摘要
探讨了回火温度对低碳Mn-Si-Cr钢的空冷无碳化物贝氏体/马氏体复相组织及水淬马氏体组织强韧性的影响。试验表明:经中温回火的空冷无碳化物贝氏体/马氏体复相组织具有较高的强韧性,且中温回火的无碳化物贝氏体/马氏体复相组织的J积分断裂韧度需用J_(1C)来表征。经360℃火后,空冷无碳化物贝氏体/马氏体复相组织的强韧性为σ_(0.2)=1355 MPa,σ_b=1600 MPa,δ_5=13.5％,φ=56.2％,A_K=81 J,相同钢的水淬马氏体组织的强韧性为σ_(0.2)=1350 MPa,σ_b=1617 MPa,δ_5=14.1％,φ=59.5,A_K=67.5 J。其原因在于中温形成的无碳化物贝氏体具有较高的回火抗力,而无碳化物贝氏体中的热稳定性较高的富碳膜状残余奥氏体使钢呈现较高的韧性。
Effect of tempering temperature on the combination of strength and toughness of air cooled carbide free bainite-martensite (CFB/M) microstructure and water quenched martensite (M) microstructure for a low carbon Mn-Si-Cr steel is experimentally investigated. The results show that CFB/M microstructure compared with M microstructure has a better combination of strength and toughness after intermediate temperature tempering. The fracture toughness of the steel with CFB/M microstructure should be characterized by J1c while that of the steel with M could be characterized by K1c after tempering. After tempering at 360 ℃ ,the combination of strength and toughness of the steel with CFB/M microstructure is σ0.2 = 1355 MPa, σ=1600 MPa, δ=13.5 %, φ=56.2 %, Ak=81 J, while that of the same steel with M microstructure is σ0.2=1350 MPa, σb=1617MPa, δ5=14.1%, φ=59.5, AK=67.5 J. The cause might be that CFB has a higher temper resistance than M. And carbon enriched retained austenite film in CFB with a good thermal stability might improve the toughness of the steel after tempering at intermediate temperature.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2003年第8期27-31,共5页
Journal of Mechanical Engineering
基金
国家重点基础研究发展规划基金(G1998061513)
