中文摘要：

采用几种不同的热处理工艺对超高碳钢进行球化处理,并对不同热处理状态下的试样进行了组织观察和力学性能测试分析,探讨了热处理对超高碳钢组织和性能的影响.结果表明,随着碳化物球化率的提高,钢的塑性得到明显改善.经840℃×20rmin淬火＋650℃×3h高温回火处理样品因能获得圆整度高的球状碳化物,而拥有σs=576MPa、σb=835MPa的高强度和δ5=18.4%的良好塑性.经1200℃×4h高温正火＋800℃×2h球化退火处理的超高碳钢由于获得的球状碳化物颗粒细小且分布均匀,基体在变形时受到的阻碍作用较弱,故强度较高（σs=622MPa,σb=927MPa）,但塑性稍有下降（δ5=16.0%）.经720℃×3.5h退火处理和840℃×20min空冷＋720℃×2.5h退火处理的超高碳钢尽管含有一定量的片状碳化物,也能获得高的强度（σs＞590MPa,σb＞870MPa）和较好的塑性（δ5＞11%）.

英文摘要：

Several spheroidizing processes were carried out on the ultrahigh carbon steel, and the microstructures and mechanical properties of the samples under different heat treatment were observed and tested. The effect of heat treatment on microstructure and mechanical properties of the ultrahigh carbon steel was discussed. The results show that the toughness of the steel is improved remarkably with the increase of the spheroidizing ratio of carbides. The sample quenched at 840℃ for 20min and tempered at 650℃ for 3h possesses of high strength （σ＇s =576MPa,σb=835MPa） and good plasticity （85=18.4% ） because of obtaining more round carbides. Also the sample normalized at 1200℃ for 4h and spheroidizing annealed at 800℃ for 2h has higher strength （σs= 622MPa, σb=927 MPa） with slightly low plasticity （δ5=16. 0% ） because of the uniform distribution of fine spherodized carbides in it. Although there is a certain lamellar carbides in the samples annealed at 720℃ for 3.5h,as well as annealed at 840℃ for 10min and then at 720℃ for 2.5h,they have higher strength（σ≥590MPa,σb≥870） and relatively low plasticity（δ5≥11%）.