Cr对高强度集装箱用钢动态CCT曲线和组织的影响  

Effect of Cr on dynamic CCT curves and microstructure of container steel with high strength

作　　者：赵培林[1,2] 孙新军[1] 王振强[1] 张正延[1] 雍岐龙[1] 

机构地区：[1]钢铁研究总院结构材料研究所,北京100081 [2]莱芜钢铁集团技术中心,山东莱芜271104

出　　处：《材料热处理学报》2013年第11期125-131,共7页Transactions of Materials and Heat Treatment

摘　　要：在Gleeblel500D热模拟试验机上，测定不含cr和含cr为0．79％、1．26％三种集装箱用钢的动态CCT曲线，通过光学显微镜和透射电镜观察试验钢不同条件下的显微组织形貌特征，并采用显微硬度法检测其维氏硬度。结果表明，0．1—50℃／s冷速范围内，试验钢均出现明显的珠光体和贝氏体转变区；在添加0．79％，1．26％Cr后，贝氏体转变区明显增大且向低冷速方向扩展。随着冷速的增加，不含cr试验钢由铁素体到贝氏体转变，而含1．26％Cr试验钢由铁素体，贝氏体转变到马氏体转变；同时，随着冷速的增加，硬度逐渐升高；含cr试验钢较不含cr试验钢的硬度升高幅度大。在10～30℃／s时，含Cr0．79％试验钢屈服强度达到700MPa以上；含Crl．26％试验钢屈服强度达到800MPa以上，冷速为50℃／s时，屈服强度达到1000MPa以匕。Hot compression tests of a low carbon container steel and 0.79% , 1.26% Cr alloyed container steels were conducted on a Gleeble 1500D thermal simulator and the CCT curves of the steels were determined based on the experiments. Microstructure of the steels under different processing conditions was investigated by means of optical microscope and transmission electron microscopy. Viekers- hardness was detected by micro-hardness method. The results show that with the cooling rates at O. 1 -50 ℃/s, transformation zones of pearlite and bainite appears in the test steels after 20% hot compression at 900 ℃. For the Cr-alloyed test steels, the transformation zone of bainite enlarges obviously and expands towards the low cooling rate direction. With the cooling rate increased, the phase transformation of the test steel without Cr changes from ferrite,perlite to bainite while that of the test steel with 0.79% Cr and 1.26% Cr is transformed from ferrite, peartite, bainite to martensite. Meanwhile, with increasing cooling rate Vickers-hardness of the steels increases obviously, and the increasing of hardness for the test steel with Cr is more evidently than that of the test steel without Cr. The yield strength of the steels with 0. 79% Cr and 1.26% Cr reaches more than 700 MPa and 800 MPa when the cooling rate in the range of 10 - 30 ℃/s, respectively. The yield strength of the test steel with 1.26% Cr can reach more than 1000 MPa with cooling rate of 50 ℃/s.

关 键 词：集装箱用钢 CR CCT曲线 显微组织 显微硬度 

分 类 号：TG142.4[一般工业技术—材料科学与工程]