非调质钢36MnVS4汽车发动机连杆胀断缺陷分析

Fracture Splitting Defects Analysis of Automotive Connecting Rod Made of Air-cooled Forging Steel 36MnVS4

通过合金成分测定、显微组织定量分析、室温拉伸力学性能测定,对国内某厂采用国产钢材生产的非调质钢36MnVS4连杆断口不齐、胀不断和断口变形大胀断缺陷进行分析。结果表明:连杆的组织上原奥氏体晶粒过细、铁素体含量超标、存在大量贝氏体,组织均匀性差,连杆的性能上断面收缩率大是产生缺陷的主要原因;明确材料基础特性,采用控锻控冷技术实现对组织性能精确地系统控制是解决胀断缺陷问题的有效途径。

The present work aims at the performance during fracture splitting process of a batch of automotive connecting rod products made of air-cooled forging steel 36MnVS4.The fracture splitting defects,including uneven fracture,unsuccessfully splitting fracture and large deformation after fracture,were analyzed by alloys composition measurement,microstructure quantitative analysis and room temperature mechanical properties determination.The results showed that excessively fine primary austenite grain,overproof ferrite content,enormous bainite,microstructure inhomogeneity,and high section shrinkage are the main causes of the above mentioned defects.The determination of the material＇s basic characteristics and the accurate and systematic control of microstructure and properties by thermo-mechanical control process,would be the effective solution to fracture splitting defects.