快速回火工艺条件下超高强低碳贝氏体钢的组织与性能

doi:10.13251/j.issn.0254-6051.2023.04.011

摘要/Abstract

摘要： 采用盐浴热处理试验,结合扫描电镜、透射电镜及室温拉伸试验,研究了快速加热+短时保温快速回火条件下超高强低碳贝氏体钢的组织和性能变化规律。结果表明,快速回火工艺下,超高强低碳贝氏体钢发生碳过饱和贝氏体和马氏体中的碳化物析出、铁素体和马氏体的重构以及微合金析出物的析出等现象,进而影响材料的强塑性;在700 ℃以下快速回火时,与以板条状贝氏体(LB)组织为主的复相贝氏体钢相比,以粒状贝氏体(GB)组织为主的钢具有更好的回火稳定性;在750~800 ℃两相区快速回火时,铁素体和马氏体相大量重构,最终形成粗大铁素体和马氏体,抗拉强度大幅提升,屈强强度大幅降低,且以LB组织为主的复相贝氏体钢中重构铁素体晶粒更为粗大,导致其屈服强度更低。

关键词: 超高强低碳贝氏体钢, 快速回火, 组织, 性能

Abstract: Change low of microstructure and properties of an ultra-high strength low carbon bainitic steel under the condition of rapid heating+rapid tempering with short holding time was studied by salt bath heat treatment, scanning electron microscope, transmission electron microscope and tensile test at room temperature. The results show that under the rapid tempering process, carbide precipitates from supersaturated bainite and martensite, ferrite and martensite are reconstructed, and microalloy precipitates are precipitated in steel, which affects the strength and plasticity of the material. When the tempering temperature is lower than 700 ℃, the tested steel with mainly granular bainite (GB) structure has better tempering stability than that with lath bainite (LB) structure. As the temperature rises to the intercritical tempering range of 750-800 ℃, the ferrite and austenite are greatly reconstructed, resulting in the formation of coarse ferrite and martensite, and the tensile strength greatly increases, while the yield strength greatly reduces. Moreover, in the multiphase bainite steel with mainly LB structure, the grain size of reconstructed ferrite is much bigger, which results in even lower yield strength.

Key words: ultra-high strength low carbon bainitic steel, rapid tempering, microstructure, properties

中图分类号:

TG161

邹航, 刘曼, 田俊羽, 徐光. 快速回火工艺条件下超高强低碳贝氏体钢的组织与性能[J]. 金属热处理, 2023, 48(4): 67-73.

Zou Hang, Liu Man, Tian Junyu, Xu Guang. Microstructure and properties of ultra-high strength low carbon bainitic steel under rapid tempering process condition[J]. Heat Treatment of Metals, 2023, 48(4): 67-73.

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