HOT WORKED HIGH-CHROMIUM ALLOY STEEL HAVING EXCELLENT HIGH-TEMPERATURE CORROSION RESISTANCE AND HIGH-TEMPERATURE STRENGTH

摘要

PURPOSE:To make improvement in the hot workability of this high-Cr steel of a specific compsn. added with Ca, Mg, Ti, Zr, etc., while maintaining the respective characteristics intrinsic thereto by controlling O, Si, Mn, Al, etc., harmful in hot working. CONSTITUTION:The high-Cr alloy steel is the steel which contains, by weight %, 0.01 to 0.2 C, =0.5 Si, =0.3 Mn, 22 to 38 Cr, 30Ni+Co=65, 0.1 to 3.0 Mo+W, 0.03 to 1.0 Ti+.b, 0.01 to 0.3 AP, =0.01 S, =0.01 Ca+Mg, 0.002 to 0.2 Zr+Hf+Y, =0.05 N, =0.015 O, consists of the balance Fe, and has -0.02 to +0.02 workability parameter Ze expressed by equation. The Si and Mn are not necessary with this steel but are intruded from scrap. The Si is limited from the view point of weldability and phase stability and the Mn of oxidation resistance. The Al is necessary as a degassing agent but hinders toughness if the ratio thereof is excessively high. The O is limited as the removal of oxides is indispensable for assurance of the respective characteristics intrinsic to the steel.