Abnormal Failure Analysis of H13 Punches in Steel Squeeze Casting Process

摘要

In steel squeeze casting process,the working condition of a punch was very rigorous.The abnormal failure models of an H13 punch,such as plastic rubbed damnification,could not be avoided easily.Based on the analysis of the flow stress and the friction-shearing stress of an H13 punch in steel squeeze casting process,the following results were obtained:if the flow stress of an H13 punch was smaller than its friction-shearing stress,these abnormal failures could not be avoided;and if there were some protection measures that enable the flow stress to have a greater value than its friction-shearing one,the abnormal failures would not occur.In the production of 45 steel valves and catenary system components,the flow stress of a lateral H13 punch without any protection measure was about 29 MPa and its friction-shearing stress was about 51 MPa,then,the abnormal failures occurred;however,when the protection measures of the punch enabled its working temperature to have a value below 682 deg C ,its flow stress was greater than its friction-shearing stress,and the abnormal failures were avoided.