摘要
某型液氨槽罐车在运输过程中安全阀突然起跳导致氨气泄露,经后期拆卸发现安全阀弹簧多处断裂。为了保证液氨槽罐车的安全运输,利用直读光谱仪、超景深三维显微镜、扫描电镜、金相显微镜、洛氏硬度计等仪器对失效弹簧进行分析。结果表明:弹簧存在非金属夹杂物,同时弹簧在淬火过程中马氏体的转变是不完全的,经过回火后组织内依旧存在碳化物和铁素体,从而使材质硬度降低。经过扫描电镜分析发现断口特征呈冰糖状,属于沿晶脆性断裂,同时断口上存在许多球状颗粒的氧化物和碳化物,也进一步加大了弹簧的的脆性。因此,非金属夹杂物以及回火后残存的碳化物和氧化物是导致弹簧断裂的主要原因。
During the transportation of a certain type of liquid ammonia tank truck,the safety valve suddenly jumped,causing ammonia leakage.After later disassembly,it is found that the safety valve spring has been broken in multiple places.In order to ensure the safe transportation of liquid ammonia tank trucks,instruments such as direct reading spectrometer,ultra depth of field three-dimensional mi-croscope,scanning electron microscope,metallographic microscope,and Rockwell hardness tester have been used to analyze the failed springs.The results show that there are non-metallic inclusions in the spring,and the transformation of martensite is incomplete during the quenching process of the spring.After tempering,there are still carbides and ferrites in the structure,which reduces the hardness of the material.After scanning electron microscopy analysis,it is found that the fracture characteristics are rock sugar like,belonging to intergranular brittle fracture.At the same time,there are many spherical parti-cles of oxides and carbides on the fracture surface,which further increases the brittleness of the spring.Therefore,non-metallic inclusions,as well as residual carbides and oxides after tempering,are the main causes of spring fracture.
作者
杨志钦
YANG Zhiqin(Guangxi Special Equipment Inspection and Research Institute,Nanning 530219,Guangxi China)
出处
《中国铸造装备与技术》
CAS
2023年第3期83-88,共6页
China Foundry Machinery & Technology
关键词
50CrVA
弹簧钢
非金属夹杂
沿晶脆性断裂
失效分析
50CrVA
Spring steel
Non-metallic inclusions
Intergranular brittle fracture
Failure analysis
