超高碳钢的回火组织及力学性能

Tempered Microstructure and Mechanical Properties of Ultra-High Carbon Steel

用CM200型透射电子显微镜研究了超高碳钢双相区淬火+中、高温回火后的组织,用Instron型拉伸试验机测定了力学性能。结果表明:650℃的回火组织为等轴状的铁素体与球状的渗碳体,屈服强度0σ.2=1 127MPa,抗拉强度bσ=1 266 MPa,均匀伸长率uδ=8.26%,总伸长率tδ=9.71%,维氏硬度HV为397;450℃回火组织的铁素体保持淬火的形态,回火碳化物为ε碳化物在基体上以断续的片状析出,0σ.2=1 911 MPa,σb=2 028MPa,uδ=tδ=1.88%,HV为595;400℃回火组织中的铁素体保持淬火的形态,回火碳化物在位错处几乎呈网状析出,拉伸无塑性,HV为703。

The microstructure and mechanical properties of quenched in and phaseregion then tempered ultra-high carbon steel studied by using CM200 transmission election microscopy （TEM） and Instron tensile machine. The results show; The microstructure of specimen tempered at 650℃ consists of equiaxed ferrite and spheroidal cementite. The yield strength σ0.2 = 1 127 MPa. The tensile strength σb = 1 266 MPa, the uniform elongation δu =8. 26 %, the total elongation 8, = 9.71%, HV= 397; In the specimen tempered at 450 ℃, the ferrite is of the same form as in quenched sample, the tempered carbide is ε carbide, discontinuously precipitated in platelet, σ0.2 = 1 911 MPa, σb =2 028 MPa, δu =δt = 1.88%, HV=595%,In the specimen tempered at 400 ℃, the ferrite is of the same form again, the tempered carbide is almost precipitated in nets at dislocations no plasticity can be observed, HV=703.