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采用不同工艺对纳米改性新型高锰钢进行了热处理,并进行了显微组织、力学性能和热疲劳性能的测试与分析。结果表明:780℃热处理后纳米改性新型高锰钢由铁素体和M/A岛组成,晶粒较为粗大;580℃热处理后由铁素体和退化珠光体(DP)组成,晶粒得到细化;与780℃热处理相比,580℃热处理能使纳米改性新型高锰钢的抗拉强度减小47 MPa,屈服强度增大38 MPa,热疲劳裂纹级别从12级增大至14级;800℃×20 min+550℃×40 min等温热处理能使其抗拉强度增大94 MPa,屈服强度增大191MPa,热疲劳裂纹级别从12级减小至8级,力学性能和热疲劳性能得到明显提高。800℃×20 min+550℃×40 min等温热处理后纳米改性钢由铁素体、M/A岛和纳米颗粒状(Nb,Ti)C碳化物组成,其晶粒明显细化。热处理工艺优选为800℃×20 min+550℃×40 min等温热处理。
The new nano-modified high-manganese steel was heat-treated by different techniques, and the microstructure, mechanical properties and thermal fatigue properties were tested and analyzed. The results show that the nano-modified high manganese steel after heat treatment at 780 ℃ consists of ferrite and M / A islands, and the grains are coarse. After heat treatment at 580 ℃, ferrite and degenerate pearlite (DP) Compared with heat treatment at 780 ℃, heat treatment at 580 ℃ can reduce the tensile strength of nano-modified high manganese steel by 47 MPa and yield strength by 38 MPa, and increase the thermal fatigue crack growth grade from 12 to 14 ; 800 ℃ × 20 min + 550 ℃ × 40 min isothermal heat treatment can increase the tensile strength of 94 MPa, yield strength increases 191MPa, thermal fatigue crack level reduced from 12 to 8, the mechanical properties and heat Fatigue performance has been significantly improved. After isothermally heat-treated at 800 ℃ for 20 min and 550 ℃ for 40 min, the nanostructured steel consisted of ferrite, M / A island and nano-sized (Nb, Ti) C carbides with grain refinement. The heat treatment process is preferably 800 ℃ × 20 min + 550 ℃ × 40 min isothermal heat treatment.