淬火温度对30Cr15Mo1N高氮轴承钢组织和性能的影响

Influence of austenitizing temperature on microstructure and mechanical properties of high nitrogen bearing steel 30Cr15Mo1N

利用金相显微镜、扫描电镜、Thermo-Calc热力学软件、洛氏硬度仪和冲击试验机等研究了淬火温度对高氮轴承钢30Cr15Mo1N组织和力学性能的影响规律。结果表明,随着淬火温度升高,钢中析出相(M_(23)C_6和M_2N)逐渐溶解,基体中元素分布趋于均匀。在淬火温度低于1 050℃时,原始奥氏体晶粒未明显长大,高于1 050℃后晶粒急剧长大。随着淬火温度的升高,硬度先升高后降低,在1 000℃淬火后硬度最高。经低温处理后,30Cr15Mo1N的硬度明显提高,且并未发生显著降低。在900℃淬火后高氮轴承钢30Cr15Mo1N的冲击韧性最佳,而1 000及1 100℃淬火后韧性大幅度降低。

The effect of austenitizing temperature on the microstructure and mechanical properties of high nitrogen bearing steel 30Cr15Mo1N was investigated by means of optical microscope,scanning electron microscope,Thermo-Calc calculation,hardness and impact energy measurements. The results show that with the increment of austenitizing temperature,precipitates（M_（23）C_6 and M_2N）in the steel gradually dissolve and the distribution of elements in the matrix tends to be uniform. There is no significant difference in the prior austenite grain size when the austenitizing temperature is lower than 1 050 ℃. However,when the samples are austenitized at higher temperatures,the austenite grains grow up sharply.The hardness of 30Cr15Mo1N increases with the increment of austenitizing temperature,then decreases when the temperature is above 1 000 ℃. The hardness of the steel is remarkably improved after subzero treatmentand does not decline significantly with the increment of austenitizing temperature. The impact toughness of 30Cr15Mo1N is the best when austenitizing at 900 ℃,and it is greatly reduced after austenitizing at 1 000 and 1 100 ℃.