In this study failure of deflector rods of a cracking unit in a petrochemical plant was investigated. The rods were exposed to harsh carbonaceous/oxidative working condition at high temperature (≈800 °C). Failure of the rods was reported after 40,000 h of operation. Optical examinations indicated a rough surface with severe localized spallation at some locations on the rods. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that metal dusting in addition to spallation led to surface deterioration. Hardness profilometry showed a remarkable increase in hardness at exposed surface. Furthermore, tensile test results showed significant reduction in elongation of the failed rods. Loss of ductility in severely carburized rods, had caused brittle fracture during service. Overall it was concluded that metal dusting and oxide scale spallation were the main cause of the failure.

在这项研究中，研究了石化厂裂化装置导流杆的失效。棒在高温（≈800°C）下暴露于苛刻的碳/氧化工作条件下。据报道，在操作40,000小时后，杆发生了故障。光学检查表明，粗糙的表面在棒的某些位置有严重的局部剥落。扫描电子显微镜（SEM）和X射线衍射（XRD）分析表明，除散裂外，金属粉尘还会导致表面变质。硬度轮廓测定法显示暴露表面的硬度显着增加。此外，拉伸试验结果表明，失效棒的伸长率显着降低。严重渗碳棒的延展性降低，在使用过程中造成了脆性断裂。