摘要
利用热膨胀仪研究了DP600双相钢、Q&P钢和22MnB5热冲压成形钢的奥氏体临界转变温度和CCT曲线,分析了合金元素对高强度汽车板相变规律的影响。结果表明,随着加热速率的增加,DP600双相钢、22MnB5钢的Ac_1和Ac_3温度增加。相同加热速率条件下,高强汽车板改变成分对Ac_1影响小,但DP600钢添加Cr后,Ac_3降低约20℃;Q&P钢降低1.0%Si、增加0.47%Al时,Ac_3增加50℃;22MnB5钢改变Si、Mn含量时,Ac_3变化约为10℃。DP600钢添加Cr元素后,奥氏体化曲线呈直线增加,相同温度时的奥氏体转变量明显增加。22MnB5钢中奥氏体化曲线呈直线增加,添加Cr元素后奥氏体化曲线右移,Si元素减少后,奥氏体转变量<40%阶段,奥氏体转变速率增加。Q&P钢奥氏体转变曲线呈直线增加,温度接近Ac_3时增速减缓,加入Al元素后奥氏体转变速率降低。C元素推迟了铁素体、珠光体、贝氏体、马氏体转变;Cr元素推迟了珠光体、贝氏体转变,降低了马氏体临界冷却转变速率,提高了高强汽车钢板的淬透性。
The critical transformation temperatures and CCT curves of DP600 dual- phase steel,QP steel and 22 MnB5 steel were analyzed by thermal dilatometer,and the effect of alloying elements on the phase transformation behavior of high strength auto steel sheets was investigated. The results show that with the increase of heating rate,the critical point Ac_1 and Ac_3 of DP600 steel and 22 MnB5 steel increase. Under the same heating rate,the variation of element content of these auto sheets have little effect on critical point Ac_1. However,after adding Cr element,the Ac_3 of DP600 steel decreases by 20 ℃,and with decreasing 1. 0% Si and increasing 0. 47% Al content of QP steel,the Ac_3 point increases by 50 ℃,and after altering Si and Mn content of 22 MnB5 steel,the Ac_3 alters for 10 ℃. After adding Cr element,austenite-temperature curve of DP600 steel increases straightly,and the amount of austenite increases obviously at the same temperature. The austenite-temperature curve of 22 MnB5 steel increases straightly,and its CCT curve moves to right after adding Cr,and the gradient of austenite transformation-temperature curve increases in amount of austenite transformation less than 40% after the decreasing of Si. The austenite-temperature curve of QP steel increases straightly and the austenite increasing rate slows down when the temperature is closed to the Ac_3 temperature,and the austenitizing rate decreases when Al element is added. The carbon element delays the transformation of ferrite,pearlite,banite and martensite. The Cr element delays the transformation of pearlite and banite,reduces the critical cooling rate of martensite transformation,and improves hardenability of the high strength auto steel sheets.
出处
《金属热处理》
CAS
CSCD
北大核心
2016年第2期28-31,共4页
Heat Treatment of Metals
关键词
高强度汽车钢板
合金元素
奥氏体化
临界点
CCT曲线
high strength auto steel sheet
alloy element
austenitizing
critical point
CCT curve
作者简介
作者简介：吝章国（1971-），男，教授级高级工程师，硕士，主要研究方向为热轧及冷轧钢铁产品及工艺开发，已发表论文20余篇，E-mail：linzhangguo@hebgtjt．com。
通讯作者：熊自柳，高级工程师，博士，联系电话：0311-86510973，E-mail：xiongziliu@hbisco．com
