堆焊工艺参数与碳化钨含量对镍基碳化钨涂层性能的影响研究

以Ni35复合WC粉末为原料,采用等离子堆焊工艺在Q235A低碳钢表面制备了镍基复合碳化钨涂层,研究了焊接电流、WC含量对复合涂层性能的影响。结果表明,降低堆焊电流,减少热量输入,可以有效防止WC沉积。在研究范围内,WC含量低的样品WC沉积明显,而WC含量高的样品中WC分布较均匀。Ni35复合WC涂层相组成主要为γ-Ni(Cr,Fe)相、γ-(Ni,Fe)基体相,第二相WC,弥散相Cr₃C₂、Cr₇C₃、FeNi₃和W₂C。在焊接电流一定时,随着WC含量增加,堆焊涂层硬度增大;涂层中WC含量相同时,随着堆焊电流降低,涂层硬度上升。在大焊接电流(210 A)下,随着镍基涂层中WC含量增加,样品磨损量逐渐增大;在小焊接电流(195 A)下,随着WC含量增加,样品磨损量降低;当涂层中WC含量相同时,随着堆焊电流降低,样品磨损量降低。

Influence of Surfacing Process Parameters and Tungsten Carbide Content on Properties of Nickel-Based Tungsten Carbide Coatings

With Ni35 composite WC powder as the raw material, a nickel-based composite tungsten carbide coating was prepared on the surface of Q235A low-carbon steel by plasma transferred arc (PTA) process, and the effects of welding current and WC content on the performance of the composite coating were studied. The results show that WC deposition can be effectively prevented by reducing the surfacing current and decrease the heat input. The samples with low WC content has an obvious WC deposition, while the samples with high WC content has more uniform WC distribution. The phase composition of Ni35 composite WC coating mainly consists of γ-Ni(Cr,Fe) phase, γ-(Ni,Fe) matrix phase, the second phase (WC) and dispersed phases (Cr₃C₂, Cr₇C₃, FeNi₃ and W₂C). When the welding current is constant, the hardness of the surfacing coating increases with the increasing of the WC content. When the WC content in the coating is constant, the hardness of the coating increases with the decreasing of the surfacing current. With the high welding current (210 A), the wear loss of the sample gradually increases with an increase in the content of WC in the nickel-basedcoating, while with lower welding current (195 A), the wear loss of the sample decreases with an increase in the WC content. When the WC content in the coating is constant, the wear loss of the sample decreases with the decreasing of the surfacing current.