焊缝缺陷超声定量测试方法研究-无损检测专业毕业论文

焊接缺陷超声定量测试方法研究

摘  要

随着现代工业的发展，对产品质量和结构安全性，使用可靠性提出了越来越高的要求，由于无损检测技术具有不破坏试件，检测灵敏度高等优点，所以其应用日益广泛。用无损检测方法对产品质量进行控制，使之在规定的使用条件下，在预期的寿命内，产品的部件或者整体都不会发生破损，从而防止设备和人身事故。

本文主要叙述在压力容器焊接缺陷安全评定工作中，焊接缺陷的定量分析结果至关重要，尤其是焊缝的裂纹类缺陷和未焊透缺陷。能否用常规无损检测技术较精确的测定压力容器对接焊缝中缺陷的高度，尤其是裂纹类缺陷将直接影响缺陷安全评定工作的可靠性。通过超声波检测方法研究，比较不同检测工艺的特点，制定相应的压力容器对接焊缝缺陷高度的测定方法和工艺，为缺陷自身高度的定量测定提供依据，为安全评定提供有效的缺陷几何尺寸。

关键词：缺陷，超声，定量

Study on ultrasonic quantitative test methods for welding defects

Abstract

With modern industrial development, more and more requirements are put forward to product quality, structure safety and operation reliability. As nondestructive testing (NDT) technology has advantage of not damaged specimen and high sensitivity detection, it has been used widely. NDT methods are used on product quality control and brought it under service conditions and expected life, the parts or overall of products do not damage, and thus the equipment and personal accident are prevented. 

This paper describes welding defects quantitative analysis which is important in the safety assessment work of pressure vessel welding defect, especially in the crack of weld defects and incomplete penetration defects. Whether conventional NDT techniques can more accurately inspect the defect height in the butt weld of pressure vessels, especially crack, it directly affects the reliability of safety assessment work on defects. Through ultrasonic detection methods research, the characteristics of different test procedures are compared, and corresponding test methods and procedures on defect heights are formulated for pressure vessel butt weld. Thus the basis is provided for quantitative determination of welding defect height, and effective defect geometry dimension is provided for safety assessment.

Key words: defects,ultrasonic,quantitative

目   录

1 序言 1

1.1 课题的目的和意义 1

1.2 焊缝的超声波检测 1

2 文献综述 2

2.1 压力容器 2

2.2 焊缝 5

2.3 超声波技术 10

2.4 目前压力容器焊缝缺陷超声定量存在的问题 13

3 焊缝超声波检测工艺 15

3.1 检测准备工作 15

3.2 探测条件选择 20

3.3 扫描速度（时基线比例）的调节 25

3.4 灵敏度的调整和校准 26

3.5 扫查方式的确定 29

3.6 缺陷定位、定量及其定性 29

4 实验内容 35

4.1 检测对象 35

4.2 仪器调节 35

4.3 探头、耦合剂的选择与K值的测量 36

4.4 距离波幅曲线 37

4.5 探头扫查范围及方式 39

4.6 缺陷定位 40

4.7 缺陷定量 40

4.8 缺陷定区域 40

4.9 缺陷测长 40

4.10 缺陷评级 41

4.11 数据记录 42

5 分析讨论 43

5.1 超声波检测与射线检测结果比较 43

5.2 超声波不同探头检测结果比较 43

5.3 超声波检测存在的问题 43