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本文研究了两种矿用圆环链专用钢23MnNiCrMo64和20MnVK,经淬火、不同温度回火后的应力腐蚀应力强度因子门槛值K_(ISCC),并进行了组织和断口的电子显微分析。结果表明,随回火温度提高,K_(ISCC)上升;K_(ISCC)与K_(IC)有大致相同的变化趋向。在回火脆区间,K_(ISCC)值出現低谷。造成这一现象的原因是,回火温度的变化造成了钢显微组织的变化,特别是析出相的增加和铁素体的回复,是钢应力腐蚀敏感性降低的主要原因,回火脆区间较高的应力腐蚀敏感性,主要是由于晶界弱化因素与氢的陷阱捕获作用降低了该区的界面结合力。
In this paper, the stress corrosion stress intensity factor K_ (ISCC) of two kinds of special steel 23MnNiCrMo64 and 20MnVK for mine ring are studied after being quenched and tempered at different tempering temperatures. The microstructure and fracture of the steel are analyzed by SEM. The results show that with the increase of tempering temperature, K_ (ISCC) increases; K_ (ISCC) and K_ (IC) have the same trend. In the temper crisp interval, K_ (ISCC) value appears trough. The reason for this phenomenon is that the change of tempering temperature caused the change of the microstructure of steel, especially the increase of precipitation phase and the recovery of ferrite, which is the main reason of decreasing the sensitivity of steel stress corrosion. The higher sensitivity to stress corrosion is mainly due to the fact that the grain boundary weakening factor and hydrogen traps capture reduce the interfacial bonding in this region.