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摘要：本课题通过对30CrMoSiA中碳结构钢的淬火温度及保温时间的实验，研究了30CrMoSiA在两相区，高温区以及常规温度下淬火和不同的保温时间对淬火组织及硬度的影响。淬火温度设计温度为780℃，820℃，860℃，900℃，940℃，980℃，1020℃保温25min，油冷。保温时间设计为900℃保温5min,10min,15min,20min,25min油淬。淬火后进行组织观察及洛氏硬度检测。结果表明，随着淬火温度的升高，钢中铁素体含量减少，直至900℃时铁素体完全消失，淬火温度超过940℃后，奥氏体晶粒开始发生长大。硬度曲线上出现了两个峰，在AC3临界温度820℃淬火时第一次出现硬度峰值43HRC，这是由于钢中残留的未溶铁素体颗粒抑制了奥氏体晶粒的长大，淬火后得到了较细的马氏体。在900℃淬火出现第二个峰值47HRC，这是由于铁素体完全消失，淬火后能得到完全马氏体，马氏体晶粒细小均匀。30CrMoSiA的最佳淬火温度为900℃。43780
毕业论文关键词： 30CrMoSiA钢；淬火温度；保温时间；金相组织；硬度
Study on the relationship between the quenching process and the microstructure and properties of medium carbon steel
Abstract：This topic based on carbon constructional 30CrMoSiA steel quenching temperature and holding time of experiment, studying the 30CrMoSiA steel in the two-phase region, high temperature and normal temperature quenching and different holding time on structure and hardness of quenching influence.The oil quenching temperature is 780℃，820℃，860℃，900℃，940℃，980℃，1020℃ and heat insulation for 25 minutes.The heat preservation time is designed to 5min, 10min, 15min, 20min, 25min and oil quenching under 900℃.After quenching test microstructure observation and Rockwell hardness.The results show that with the increase of quenching temperature, the content of ferrite decreases and ferrite disappears completely at 900℃.When the quenching temperature exceeds 940 ℃, the austenite grain begins to grow.There are two peaks in the hardness line graph.In the AC3 critical temperature 820℃ quenching for the first time of the peak hardness 43HRC. This is because the residual ferrite particles in the steel inhibit the growth of austenite grains, and the finer martensite after quenching.The 47HRC is the second peaks in the quenching of 900℃.This is due to the complete disappearance of ferrite, the quenching can be completely martensite, fine and uniform grains.The optimum quenching temperature of 30CrMoSiA is 900℃.
Key words： 30CrMoSiA steel,Quenching temperature，Holding time，Metallographic structure，Hardness
目 录
1 绪论 1
1.1 30CrMoSiA钢概况 1
1.2 传统淬火工艺 1
1.3 淬火新工艺 2
1.3.1 高温淬火工艺 2
1.3.2 亚温淬火工艺 3
1.3.3 零保温淬火工艺 3
1.4 合金元素在30CrMoSiA中的作用 4
1.4.1 Cr元素在30CrMoSiA中的作用 4
1.4.2 Mo元素在30CrMoSiA中的作用 4
1.4.3 Si元素在30CrMoSiA中的作用 5
1.5 典型中碳结构钢淬火组织与分析 5
1.5.1 40Cr淬火组织与分析 5
1.5.2 35CrMo淬火组织与分析 7
1.5.3 30CrMnSi淬火组织与分析 8