摘要
以不同卷取温度(分别为670℃和710℃)工业生产的高强度IF钢热轧板为研究材料,进行了不同冷轧压下率(分别为55%、65%、75%和85%)的实验室冷轧试验,结合连续热镀锌线的工艺特点进行了盐浴退火试验,采用金相和力学性能测试方法,研究了热轧卷取温度和冷轧压下率对高强度IF钢力学性能的影响。结果表明,较低温度卷取时,热轧卷晶粒尺寸较细,冷轧退火态晶粒尺寸相对较粗,rm值相对较低。冷轧退火态仍具有较细小的晶粒,但屈服强度明显降低,这与间隙碳原子在退火过程通过NbC粗化被大量清除有关。卷取温度对试验钢冷轧退火态的强度、断后伸长率和nm值几乎没有影响。随着冷轧压下率从55%增加到75%时,退火后铁素体晶粒尺寸变化不明显,当冷轧压下率进一步增加到85%时,铁素体晶粒尺寸有所减小。冷轧压下率对强度和断后伸长率影响较小,对nm值没有影响,而rm值随着冷轧压下率的提高而提高。
Two industrial produced hot-rolled high strength IF steel strips were cold rolled in laboratory cold rolling mill,and then annealed in salt bath according to the process of a continuous hot-dip galvanizing line.Optical microscopy and tensile tests were used to study the effect of coiling temperature（670 ℃ and 710 ℃,respectively） and cold-rolling reduction（55%,65%,75% and 85%,respectively）on their properties.The results showed that,lower coiling temperature refines the grain size of the hot-rolled strip,but the grain size of the cold-rolled and annealed steel is relatively coaser and the rm value is also relatively lower.the ferrite grain size of the cold-rolled and annealed steel remains fine.However,the cold-rolled and annealed steel has much lower yield strength as a result of scavenging of interstitial carbon atoms by means of NbC ripening during annealing.The coiling temperature has little effect on the strength,elongation and nm value of the cold-rolled and annealed steels.An increase of cold rolling reduction from 55% to 75% almost doesn＇t affect the ferrite grain size of the annealed steel.A further increase of cold rolling rduction to 85% only refines the ferrite grain a little.The cold rolling reduction has no obvious effect on strength and elongation and has no effect on nm value.But rm value increases when the cold-rolling reduction increases.
出处
《钢铁钒钛》
CAS
北大核心
2011年第3期40-45,50,共7页
Iron Steel Vanadium Titanium
关键词
高强度IF钢
卷取温度
冷轧压下率
显微组织
力学性能
high strength IF steel
coiling temperature
cold-rolling reduction
microstructure
properties
