激光熔覆工艺对铁基合金熔覆层耐蚀性影响的研究

采用不同熔覆工艺进行了铁基粉末的熔覆试验， 结果表明， 随着熔覆功率的增大， 熔覆层组织逐渐变粗大， 耐蚀性下降。 通过腐蚀位置组织结构观察发现， 腐蚀沿晶界从熔覆层表面向内部发展， 并逐渐向晶粒内部发展。 枝晶间的硼化物成分组成改变及碳化物在冷却过程中析出造成基体进一步贫铬， 是熔覆层耐蚀性下降的主要原因。

Corrosion Resistance of Iron-based Alloy Coating by Laser Cladding

Cladding test of iron-based powder was carried out by different processes. The test result shows that the cladding structure gradually becomes coarser with the increasing of cladding power, and the corrosion resistance decreases. By observation of the structure of corrosion location, it is found that the corrosion develops from the cladding surface to the interior along the grain boundary, and then gradually into the grain interior. The change of boride composition between dendrites and the precipitation of carbides during cooling resulting in further chromium depletion in the matrix is the main reason for the deterioration of corrosion resistance of cladding