针对某电厂泄水闸孤门油缸在使用过程中发生破裂的问题,对断件进行了现场观察并取样,采用宏观观察、低倍检验、扫描电镜及能谱分析、金相组织分析等方法进行了研究.结果表明,缸体焊缝附近的母材存在网状渗碳体等异常组织导致焊接或焊后热处理时产生热裂纹,同样,因组织异常致使在正常工作压力下,缸体材料无法阻止裂纹扩展,最终导致缸体脆性断裂.%Fracture occurred on oil cylinder of sluice arc gate in some electric power plant, in order to find out the reason, site investigation and sampling from the broken part were carried out, and deep discussion was conducted by using macroscopical observation, macroscopic examination, scanning electron microscope, energy spectrum analysis, metallographic structure analysis and etc. The results showed that some abnormal structure, such as network cementite which exist in base metal nearby oil cylinder weld, caused hot cracks while welding or hot treatment after welding; at the same time, under the normal operation pressure, abnormal structure caused the cylinder body material can not prevent crack from expanding, in the end, the oil cylinder body cracked.
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