摘要本论文主要研究逆转变奥氏体对17-4PH不锈钢组织和力学性能的影响。首先将17-4PH不锈钢在1040°C下固溶处理30min，然后进行水淬，接着分别进行600°C和650°C的时效处理，时效时间从15min至8h。本实验通过对不同时效处理后的试样进行各项力学性能检测和组织与结构观察达到研究目的。力学性能检测包括：显微维氏硬度测试，拉伸性能测试，冲击性能测试；组织结构观察包括：金相组织观察，扫描电子显微镜，XRD。47086

实验结果表明：随着时效时间的延长，17-4PH不锈钢的硬度和强度逐渐下降。而冲击韧性的变化则比较复杂，随着时效时间的延长，冲击韧性先上升到一个峰值，然后略有降低，接着再次上升，到达又一个峰值后又下降。这是由于时效处理改变逆转奥氏体的含量，使材料的强度硬度降低，而韧性有所上升。

毕业论文关键词：17-4PH不锈钢；时效处理；逆转奥氏体

Abstract

In this thesis, the impact of reverted austenite stainless steel 17-4PH microstructure and mechanical properties. First 17-4PH stainless steel solution treatment at 1040°C 30min, then water quenched, followed by respectively 600°C and 650°C aging treatment, aging time from 15min to 8h. In this study, the sample after aging treatment were different mechanical properties testing and observation of the organization and structure to achieve the purpose. Mechanical properties testing include: micro Vickers hardness testing, tensile properties test, impact performance testing; Observation organizations include: optical microscopy, scanning electron microscopy, XRD.

The results show that: with aging time, 17-4PH stainless steel for strength and hardness decreased. Changes impact toughness is more complex, with the extension of aging time, the first impact toughness rises to a peak, and then decreased slightly, then rise again to reach a peak and then decline. This is due to the reversal of the aging process to change the content of austenite, the strength of the hardness of the material decreases, and increased toughness.

Keywords：17-4PH Stainless Steel；Aging treatment；Reversed austenite

目  录

1  绪论 1

1.1  不锈钢简介与分类 1

1.1.1  铁素体不锈钢 1

1.1.2  奥氏体不锈钢 1

1.1.3  奥氏体-铁素体双相不锈钢 1

1.1.4  马氏体不锈钢 2

1.1.5  沉淀硬化不锈钢 2

1.2  不锈钢的发展和前景 2

1.3  17-4PH不锈钢简介 3

1.4  17-4PH不锈钢存在的问题 5

1.5  课题的意义与目的 5

2  课题方案 6

2.1  实验材料 6

2.2  时效处理 7

2.3  力学性能测试 7

2.3.1  硬度测试 7

2.3.2  拉伸测试 8

2.3.3  冲击测试 9

2.4  X射线衍射测定逆变奥氏体含量 9

2.5  扫描电镜观察材料断口 10

2.6  金相制样和观察 11