摘要本文对钢基体表面双丝堆焊Fe-Al金属间化合物进行了工艺试验。试验中通过钢焊丝和铝焊丝的不同组合、改变预热温度等措施得到了Fe3Al。当主机（JM56钢焊丝）采用焊接电流200A、电弧电压25V、送丝速度为8.0m/min；辅机（5A56铝焊丝）采用焊接电流78A、电弧电压17V、送丝速度为5.0m/min、焊接速度45cm/min，焊前预热温度为350℃时，焊接过程稳定，焊缝成型良好，堆焊层无裂纹、气孔、夹杂、未熔合等缺陷。67696

金相分析试验表明，堆焊层呈现粗大的柱状晶，且柱状晶内部有很多析出的相。硬度试验表明熔覆层的维氏硬度在350HV-450HV范围内，此相为Fe3Al相。

毕业论文关键词  Fe-Al金属间化合物  双丝焊工艺  金相组织  硬度

毕业设计说明书（论文）外文摘要

Title   Study on overlaying Fe-Al intermetallic by double arc welding on the surface of steel   

Abstract

In this dissertation, the overlaying of iron and aluminum intermetallic with steel as base metal was conducted by using double-wire welding process. Problems including cracks occurred in surfacing layer are solved though combination of Fe and Al wires and adjustment preheat temperature. When JM56 steel wire is applied to the master engine with voltage of 25V,current of 200A ,wire feeding speed of 8m/min, while 5A56 aluminum wire to the slave engine ,with the voltage of 17V,current of 78A,wire feeding speed of 5m/min, the welding speed of 45cm/min and preheat temperature of 350℃  ,welding process is stable, the surface layer is shaping with excellent cracking resistance, without inclusion, cracks and non-fusion involved.

Metallographic analysis showed that, the surface layer exhibits coarse columnar crystals with a lot of precipitation phase inside. Hardness tests showed that the cladding layer has a Vickers hardness of 350HV~450HV range , this phase is phase Fe3Al.

Keywords   Fe-Al intermetallic   Twin wire welding   Microstructure   Hardness

目   录

1 绪论 1

1.1 课题研究的内容和意义 1

1.2 Fe-Al金属间化合物 1

1.2.1 Fe-Al合金相图 1

1.2.2 Fe-Al金属间化合物的物理和化学性能 2

1.2.3 Fe-Al合金层的制备方法和局限性 2

1.3 铝与钢异种金属焊接性 5

1.4 Fe-Al焊接的发展现状 6

1.4.1 搅拌摩擦焊 6

1.4.2 激光焊 6

1.4.3 电子束焊 7

1.5 双丝电弧焊 7

1.5.1 双丝电弧焊的原理和特点 7

1.5.2 双丝焊的主要方法 7

1.5.3 双丝焊的应用与发展 8

2 试验设备、材料和试验方案 10

2.1 试验设备 10

2.1.1 TANDEM R450 TOPMAG 自动双丝焊系统 10

2.1.2 金相显微镜 12

2.1.3 数显显微硬度计 13

2.2 试验材料 13

2.3 试验方案设计