摘要
本文研究了渗碳后热处理工艺对18Cr2Ni4WA渗碳钢组织和性能的影响。结果表明:渗碳后油冷并于Ac_1～Ac_3之间淬火,试件心部得到细小的针状F+M复合组织;渗碳后炉冷并于Ac_1～Ac_3之间淬火,心部得到细小的颗粒状F+M复合组织。当淬火温度高于Ac_3时,渗碳后油冷或炉冷试件心部和表层均为粗大的M+A_R。渗碳后油冷再淬火的整体冲击韧性高于渗碳后炉冷再淬火者,特别是在接近Ac_1再淬火时差别更大。随淬火温度降低,炉冷者的整体冲击韧性随之下降;而油冷者变化不明显,并且比渗碳后二次淬火者稍高。试件渗碳后无论经油冷还是炉冷,心部硬度均随淬火温度的降低而下降,而表层硬度先增后降。建议此钢的渗碳热处理工艺采用渗碳后快冷+较低温度下的加热淬火,这样可在保证表层具有高硬度的前提下心部具有较高的韧性,以满足零件服役条件对性能的要求。
The effect of heat treatment process on the structure and properties of carburized steel 18Cr2Ni4WA was studied.When it is quenched from between Ac_1and Ac_3. the structure in the core of the sample oil cooled after carburized is fine, acicular complex of F+M, and that of furnace cooled after carburized is fine, granular complex of F+M.When it is quenched from over Ac_3, the structures in both core and surface of the sample are coarse M+A_R.The gross impact toughness of the sample oil cooled after carburized is much higher than that of furnace cooled, especially when it is quenched from lower temperature.With the temperature decrease from which it is quenched, the gross toughness of the sample furnace cooled decreases rapidly, but that of oil cooled showes only.a little change and is equal to or a little higher than that of twice-quenched after carburized.Whether oil cooled or furnace cooled after carburized, with the temperature decrease from which the sample is quenched, thc hardness of it is core decreases and the hardness of its surface increases at first and then decreascs.For the optimum development of the properties of both the core and the surface of the carburizcd steel, it is sugested that rapid cooling after carburizing and then quenching from lower temerature between Ac_1and Ac_3shoud be engaged in the heat treatment of this carburized steel.
出处
《热加工工艺》
CSCD
北大核心
1990年第3期13-17,共5页
Hot Working Technology
