固溶处理的冷却对S32750双相不锈钢组织和力学性能的影响

摘要

对尺寸为30 mm×30 mm×300 mm的S32750双相不锈钢试样进行了1 070℃保温1 .5 h、随后分别炉冷、空冷、5 ×105Pa氮气冷却、油冷和水冷的固溶处理.检测了试样的显微组织和力学性能.结果表明:在真空炉中炉冷固溶处理的S32750钢中出现了脆性相,影响钢的冲击性能;当以大于空冷的速度冷却后,钢为两相组织,并且随着冷却速度的进一步增大,钢的冲击韧度也缓慢增加,但抗拉强度和屈服强度随冷却速度增大的变化不明显.%S32750 dual-phase stainless steel specimens,measuring 30 mm by 30 mm by 300 mm long,were solution treated by heating at 1 070 ℃ for 1 .5 h followed by cooling respectively in furnace,air,nitrogen at a pressure of 5 ×105Pa,oil,and water.The microstructures and mechanical properties of the steel were inspected. The results indicated that the S32750 steel solution treated and cooled in a vacuum furnace exhibited brittle phase which will exert an influence on impact toughness of the steel,and that after solution treating and cooling at a rate of more than air cooling the steel showed a structure consisting of two phases,and as the cooling rate further increased so too did slowly the impact toughness of the steel.The tensile and yield strengths of the steel,however, responded little to increase in the cooling rate of solution treating.