某油田终端处理厂轻烃区脱乙烷塔塔体钢板存在开裂现象,为了查找钢板的开裂原因,采用理化检验、有限元等方法对其进行分析。结果表明:塔体钢板材料化学成分中的铬元素含量低于标准值,其耐蚀性降低;冷弯处理使钢板组织重新发生马氏体转变,材料的硬度增加,材料表层受到弯曲拉应力,内部的低温介质增加了材料开裂的风险;塔体外表面存在多种加载应力,以及由硫化物、氯离子造成的腐蚀缺陷,其使塔体钢板发生应力腐蚀开裂。

There was a cracking phenomenon in the deethanizer body steel plate of light hydrocarbon area in a terminal treatment plant of an oilfield. In order to find out the cracking reason of the plate, it was analyzed by physical and chemical test, finite element method and other methods. The results show that the chromium content in the chemical composition of the tower plate material was lower than the standard value, and its corrosion resistance was reduced. The cold bending treatment made the microstructure of the plate undergo martensite transformation again, and the hardness of the material increased. The surface layer of the material was subjected to bending tensile stress, and the internal low temperature medium increased the risk of material cracking. There were various loading stresses on the external surface of the tower and corrosion defects caused by sulfide and chloride ions, which caused stress corrosion cracking of the tower plate.