摘要：本论文通过对18CrMnTi钢渗碳样品进行了奥氏体加铁素体两相区、奥氏体单相区不同温度加热淬火，研究了18CrMnTi钢不同淬火温度对样品淬火后心部组织和硬度的影响规律。淬火加热温度为780℃，800℃，820℃，840℃，860℃，880℃，930℃等，加热保温时间为30min，淬火冷却介质为油。实验结果表明，18CrMnTi钢在不同的淬火温度淬火后，组织中出现了马氏体（包括残余奥氏体）、钢的硬度提高。18CrMnTi钢在奥氏体加铁素体两相区加热淬火后，组织为铁素体、马氏体加残余奥氏体，随着淬火温度的升高，铁素体逐渐减少，马氏体不断增多。18CrMnTi钢在超过临界温度Ac3加热淬火后，组织为马氏体加残余奥氏体。18CrMnTi钢单相区加热淬火后，由于随着淬火温度的升高组织中残余奥氏体的不断增加，钢的硬度随着淬火温度的升高而不断降低。62206

毕业论文关键词：18CrMnTi钢；渗碳；淬火温度；金相组织；硬度

After 18CrMnTi steel carburizing quenching temperature on cardiovascular department organization

Abstract：This thesis of 18CrMnTi carburizing steel samples by two phase austenite and ferrite, austenite phase different quenching temperature and studied 18CrMnTi steel quenching samples with different quenching temperature on the middle of the back of the influence law of structure and hardness. Quenching heating temperature is 780 ℃, 800 ℃, 820 ℃, 840 ℃, 860 ℃, 880 ℃, 930 ℃, the heat preservation time for 30 min, quenching cooling medium for oil. The experimental results show that the 18CrMnTi steel after different quenching temperature quenching, martensite has occurred in the organization of residual austenite (including), steel hardness increase. 18CrMnTi two-phase steel in the austenite and ferrite area after quenching, organized into ferrite, martensite and retained austenite, with the increase of quenching temperature, ferrite gradually reduce, martensite growing. The Ac3 of 18CrMnTi steel in more than critical temperature after quenching, organized into martensite and residual austenite. Single-phase area 18CrMnTi steel after quenching, because with the increase of quenching temperature in the organization of residual austenite steel hardness decrease with the increase of quenching temperature.

Key Words：18CrMnTi steel; Carburizing；Quenching temperature;The microstructure; hardness

目 录

1 文献综述 1

1.1 18CrMnTi钢介绍 1

1.1.1 特性及适用范围 1

1.1.2 化学成份 1

1.1.3 相变温度 1

1.2 渗碳 2

1.2.1 渗碳的目的 2

1.2.2 渗碳的工艺 2

1.3 渗碳钢 2

1.3.1 渗碳钢的用途 3

1.3.2 常用钢种 3

1.4 渗后淬火 3

1.4.1 直接淬火 4

1.4.2 一次淬火 4

1.4.3 二次淬火 4

1.5 金相组织 4

1.5.1 马氏体 4

1.5.2 残余奥氏体 4

1.5.3 铁素体 5

1.6 课题的研究现状 5

1.7 课题主要研究的内容 5

1.8 课题的目标 5