摘要本次堆焊使用的焊丝是无渣自保护药芯焊丝，药芯中加入各种合金金属的粉末， 各合金成分会对最终的焊缝组织、夹杂和气孔产生不同的影响。本文主要针对铁基含 Mn 堆焊焊缝中的组织和夹杂物进行研究，通过对焊缝试样进行金相制作、金相显微 观察、扫描电镜、硬度测试等试验，确定堆焊中不同锰含量对组织形态、夹杂物的分 布和特征，以及夹杂物对焊接接口硬度、组织的影响。83347

对试验结果进行观察和分析显示，锰在一定程度上可以对焊缝进行脱氧，减少其 他金属氧化产物的夹杂，以及降低焊缝的气孔敏感性。随着锰的逐渐加入，脱氧反应 进行的越来越彻底，焊缝中的含氧量将会很明显的下降，并且含氧夹杂物也将大幅度 的减少。对于焊缝组织，含锰量越高，形成的 M7C3 化合物将会越来越规则，由马氏 体和少量奥氏体组成的共晶组织分布越来越均匀，不会出现大块的共晶组织。随着锰 的加入，含氧量降低，有利于焊缝硬度的提高，但是随着含锰量的增加，共晶组织将 会增多且呈网状分布，所以，锰含量 0%~6%对焊缝硬度有一定的增大，大于 6%将会 出现硬度下降，但是增大和减小的幅度不大。

毕业论文关键词：堆焊； M7C3； 含氧夹杂物； 金相； 夹杂物行为

Abstract The welding wire used in this welding is no slag self-protection flux cored wire， Powder to add some kinds of alloy metal to the core。 The composition of each alloy will have different effects on the final weld microstructure, inclusion and porosity。 In this paper, the microstructure and inclusion of Mn in the iron base are studied。 By means of metallographic  examination,  metallographic  observation,  scanning  electron microscope,

hardness test and so on。 The distribution and characteristics of microstructure and inclusion of different manganese, and the influence of inclusions on the hardness and microstructure of welding interface content in surfacing。

The results of the observation and analysis, to some extent, manganese can weld deoxygenation, and reduce other metal oxidation products inclusions, and reduced stomatal sensitivity to weld。 With the addition of manganese gradually, deoxygenation reaction is carried out more thorough, the oxygen content of the weld will be very significant drop, and will be greatly reduced oxygen-containing inclusions。 For weld, higher manganese content, M7C3 compound formed will be more rules, eutectic structure consists of martensite and a small amount of austenite distributed more evenly and will not appear chunk eutectic organization。 With the addition of manganese, reduce the oxygen content, help to improve the hardness of the weld, but with the increase of manganese content, the eutectic structure will increase the distribution and reticulation。 So, a manganese content of 0% to 6% increase in hardness of the weld has some, it will be greater than 6% decrease in hardness, but increased and decreased slightly。

Key words: welding; M7C3; oxygen-containing inclusions; microstructure; inclusions behavior

目录

第一章 绪论 1

1。1  研究课题的背景和意义 1

1。2  国内和国外的研究现状 2

1。2。1  堆焊的概述 2

1。2。2  夹杂物的研究现状 5

1。2。3 Fe-Cr-C 耐磨合金研究进展 6

第二章 试验材料和试验方法