铝青铜粉末等离子堆焊层硬度与组织研究

Study on Hardness and Microstructure of Plasma Surfacing Layer of Aluminum Bronze Powder

采用反极性弱等离子弧堆焊方法分别在无磁场和外加横向交流磁场条件下将铝青铜粉末堆焊到锅炉用钢20g母材上。通过硬度试验及金相显微方法,分析了堆焊层的力学性能及组织形貌。结果表明,无磁场作用下,堆焊层的硬度随着堆焊电流的增加而呈"小→大→小→大"变化,当堆焊电流为100A时,硬度值最大,为214.7HV;当堆焊电流为110A时,硬度值最小,为163.7HV。外加磁场作用下,堆焊电流取100 A,堆焊层的硬度在磁场电流为0.5A时达到最大,为245.9HV。堆焊电流为100A时,堆焊层组织为致密的α-Cu和网状结构的(α+γ2),此时为较好的组织结构。

Aluminum bronze power was surfaced on 20 g parent metal using reverse polarity weak plasma arc without magenecic field and with lateral communication magenecic field, and its mechanical properties and microstmcture were analyzed by hardness test and optical microscopy. The results indicate that, with the increase of surfacing current without magnetic field, the hardness of the surfacing changes in the form of ＂low→high→low→,high＂, when the welding current is 100 A, the surfacing layer reaches the maximum hardness （214.7 HV）; when the welding current is 110 A, the surfacing layer reaches the minimum hardness （163.7 HV）. In the magnetic field, the surfacing layer reaches the maximum hardness （245.9 HV） at the surfacing current 100 A and the magnetic current 0.5A. For surfacing current is 100 A, the microstructure of the surfacing layer is compact structure of α-Cu and net structure of α＋γ2.