S460G1钢特厚板在调质过程中的组织演变与强韧化机制  

Microstructures Evolution and Strengthing-Toughening Mechanism of S460G1 Steel Heavy Plate During Quenching and Tempering

作　　者：宋欣 李伟 邴纯 于涛 毕建伟 SONG Xin;LI Wei;BING Chun;YU Tao;BI Jianwei(Minmetals Yingkou Medium Plate Co.,Ltd.,Yingkou 115005,China)

机构地区：[1]五矿营口中板有限责任公司,营口115005

出　　处：《机械工程材料》2022年第2期20-30,共11页Materials For Mechanical Engineering

摘　　要：通过严格控制轧制参数对S460G1钢进行热轧,得到厚度150 mm的特厚板,然后进行870~960℃淬火和550~660℃回火处理,研究了钢板的组织演变和强钢化机制。结果表明:热轧钢板由表面向心部的组织依次为针状铁素体→粒状贝氏体→铁素体+珠光体;淬火后,表面组织主要为板条马氏体,1/4板厚处以粒状贝氏体为主,1/2板厚处为铁素体和珠光体;其中900,930℃淬火后1/4板厚处原奥氏体晶粒细小均匀,晶粒尺寸分布集中,范围分别为4.12~31.88,5.02~32.69μm;热轧钢板经930℃淬火与600~630℃回火后,其表面组织为回火索氏体,1/4板厚处及1/2板厚处的组织与淬火态类似,但板条铁素体等轴化及铁素体粗化趋势增加,此时钢板的综合力学性能优良,屈强比不高于0.85;马氏体/奥氏体(M/A)岛的分解、析出物的大量析出、位错消失及板条铁素体等轴化等是其具备良好强韧性的主要原因。150 mm thick S460 G1 steel heavy plate was obtained by hot rolling after strictly controlling rolling process,and then quenched at 870—960℃and tempered at 550—660℃.The microstructure evolution and strengthing-toughening mechanism of the steel plate were researched.The results show that from the surface to the center of hot rolled steel plate,the microstructure was acicular ferrite→granular bainite→ferrite and pearlite.After quenching,the microstructure on the plate surface was lath martensite,one quarter thickness of the plate was mainly granular bainite and the center of the plate were ferrite and pearlite.After quenching at 900℃and 930℃,the original austenite grains at the one quarter thickness of the plate were fine and uniform,and the grain size distribution was concentrated with ranging of 4.12—31.88μm and 5.02—32.69μm,respectively.After quenching at 930℃and tempering at 600—630℃,the microstructure on the plate surface was tempered sorbite,and the microstructures of one quarter thickness and center of plate were similar to those at quenching state,but the trend of equiaxed lath ferrite and coarsened ferrite was strengthened;at this time the steel plate had excellent comprehensive mechanical properties with the yield ratio of not higher than 0.85.Martensite/austenite(M/A)island decomposing,a large amount of precipitate,dislocation eliminating and equiaxial ferrite deforming were the main reasons for the excellent strength and toughness of the hot rolled steel.

关 键 词：S460G1钢特厚板 淬火 回火 组织演变 M/A岛 

分 类 号：TG156.6[金属学及工艺—热处理]