用慢拉伸法研究GC-4超高强度钢的应力腐蚀开裂敏感性

THE INVESTIGATION OF STRESS CORROSION CRACKING CHARACTE- RISTICS OF GC-4 ULTRA-HIGH STRENGTH STEEL USING SLOW STRAIN RATE TECHNIQUE

本文采用慢拉伸试验法研究了GC-4超高强度钢(40CrMnSiMoVA)的应力腐蚀开裂敏感性。结果表明,三种热处理的GC-4钢在典型模拟环境3％NaCl溶液和蒸馏水中都对应力腐蚀开裂敏感。环境介质的存在使该钢的抗拉强度、总应变和断裂能大大降低,而且,阴极极化和阳极极化都使其应力腐蚀开裂敏感性显著提高。分析表明,氢脆和阳极溶解都是导致GC-4钢应力腐蚀开裂的重要原因。

In this paper, the stress corrosion cracking (SCC) characteristics of GC-4(40CrMnSiMoVA) ultrahigh strength steel is investigated using the slow strain rate technique. The results of three differently heat-treated specimens show that GC-4 steel is sensitive to SCC in both 3 % NaCl solution and distilled water. The strength, percentage elongation and fracture energy of the material are greatly reduced in the presence of corrosive media. Moreover both anodic and cathodic polarization can promote SCC behavior further. It is shown that both hydrogen assisted cracking and anodic dissolution are important factors of SCC of GC-4 steel in 3 % NaCl solution.