局部加热的高强钢热成形变强度工艺

Hot Forming Technology of High Strength Steel with Tailored Properties by Partial Heating

利用局部加热实现了高强钢板变强度热冲压成形,采用电极加热和局部覆盖屏蔽材料两种方法来实施。试验表明,电极加热高温区域为细小的马氏体组织,过渡区域为马氏体、贝氏体和铁素体/珠光体组织,低温区域为铁素体/珠光体组织。通过坯料局部覆盖屏蔽材料的方式得到了尺寸1∶1变强度热冲压成形B柱。红外成像检测仪结果显示,坯料温度由裸露端向覆盖端梯度下降,零件硬度由硬化区向软化区梯度下降,过渡区域的长度约为48 mm。这些表明通过局部加热实现高强钢变强度的同时能得到更小的过渡区域。

The hot stamping forming of the high strength steel with tailored properties was realized by partial heating,which was carried out by electrode heating and local covering shielding material. The test shows that the microstructure of high temperature region of electrode heating is fine martensite, that of transition zone is martensite, bainite and ferrite/pearlite microstructure, and that of low temperature region is ferrite / pearlite microstructure. By means of partial coveting shielding material on billet, the 1：1 hot stamping B-pillars with tailored properties were obtained. The results of inflated imaging detector show that the temperature of the blank decreases from the bare end to the cover end, the hardness of the part decreases from the hardening zone to the softening zone, and the length of the transition region is about 48 mm. These show that a smaller transition region can be obtained at the same time as the high strength steel with tailored properties is realized by local heating.