合金元素与退火工艺对冷轧双相钢组织和性能的影响

Effects of alloy elements and annealing process on microstructure and properties of cold rolled dual-phase steel

利用ULVAC-CCT-AY-II连续退火模拟器,探讨了合金元素C、微量Nb与退火温度对双相钢力学性能和组织的影响规律。结果显示,C与Nb对相变温度影响较小,但减少了760℃低温退火时的马氏体含量;微量Nb的加入,组织明显细化;在780℃以下退火时,易出现回复组织;在800℃以上退火时,C含量较高钢的组织中容易生成珠光体;C与Nb的加入,能提高钢的屈服强度与抗拉强度;微量Nb在提高钢强度的同时,伸长率也较未添加Nb的试验钢大;在820℃退火时,Nb微合金化双相钢的综合性能较好。

The influence of carbon,trace niobium and annealing temperature on mechanical properties and microstructure of dual-phase steel were studied by ULVAC-CCT-AY-Ⅱ continuous annealing simulator.The results show that carbon and niobium have little influence on phasetransition temperature,but can reduce the martensite content at 760 ℃ annealing.The microstructure is obviously refined by trace niobium addition,and recovery structure is more likely to be formed when annealing temperature is under 780 ℃.Pearlite is easily formed in the steel with higher carbon content when annealing temperature is above 800 ℃.Furthermore the yield strength and tensile strength are increased by the addition of carbon and niobium.The strength is improved with niobium dual phase steel,and the elongation is also higher than the steel without niobium addition.When annealing temperature is at 820 ℃,the niobium micro-alloyed dual-phase steel can achieve a good comprehensive mechanical properties.