锅炉水冷壁CMT堆焊技术

发布时间：2018-06-24 13:28

本文选题：冷金属过渡焊 + 锅炉水冷壁　；参考：《沈阳理工大学》2017年硕士论文

【摘要】：本文主要针对锅炉水冷壁由冲蚀磨损和高温腐蚀等原因造成的磨损减薄甚至爆管的问题,采用冷金属过渡(Cold Metal Transfer,CMT)焊方法在Q235钢板基体上堆焊了ER-310奥氏体不锈钢堆焊层,系统地研究了堆焊工艺,并对堆焊后的微观组织及力学性能进行了分析。试验结果表明:(1)CMT堆焊优化的工艺参数为焊接电流118A、焊接电压14.2V、焊接速度2.4mm/s、摆动宽度12mm、摆动速度26mm/s、搭接量7mm。能获得成形美观的多道连续的310不锈钢堆焊层,堆焊层无气孔、裂纹等宏观缺陷,厚度约为3mm。(2)堆焊层无气孔、裂纹、未熔合等缺陷,由近表层的等轴细晶区、近熔合区的柱状晶区和中部的混合晶区组成,堆焊层组织为奥氏体;堆焊层中主要有Fe、Cr、Ni三种元素,其含量在堆焊层与基体的结合界面处发生较大变化;堆焊层的稀释率为8.78%;堆焊层硬度在190HV~200HV之间;堆焊后渗透检测合格的弯曲试样均能弯曲到180°不出现开裂,堆焊层塑性良好。堆焊层具有良好的耐腐蚀性能。(3)与优化的MIG堆焊工艺相比,CMT堆焊工艺凸显出堆焊热输入量低、堆焊后试板变形量小、堆焊层稀释率低、堆焊层塑性好、耐腐蚀性能高等一系列的优点。(4)CMT堆焊工艺适用于Q235钢板及20G锅炉管,其堆焊层与基体的结合强度在400MPa以上。
[Abstract]:In this paper, aiming at the problems of erosion wear and high temperature corrosion caused by erosion and high temperature corrosion of boiler water wall, cold metal transfer CMT welding method was used to weld ER-310 austenitic stainless steel surfacing layer on Q235 steel substrate. The technology of surfacing welding is studied systematically, and the microstructure and mechanical properties of surfacing welding are analyzed. The results show that: (1) the optimized parameters of CMT surfacing welding are welding current 118A, welding voltage 14.2 V, welding speed 2.4 mm / s, wobble width 12 mm, swinging speed 26 mm / s, lap amount 7 mm. A multi-channel continuous surfacing layer of 310 stainless steel with beautiful shape can be obtained. The surfacing layer has no porosity, crack and other macroscopic defects. (2) the surfacing layer has no porosity, crack, no fusion and so on, from the equiaxed fine-grained zone near the surface layer. The microstructure of the surfacing layer is austenite, and there are three main elements in the surfacing layer, the content of which changes greatly at the interface between the surfacing layer and the substrate, and the composition of the columnar crystal zone near the fusion zone and the mixed crystal zone in the middle of the surfacing zone is austenitic, and there are three main elements in the surfacing layer. The dilution rate of the surfacing layer is 8.78, the hardness of the surfacing layer is between 190HVand 200HV, and the bending specimen which is qualified for penetration test after surfacing welding can bend to 180 掳without cracking, and the surfacing layer has good plasticity. (3) compared with the optimized MIG surfacing technology, the CMT surfacing technology shows that the heat input of the surfacing welding is low, the deformation of the test plate after the surfacing welding is small, the dilution rate of the surfacing layer is low, and the surfacing layer plasticity is good. (4) CMT surfacing welding process is suitable for Q235 steel plate and 20G boiler tube, and the bonding strength between the surfacing layer and the substrate is more than 400MPa.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG455

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