汽车覆盖件冲压模具用球墨铸铁的研究

DUCTILE IRON FOR AUTOMOTIVE COVERING PART STAMPING DIE

设计并研究了5种不同成分球墨铸铁的铸态机械性能和表面感应淬火性能。结果显示,全珠光体基体并含有一定量的碳化物形成元素Mo和Cr可使球墨铸铁感应淬火后获得更高的表面硬度。浇注中提早打箱处理可显著提高珠光体球墨铸铁的抗拉强度。最佳试样QT4的抗拉强度为830MPa,延伸率为2.2%,感应淬火后表面平均硬度为60HRC,淬硬层厚度可达4.5mm。

The ductile iron samples with 5 different compositions were designed, and their as-cast mechanical properties and performance after surface induction hardening were studied. The results showed that full pearlite-matrix and a certain amount of carbide forming elements such as Mo and Cr could be the improvement factors to reach a higher surface hardness after induction hardening. Dis- mantling mold during casting at early stage could also enhance the tensile strength of pearlite-matrix ductile iron significantly. The QT4 ductile iron sample was of the best performance, i.e. 830 MPa tensile strength, 2.2% elongation, and the average hardness of surface after induction hardening was up to 60 HRC, the depth of hardened layer was up to 4.5 mm.