过时效和平整对冷轧双相钢板强度、塑性及烘烤硬化性的影响

Effect of over Ageing and Temper Rolling on Mechanical Property and Bake Hardenability of Cold Rolled Dual Phase Steel Sheet

以低碳Si Mn系冷轧双相钢为研究对象,探讨了过时效和平整工艺对双相钢板力学性能的影响。发现:过时效温度高于350℃左右时屈服强度和屈强比大幅度提高并出现屈服平台;平整对双相钢力学性能的影响也与过时效温度有关。平整和过时效均对双相钢的BH值有较大影响。过时效温度过高或者双相钢的BH值很低,不施加任何平整和预拉伸的情况下,双相钢的BH值很小。300℃以下温度过时效后进行平整和预拉伸有利于获得较高的BH值。

The effect of over ageing (OA) and temper rolling on the mechanical properties of cold rolled low carbon SiMn dual phase steel sheets has been studied. It is found that the mechanical properties of dual phase steel are greatly affected by OA temperature. The yield strength and YS/TS ratio keeps low at OA temperature of 300 ℃ and below, but increases sharply at 300-350 ℃. The effect of temper rolling on the mechanical properties of steel sheets depends on OA temperature. It has also been found that the bake hardenability (BH) is closely related with the OA temperature and temper rolling. The high OA temperature results in low BH value, and low OA temperature is favorable for getting the adequate BH value only if temper rolling or/and prestraining is applied. Without prestrain or temper rolling, it is unlikely to have annealed dual phase steel sheets with adequate BH.