退火工艺对SAPH440钢组织和力学性能的影响试题.docVIP

摘要 退火是将钢件加热到适当的温度，根据材料和工件尺寸的不同而采用不同的保温时间，然后进行缓慢冷却的热处理工艺。目的是使金属内部组织达到或接近平衡状态，或者是使前道工序产生的内部应力得以释放，获得良好的工艺性能和使用性能，或者为进一步淬火作组织准备。 完全退火是指将钢件加热到Ac3以上30℃~50℃，经保温完全奥氏体化后，随之缓慢冷却（一般为炉冷），获得近乎于平衡组织的退火工艺。完全退火主要用于压共悉钢的铸件、锻件和热轧型材等，不宜用于过共析钢。 不完全退火是将铁碳合金加热到Ac1~Ac3之间温度，达到不完全奥氏体化，随之缓慢冷却的退火工艺。不完全退火主要适用于中、高碳钢和低合金钢锻轧件等，其目的是细化组织和降低硬度，加热温度为Ac1+(40~60)℃，保温后缓慢冷却。 关键词：退火 热处理 奥氏体 Abstract Annealing is a process which materials are heated to a proper temperature, depending on the material and the size and use of different heat preservation time, and then slow cooling of the heat treatment process. The purpose is to make the metal internal organization in or close to balance, or to release the internal stress caused by the process before, good process performance and use of performance, or for further quenching organization. Refers to the full annealing steel heating to Ac3 above 30 ℃ to 50 ℃, the heat preservation after complete austenitizing, then slowly cooling (generally for furnace cooling), get close to balance the annealing process of the organization. Full annealing is mainly used for pressure of steel castings, forgings and hot rolled profiles, etc., should not be used for hypereutectoid steel. Not completely annealing is to heat the iron carbon alloy Ac1 ~ Ac3 temperature, achieve incomplete austenitizing, then slowly cooling annealing process. Incomplete annealing is mainly suitable for medium and high carbon steel and low alloy steel forged parts and so on, its purpose is to refine the organization and to reduce the hardness, the heating temperature of Ac1 + 40 ~ 60 ℃, slow cooling after heat preservation. Key words：annealing Heat treatment austenitic 目录 摘要 1 绪论 5 1.金属材料的力学性能 6 1.1定义 6 1.2强度 6 1.3塑性 6 1.4硬度 6 1.4.1洛氏硬度 7 1.4.2布氏硬度 7 1.4.3维氏硬度 8 1.5冲击韧度 8 1.6疲劳强度 8 2.铁碳合金的金相组织 9 2.1定义 9 2.2显微组织 9 2.2.1铁素体 9 2.2.1奥氏体 10 2.2.1渗碳体 10 2.2.1珠光体 10 2.2铁碳合金 11 2.3.1铁碳合金的分子构成 11 2.3.2基本概念 12 3.钢的热处理 13 3.1整体热处理 13 3.1.1钢的退火 13 3.1.2钢的正火 14 3.1.3钢的淬火 14 3.1.4钢的回火 15 3.2表面热处理