淬火方式对高强度球扁钢组织与性能的影响  

Influence of quenching way on microstructure and mechanical properties of high strength flat bulb steel at tempering process

作　　者：梁丰瑞[1] 柴锋[1] 苏航[1] 师仲然 LIANG Feng-rui;CHAI Feng;SU Hang;SHI Zhong-ran(Division of Engineering Steel, Central Iron and Steel Research Institute, Beijing 100081, China)

机构地区：[1]钢铁研究总院工程用钢研究所

出　　处：《连铸》2018年第3期67-71,共5页Continuous Casting

摘　　要：利用光学显微镜、EBSD等检测手段研究了高强度球扁钢经感应加热淬火、加热炉加热淬火后的组织与性能差异,并对淬火样品经不同温度（600、630、650、670、680、690℃）回火3 h后的组织与性能进行检测分析。结果表明：两种淬火方式所得组织均为马氏体＋少量贝氏体,感应加热淬火样品组织较加热炉加热淬火组织略细,强度略高。EBSD结果表明,两种淬火方式下淬火马氏体板条块之间均为大角度晶界,板条束之间为小角度晶界。感应加热淬火球头与腹板的平均有效晶粒尺寸（MED_（2°））为2.815μm,加热炉加热淬火球头与腹板的平均有效晶粒尺寸为3.015μm。对不同淬火方式的回火组织来说,回火温度越高,有利于板条界面消失,有利于板条间的界面及原奥氏体晶界处的析出物长大和球化;回火温度越高,强度逐渐降低,塑韧性提高。对于批量生产,采用感应加热淬火热处理,可以获得强韧匹配好,性能均一的球扁钢产品;对于单件生产,实践中可以根据性能需要选择合适的淬火、回火工艺采用加热炉对球扁钢进行调质热处理。Using OM, EBSD and other test techniques, the difference of microstructure and properties of high strength bulb fiat steel after induction-heat quenching and furnace-heat quenching was studied, and the tempering microstructure and properties of the quenched samples were also analyzed after tempering 3 h at different temperatures （600, 630, 650, 670, 680,690 ℃ ）. The results show that microstructure of the two kinds of quenching methods are martensite and a small amount of bainite, and the microstructure of induction heating quenched sample is slightly thinner than that of furnace-heating, and the strength is slightly higher. The results of EBSD show that the martensite blocks in the two quenching modes are both large angle grain boundaries and the laths are small angle grain boundaries. The average effec- tive grain size （MED2o） of bulb head and fiat for the induction heating quenching is 2.815 μm, and for the furnace-heat- ing is 3.015 μm. For tempering microstructures with different quenching methods, the higher tempering temperature is beneficial to the disappearance of lath interface, which is conducive to the growth and spheroidization of precipitates at the interface between lath and original austenite grain boundaries; The higher the tempering temperature, the decrease of the strength and the increase of the ductility and toughness. For batch production, the induction heat treatment is pre- ferred to obtain the flat ball steel products with good strength and toughness and uniform properties; For small batch pro- duction, in practice, the proper quenching and tempering standard can be selected according to the performance require- ments, and the furnace-heating could be used to heat treatment of the ball fiat steel.

关 键 词：感应加热淬火 加热炉淬火 板条束及板条块 有效晶粒尺寸 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG161[金属学及工艺—金属材料]