烘烤时间对大晶粒低碳钢烘烤硬化性能的影响

Effect of Baking Time on Bake-hardening Behavior of Low-carbon Coarse-grained Steel

测试了大晶粒低碳钢在170℃烘烤不同时间的烘烤硬化(BH)值。通过内耗试验获得了相应烘烤工艺的内耗曲线,研究了烘烤时间对大晶粒低碳钢烘烤硬化性能的影响机制。结果表明,当预变形量为5%,烘烤温度为170℃时,不同烘烤时间的大晶粒低碳钢的BH值均为负值; BH值和SKK峰随着烘烤时间的延长先增加后不变,BH值随着SKK峰的变化而变化,即BH值主要受Cottrell气团强化作用的影响。烘烤1 000 min的钢的BH值达到最大,继续延长烘烤时间,BH值变化不大;当烘烤时间为20 min时,SKK峰值最大;当烘烤时间超过1 000 min时,SKK峰高变化不大。

Bake hardening(BH)value of low-carbon coarse-grained steel after been baking at 170℃for different times was measured,and the internal friction curves corresponding to baking processes were obtained by internal friction experiment.The effect of baking time on bake-hardening behavior of the low-carbon coarse-grained steel was studied.The results showed that when the pre-deformation amount was 5%and the baking temperature was 170℃,the BH values of low-carbon coarse-grained steel baked for different times were negative,the BH value and SKK peak increased first and then remained steady with the extension of baking time,the BH value varied with the change in SKK peak,that is,the BH values was mainly affected by the Cottrell air mass.When the baking time was 1 000 min,the BH value reached the maximum,then less changed as baking time became more long.When the baking time was 20 min,SKK peak reached the maximum,then less changed as the baking time was above 1 000 min.