Mo和Ni对高强无碳化物贝氏体钢组织转变与力学性能的影响  

Effect of Mo and Ni on Microstructure and Mechanical Properties of Carbide-free Bainite Ultra-high Strength Steels

作　　者：陈雨来[1] 董长征[1] 蔡庆伍[1] 万德成[1] 李亮[1] 齐越[1] 

机构地区：[1]北京科技大学高效轧制国家工程研究中心,北京100083

出　　处：《材料工程》2013年第9期16-21,共6页Journal of Materials Engineering

摘　　要：测定了不含Mo和Ni、含Ni和含Mo三种成分实验钢的CCT曲线,利用扫描电镜、透射电镜观察了连续冷却及轧后空冷条件下三种钢的显微组织变化,并对其力学性能进行了检测分析。结果表明:添加少量Mo和Ni能有效延迟高强无碳化物贝氏体钢CCT曲线中高温铁素体相变,降低Ms点,促进贝氏体相变。Mo和Ni的添加可使实验钢轧后空冷组织由铁素体+粒状贝氏体+M/A混合组织转变为无碳化物贝氏体组织(BF+AR),Ni对贝氏体板条的细化作用比Mo显著,但组织中会出现少量粗大贝氏体;Mo对轧后相变过程中粗大贝氏体的形成有一定抑制作用,可使获得的无碳化物贝氏体组织均匀性更好。Mo和Ni均可有效提高高强无碳化物贝氏体钢的力学性能,其中Ni对抗拉强度的提升作用强于Mo,而Mo则更有利于冲击韧性的提高。含Ni的2#实验钢抗拉强度比不加Ni和Mo的1#实验钢提高252MPa,含Mo的3#实验钢-20℃下冲击吸收功比1#提高11J。Continuous cooling transformation diagrams of three steels with different composition were determined. Microstructure evolution behavior and mechanical properties of three steels that was formed by continuous cooling and rolling in the air were investigated by transmission electron micros- copy and scanning electron microscope. The influences of addition of Mo/Ni on microstructure and mechanical properties of the steels were also analyzed. The results show that adding Mo/Ni can effec- tively delay ferrite transformation and decrease M~ temperature, which equals to promote medium- temperature bainite transformation. The microstructure of the steels evolves from F＋GB＋ M/A to CFB（BF＋AR） after adding Mo and Ni alloy. In general,the thickness of bainitic ferrite in No. 2 hot- rolled plate （with Ni） is thinner than No. 3 steel（with Mo） and coarse bainite can be observed in No. 2 steel which leads to a deterioration in toughness. However, the thickness of bainite ferrite in No. 3 steel（with Mo） varies little and the film shaped carbon-enriched remaining austenite well distributes between BF lathes. The mechanical properties tests of three steels indicate that adding Mo/Ni can re- markably improve both tensile strength and toughness, but Mo and Ni have different effects, adding Ni offers a higher strength while adding Mo is more helpful to improve toughness of high-strength steels.

关 键 词：MO NI 高强钢 显微组织 无碳化物贝氏体 力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]