堆焊层数对D707堆焊层组织性能的影响

Effects of Surfacing Layers on Microstructure and Property of D707 Cemented Carbide Surfacing Layer

采用D707耐磨堆焊焊条在低碳钢Q235A上进行平板堆焊实验,利用光学显微镜及HRS-150的数显洛氏硬度计,研究堆焊层数与堆焊金属组织、性能的关系.实验结果表明:D707焊条堆焊层的组织为Fe3W3C、针状马氏体和残余奥氏体,热影响区组织晶粒细小,分布均匀.堆焊一层、二层、三层的硬度值分别为61.07HRC、62.97HRC、63.07HRC,随着堆焊层数的增加,基体对熔敷金属的稀释率逐渐减小,堆焊层组织中碳化物比值增高,硬度值及耐腐蚀性随堆焊层数增加有所提高,但堆焊层数再增加时,硬度值及耐腐蚀性不再提高.

In this paper, by using the optical microscope and HRS--150 digital display Rockwell Hardness Tester, and choosing the D707 wear-resistant overlaying welding electrode on low carbon steel Q235 flat surfacing welding experiments by manual arc welding method, effects of changing the number of layers on the microstructure and properties of deposited deposited metal are studied. The experimental results indicate that： the microstructure of deposited metal surfacing after welding is Fe3 W3 C, acicular martensite and retained austenite for D707, heat affected zone group small grains and uniform distribution. The hardness of one-layer, two-layer and three-layer surfacing are 61.07HRC, 62.97HRC, 63.07HRC, and the time of point-etching is 3 min, 5 min, 6 min. With the increasing of the surfacing layers, the matrix of the deposited metal dilution rate decreases ; the carbide precipitate more from D707 deposited metal organization, too,and also the hardness and corrosion-resistance has a trend to increase. But when the number of surfacing layers increases, hardness and corrosion resistance are not significantly improved.