摘要：本课题研究了淬火-回火（Q-T）热处理工艺对17 -4P H不锈钢力学性能及组织的影响。实验中对17-4PH不锈钢进行1040℃水冷淬火处理，冷却后再对其进行600℃和650℃不同保温时间的回火热处理。热处理完成后通过光学显微镜观察了实验钢的显微组织；然后通过硬度测试，拉伸试验，冲击试验测试了热处理后试样的力学性能；结果表明，随着回火保温时间的延长，17-4PH不锈钢的强度和硬度逐渐下降；而冲击韧性的变化则不同，会先上升到一个峰值然后下降，之后再次上升。其主要是由于回火处理会产生逆转变奥氏体以及析出不同沉淀相使得试样强度硬度降低，韧性增强。并且通过计算得出其在650℃保温4h的热处理工艺下的抗拉强度和冲击韧性的极值最大。80544

毕业论文关键词：17-4PH不锈钢；淬火-回火；逆转变奥氏体

Study on Heat Treatment Process of 17-4PH Stainless Steel

Abstract: in this paper, the effects of quenching-tempering (Q-T) heat treatment on the mechanical properties and microstructure of 17-4P H stainless steel were studied。 In the experiment, 17-4PH stainless steel was subjected to water cooling and quenching at 1040℃, cooled and then subjected to tempering heat treatment at 600℃ and 650℃for different holding time。 After the heat treatment, the microstructures of the experimental steel were observed by optical microscope。 The mechanical properties of the samples after heat treatment were tested by hardness test, tensile test and impact test。 The results showed that with the annealing time, 4PH stainless steel strength and hardness gradually decreased; and the impact of toughness changes are different, will first rise to a peak and then decline, and then rise again。 Which is mainly due to tempering treatment will produce reverse austenite and precipitation of different precipitation phase makes the hardness of the sample reduced hardness, toughness increased。 And the maximum value of tensile strength and impact toughness under the heat treatment process at 650 ℃ for 4 h was calculated。

Keywords: 17-4PH stainless steel；quenching - tempering；Reverse austenite

目  录

1 绪论 1

1。1 不锈钢概况 1

1。1。1 不锈钢的定义 1

1。1。2 不锈钢的分类 1

1。1。3 不锈钢的发展和前景 1

1。2 沉淀硬化不锈钢 2

1。3 马氏体沉淀硬化不锈钢 3

1。4 17-4PH不锈钢 3

1。4。1 17-4PH不锈钢组织结构和性能 4

1。4。2 17-4PH钢的合金元素对性能的影响 4

1。4。3 17-4PH不锈钢的缺陷 5

1。5国内外研究概况 5

1。5。1 国外17-4PH 不锈钢(ASTM)的发展概况 5

1。5。2 国内17-4PH 不锈钢发展概况 5

1。6 Q-T工艺 6

1。7 课题的意义及研究内容 6

1。7。1 选题目的 6

1。7。2 研究内容 7

2 实验材料与方案 8

2。1 实验材料 8

2。2 实验路线及方案 8

2。3 观察测试