Abstract: The effect of temper rolling (0~3.3%) and natural aging on mechanical properties and bake-hardening performance of 0.7 mm ultra-low carbon bake-hardening steels plate (%:0.0030C,0.008Nb-0.003Ti,0.0030N and 0.0030C,0.012Nb-0.012Ti,0.0042N) annealed at 830 ℃ has been studied. Results show that at beginning with in- creasing temper elongation, due to decrease of Cottrell atmosphere and increase of dislocation density, the yield strength of steels decreases, as the temper elongation of 0.008Nb-0.003Ti steel and 0.012Nb-0.012Ti steel increases respectively up to 0.48% and 0.26%,the yield strength of steels decreases to minimum; then with further increasing temper elongation, due to enhancement of cold work hardening, the yield strength of steel increases. The temper elongation too low and too high lead up to decrease of hake hardening performance. To control temper elongation 0.5%~1.5% is available to get lower yield strength, higher tensile fracture elongation and excellent bake hardening performance of steel. With naturalizing for 3 months, the bake hardening performance and the elongation of steel plate degrade.

摘要： 研究了平整率(0～3.3%)和自然时效对830℃退火0.7 mm超低碳烘烤硬化钢板(%:0.003 0C、0.008Nb-0.003 Ti、0.003 0N和0.0030C、0.012Nb-0.012Ti、0.004 2N)力学性能和烘烤硬化性能的影响。结果表明,最初随平整率增加,由于柯氏气团减少和位错密度增加,屈服强度降低;当0.008Nb-0.003 Ti钢平整率达到0.48%,0.012Nb-0.012Ti钢平整率达到0.26%时,屈服强度降至最低;平整率继续增加由于冷加工硬化增强,钢的屈服强度升高。平整率过低和过高,均会导致烘烤硬化性能下降。平整率控制在0.5%～1.5%时,钢板能获得较低的屈服强度、较高的断后伸长率和最大的烘烤硬化性能。钢板经自然时效3个月,烘烤硬化性能和延伸率下降。

关键词: 平整, , 烘烤硬化, 屈服强度, , 延伸率, 自然时效