PRODUCTION OF STAINLESS STEEL PRODUCTS HAVING HIGH STRENGTH AND EXCELLENT RESISTANCE TO CORROSION, STRESS CORROSION CRACKING AND SULFIDE CRACKING

摘要

PURPOSE:To obtain the titled martensitic stainless steel products which withstand the use in oil well environment by specifying the components and component range of the steel products and specifying heat treatment conditions. CONSTITUTION:The steel products contg. 0.05-0.15% C, =1.00% Si, 0.50-2.00% Mn, =0.025% P, =0.010% S, =0.20% Ni, 0.02-0.10% Nb, =0.20% Cu, 11.0-14.05% Cr, 0.02-0.10% N, =0.10% Al, contg., if necessary, =1.00% Mo and/or =0.10% V at the limit at which the content of the ferrite in the final steel products obtd. by formula I (formula II in the case in which Mo and V are contained) is =20%, and the balance consisting at 900-1,150 deg.C, the steel products are cooled at an average cooling rate of =10 deg.C/min between 800-500 deg.C and are then subjected to a tempering treatment at 600-830 deg.C; thereafter the steel products are cooled at an average cooling rate of =5 deg.C/min between 500-300 deg.C.