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经淬火+回火或正火+回火两种不同热处理的2 1/4Cr-1Mo高压容器钢,在高温高压氢中抗氢腐蚀的能力显著不同。在550°～580℃的温度范围和13.5～31兆帕的高压氢作用下,正火+回火处理的2 1/4Cr-1Mo钢的膨胀速率比淬火+回火处理的大一个数量级以上。经金相、电镜、扫描电镜、透射扫描电镜和能量发射谱分析,发现正火+回火钢的组织发生了显著变化,而淬火+回火钢组织则比较稳定。其原因是正火+回火钢中M_3C碳化物的含铬量较淬火+回火钢中的低。正火+回火钢中的M_2C型碳化物也欠稳定,因而其抗氢腐蚀能力较差。
After quenching + tempering or normalizing + tempering two different heat treatment of 2 1 / 4Cr-1Mo high pressure vessel steel, high temperature and high pressure hydrogen hydrogen corrosion resistance is significantly different. In the temperature range of 550 ~ 580 ℃ and high pressure hydrogen of 13.5 ~ 31 MPa, the expansion rate of normalized and tempered 2 1 / 4Cr-1Mo steels is more than an order of magnitude larger than that of quenched and tempered steel. Microstructure, electron microscopy, scanning electron microscopy, transmission electron microscopy and energy emission spectrum analysis showed that the microstructure of normalized and tempered steel changed significantly, while the microstructure of quenched and tempered steel was stable. The reason is that normalizing + tempered steel M_3C carbide chromium content than quenching + tempering steel in the low. M_2C carbides in normalizing and tempering steels are also less stable and therefore have less resistance to hydrogen corrosion.