钢管卧式挤压机用H13挤压针早期失效原因分析

Investigation of Early Stage Failure of H13 Fixed-mandrel of Horizontal Steel Tube Extruding Mill

从裂纹形貌、硬度、残余奥氏体、显微组织、使用等方面对挤压生产不锈钢钢管用H13挤压针开裂甚至断裂的早期失效原因进行了分析。结果表明:在挤压钢管过程中,H13挤压针冷却不良,使挤压针表面发生二次淬火是挤压针开裂的主要原因。提出了通过改造挤压针的冷却系统、热处理工艺等措施,可提高其使用寿命。

Investigation is made into the causes for early stage failure of cracking or even breaking of the H13 fixed-mandrel of the horizontal steel tube extruding mill as occurring during extruding stainless steel tubes, involving such aspects as crack morphology, hardness, residual austenite, microstructure and operation, etc. As a result, it is identified that the major cause for the said failure is that the H13 fixed-mandrel is not well cooled during the tube extrusion operation, and thus the mandrel＇s surface gets secondarily-quenched. Therefore, it is proposed that actions like improving the cooling system of the fixed-mandrel and relevant heat treatment process be taken to prolong the service life of the fixed-mandrel.