乙烯裂解炉管HP40合金的蠕变性能

Creep Performance of HP40 Alloy for Ethylene Cracking Tube

在900,℃不同应力条件下,对HP40合金高温下的蠕变性能进行研究,观察试验前后显微组织的转变,并得到其蠕变本构方程.同时借助SEM+EDX对组织转变及相成分变化进行深入分析.HP40合金在高温下,随着应力的增加蠕变速率增大.其原始组织骨架状的共晶碳化物(r+M7C3+少量M23C6),经过长时蠕变试验后,逐渐变成条状和块状的M23C6,且有一定量的二次碳化物析出.HP40合金中骨架状共晶碳化物的消失会造成蠕变强度的下降.同时由于蠕变孔洞的出现,导致蠕变性能的下降,加速其蠕变变形的过程.

The changes of microstructure were studied and the creep constitutive equations were obtained through the investigation on the creep performance of HP40 alloy at 900 ℃ on different stress levels. SEM and EDX were used to analyze the changes of microstructures and phase chemical compositions. The results show that, along with the increase in the stress level, the creep rate of HP40 alloy increases correspondingly. After long-term creep test, the original skeleton-like eutectic carbide（r＋M7C3＋a little M23C6） turns into strip and block carbide （M23C6） gradually. Meanwhile, a certain amount of secondary carbide precipitation is also observed. The changes of skeleton-like eutectic carbide cause the decline of creep strength. Moreover, the creep cavity results in the decline of creep performance and accelerates the creep deformation process.