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摘要：本课题通过对15CrMo渗碳缓冷样品进行一次淬火，研究不同淬火温度对其表面渗层以及心部组织及性能的影响。实验选取淬火温度范围为780℃-930℃，保温30分钟油冷。对所有样品进行金相组织分析，并根据国家标准对淬火马氏体组织进行评级，测量文氏硬度。综合金相组织及硬度，分析不同热处理工艺参数对15CrMo钢的影响规律。结果表明，由于淬火温度的不同，钢淬火后组织和性能发生很大的变化。随着淬火温度的升高，心部的铁素体含量减少，铁素体形貌从随机分布的大块状变成弥散分布的小块状；晶粒细小的块状马氏体群变成板条状马氏体。在两相区内随着淬火温度上升，铁素体含量减少，分布更为均匀且细小，硬度升高。超过860℃后铁素体逐渐消失，880℃时硬度出现峰值。表面渗层硬度随着温度升高而升高，880℃以下表面马氏体晶粒没有明显粗化。15CrMo渗碳后最佳一次淬火温度为860℃。40975
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毕业论文关键词： 15CrMo钢；渗碳；一次淬火；金相组织；硬度
Effect of heat treatment process parameters on Microstructure of 15CrMo steel after carburizing
Abstract: In this paper, we study the effect of different quenching temperature on the microstructure and properties of the surface layer, and the microstructure and properties of the 15CrMo steel by means of a quenching process. The quenching temperature range is 780℃-930℃, 30 minutes of heat insulation oil cold. Metallographic structure analysis of all samples, and according to the national standard of quenching martensite organization rating, measuring Vivtorinox hardness. The influence of different heat treatment process parameters on the 15CrMo steel is analyzed by the composite microstructure and hardness. The results show that the microstructure and properties of the steel after quenching are greatly changed due to the different quenching temperature. With the increase of quenching temperature, the content of ferrite in the core decreases, and the shape of ferrite is changed from the random distribution of large block into a small piece of dispersed distribution. With the increase of quenching temperature, the content of ferrite decreases, and the distribution is more uniform and smaller, and the hardness increases. After more than 860℃, the ferrite gradually disappeared, and the peak value appeared at 880℃. The surface hardness of the surface layer increases with the increase of temperature, and the grain size of martensite at 880℃ is not obvious. The best quenching temperature is 860℃ after carburizing for 15CrMo.
KeyWords：15CrMo Steel；Carburization；Primary quenching；Metallographic structure；Hardness
目录
1绪论 1
1.1 15CrMo概况 1
1.1.1化学成份 1
1.1.2相变温度 1
1.1.3热处理规范、性能以及用途 2
1.1.4 15CrMo其他热处理工艺参数 2
1.2 15CrMo钢的生产工艺简介 3
1.3 15CrMo钢合金元素的作用 3
1.3.1钼元素的作用 3
1.3.2铬元素的作用 4
1.4渗碳后的热处理工艺 4
1.4.2一次加热淬火 4
1.4.1直接淬火 5
1.4.3两次淬火 5
1.5渗碳后钢的组织与性能 6
1.5.1渗碳后钢的组织 6
1.5.2渗碳件的性能 6
1.6 15CrMo渗碳钢心部组织对性能的影响 7
1.7 15CrMo钢渗碳淬火后渗层组织对性能的影响及控制 8
1.7.1 15CrMo钢高碳表层组织对性能的影响及控制 8
1.7.2 15CrMo 钢表层与心部的过度区组织对性能的影响及控制 8