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运用扫描电子显微镜和洛氏硬度计研究了Cr5支承辊用钢不同热处理状态下的显微组织和洛氏硬度。结果表明,调质处理后Cr5钢组织得到明显改善(回火索氏体),细小弥散分布的碳化物取代尺寸较大不规则的碳化物;淬火后试样组织为马氏体,碳化物几乎全部溶入基体,硬度随淬火温度提高而增加(由51.6 HRC增加到58.1 HRC);回火后,Cr5钢中有细小碳化物析出,且弥散分布,淬火温度较高(1050℃、1025℃)时,组织依然保留马氏体结构(回火马氏体),温度较低(1000℃)时,组织为回火索氏体,其硬度与回火前变化趋势相同(由51.4 HRC增加到54.4 HRC)。在所选定的淬火温度下,随着淬火温度的升高,硬度值增大,磨损量减小,磨损严重程度降低,耐磨性较好。
The microstructure and Rockwell hardness of Cr5 steel for backup roller under different heat treatment conditions were studied by scanning electron microscope and Rockwell hardness tester. The results show that the microstructure of Cr5 steel is improved obviously (tempered sorbite) after quenched and tempered, and the carbides with small and dispersed distribution replace the irregular carbide with larger size. The microstructure of the sample after quenching is martensite, and the carbides almost (From 51.6 HRC to 58.1 HRC); after the tempering, fine carbides are precipitated in the Cr5 steel and dispersed and the quenching temperature is higher (1050 ℃ and 1025 ℃) , The structure retained the martensite structure (tempered martensite). When the temperature was low (1000 ℃), the microstructure was tempered sorbite, and its hardness was the same as that before tempering (from 51.4 HRC to 54.4 HRC). In the selected quenching temperature, with the quenching temperature increases, the hardness value increases, the amount of wear reduction, reduce the severity of wear, wear resistance is better.