16mn钢焊接研究.doc

16Mn钢焊接研究

包括外文翻译

摘   要

16Mn钢是具有高强度、高韧性和耐腐蚀等优良特性的低合金高强钢，是我国低合金高强钢中用量最多、产量最大的钢种，广泛用于制造桥梁、船舶、车辆、锅炉、高压容器、输油输气管道、大型钢结构等。鉴于16Mn钢在我国工业和国民经济建设中的重要性，而16Mn钢的焊接又是16Mn钢应用中必不可少的一道工艺技术,因此16Mn钢的焊接进行研究对实践应用意义重大。本课题采用焊条电弧焊对16Mn钢进行焊接，分析焊接接头的组织和性能的变化；并对得到的焊接接头进行正火处理，分析热处理前后焊接接头组织和性能的变化。

结果表明，焊接接头焊缝区组织为柱状晶；熔合区为粗大晶粒；过热区为魏氏组织；完全结晶区为细小的铁素体和珠光体；不完全结晶区一部分为细小的铁素体和珠光体，一部分为粗大的铁素体。由于熔合区粗大晶粒和过热区魏氏组织的存在使得16Mn钢焊接接头可能存在冷裂纹和热影响区脆化等缺陷。所以对其进行焊后正火处理，热处理后的焊接接头晶粒明显比未热处理过的要细小，组织结构更加均匀。硬度也相应的有所升高。因此，热处理可以改善焊接接头的组织，并提高其性能。

本课题研究的16Mn钢焊条电弧焊工艺、焊接接头组织和性能以及焊后热处理工艺可为实践生产中16Mn钢的焊接提供参考。

关键词：16Mn钢；焊条电弧焊；焊接接头；组织和性能；热处理

Welding Research of 16Mn Steel

Abstract

16Mn steel is a low alloy high strength steel which has high strength, high toughness and corrosion resistance and other excellent characteristics. It has the largest amount and the largest steel production among the low alloy high strength steel in China. It is widely used in manufacture of bridges, ships, vehicles, boilers, pressure vessels, pipelines, large steel structure. In view of the importance of 16Mn steel in ours industry and national economy, also 16Mn steel welding is an essential technology, so the welding of steel 16Mn study is significant for practical application. In this issue 16Mn steel was welded by SMAW, the changes welded joint were analyzed in the organization and performance; welded joints were obtained by normalizing processing, and analyzed the changes of the organization and performance between before and after heat treatment.

The results show that the weld zone is the columnar crystal; fusion zone is coarse crystal; hot area is the widmanstatten structure; completely crystalline region is the ferrite and pearlite; one part of incomplete crystalline region is the small Ferrite and Pearlite, another is the coarse Ferrite. The coarse crystal of the 16Mn steel welded joint fusion zone and the widmanstatten structure of the 16Mn steel welded joint hot area as the result of Cold cracking and HAZ. So it was processed by normalizing after welding, welded joints after heat treatment were significantly higher than the grain is not heat treated to small and more uniform structure. Hardness was increased accordingly. Therefore, heat treatment of welded joints can improve the organization and improve its performance. 

Research of 16Mn steel's SMAW, microstructure and properties of welded joints, heat treatment after welding can be used as a reference of the welding of 16Mn steel in practice.

Keywords: 16Mn steel; electrode arc welding; welded joint; microstructure and properties; heat treatment

目    录

引  言 1

第1章  绪  论 2

1.1  背景与意义 2

1.2  发展概况 2

1.3  来源与内容 3

第2章  焊接理论知识 4

2.1  焊接性及其实验评定 4

2.1.1  焊接性及影响因素 4

2.1.2  焊接性评定原则及方法 5

2.2  焊接接头及组织和性能 7

2.2.1  焊接接头的概念 7

2.2.2  焊接接头的基本形式 8

2.2.3  焊接接头的设计要求 10

2.2.4  坡口的基本形式 10

2.2.5  焊接接头特性 11

2.3  焊条电弧焊 13

2.3.1  焊条电弧焊概述 13

2.3.2  焊接设备及辅助工具 13

2.3.3  焊条电弧焊基础 16

2.3.4  焊条电弧焊工艺参数 18

2.3.5  焊条电弧焊的基本操作技术 19

2.3.6  常见的焊条电弧焊缺陷及防治措施 21

第3章  实验过程 22

3.1  16Mn的焊接 22

3.1.1  16Mn钢简介 22

3.1.2  16Mn钢的焊接性 23

3.1.3  16Mn钢的焊接工艺参数 23

3.2  金相试样的制备、观察及其硬度测试 25

3.2.1  金相试样的制备 25

3.2.2  金相试样的观察 26

3.2.3  试样的硬度测试 26

第4章  实验结果分析 28

4.1  焊接接头金相组织分析 28

4.1.1  焊缝区 28

4.1.2  熔合区 28

4.1.3  过热区 29

4.1.4  完全结晶区 29

4.1.5  不完全结晶区 30

4.1.6  母材 31

4.2  焊接接头硬度分析 31

结论与展望 34

结论 34

展望 35

致    谢 36

参考文献 37

附录A 引用的英文资料及翻译 38

附录B 主要参考文献及摘要 47