-4 H1150D (UNS S17400, EN 1.4542, Alloy 630), is a martensitic stainless steel containing 15-17.5% chromium (Cr), 3-5% nickel (Ni), and 3-5% copper (Cu). 17-4 is precipitation hardened (PH), a heat treatment process that increases its strength and hardness. 17-4 Condition H1150D is achieved by further double heat treatment of Cond A. This involves aging at 620 °C (1148 °F) for 4 hours, allowing to cool, and then aging at 620 °C (1148 °F) for another 4 hours. The result of this double aging process is a balance of strength, corrosion resistance, and improved mechanical properties over Cond A. As with all martensitic stainless steels, 17-4 H1150D is magnetic.