1Cr18Ni9Ti不锈钢在含NH_4~+的NaCl水溶液中应力腐蚀开裂研究

研究了退火态 1Cr18Ni9Ti不锈钢在 78± 5℃的纯NaCl和NH4Cl溶液、NH4Cl +NaCl混合溶液中的应力腐蚀性能。结果表明 ,在 2 2 %NaCl溶液中试样经 10 0 0h试验不发生应力腐蚀开裂 ,而浸在 3%NH4Cl+17%NaCl、5 %NH4Cl+10 %NaCl、5 %NH4Cl+17%NaCl、5 %NH4Cl+2 5 %NaCl 4种混合溶液的试样 ,经过小于 10 0 0h的试验就产生应力腐蚀裂纹或断裂 ,即NH+ 4 促进了 1Cr18Ni9Ti钢在NaCl溶液中的应力腐蚀开裂。根据扫描断口形貌和裂纹扩展途径的金相观察 ,还探讨了在混合溶液中的应力腐蚀机制。

Researches on the SCC of 1Cr18Ni9Ti Stainless Steel in NaCl Solution Containing NH4+

The stress corrosion property of 1Cr18Ni9Ti stainless steel in annealed condition in pure NaCl at 78±5℃, NH4Cl, NH 4 Cl+NaCl solutions was studied. The result shows that SCC did not occur when the sample was in 22%NaCl solution for less than 1 000h, and stress corrosion or cracking occurred when the samples in 3%NH 4C+17%NaCl, 5%NH 4Cl+10%NaCl, 5%NH 4Cl+17%NaCl, 5%NH 4Cl+25%NaCl solutions for less 1 000h, so it was considered that NH+ 4 ion accelerated SCC of 1Cr18Ni9Ti in NaCl solution. The stress corrosion mechanism in mixed solutions was studied based on the metallographic observations of scanning fracture shapes and crack extension direction.