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系统地研究了灰铸铁Cr-Mo激光合金化层中合金元素的分布、显微组织和耐磨性。试验结果表明,当激光束功率和预涂层合金成分一定时,合金化层的合金浓度主要决定于激光扫描速度。适中的激光扫描速度(7mm/s)下,合金元素在层内分布较均匀,沿层深浓度梯度平缓,合金化层的组织为极细小均匀的树枝晶;其余扫描速度下,表面Cr-Mo浓度高,沿层深浓度梯度大,表面高合金浓度处组织为白亮层,次层为树枝晶和层片状莱氏体,随层深增加枝晶间距增大。Cr-Mo激光合金化显著提高了灰铸铁的硬度和耐磨性。
The distribution, microstructure and wear resistance of alloying elements in gray cast iron Cr-Mo laser alloying layer were studied systematically. The experimental results show that when the power of the laser beam and the composition of the pre-coating alloy are constant, the alloy concentration of the alloyed layer mainly depends on the laser scanning speed. Under moderate laser scanning speed (7mm / s), the alloying elements are distributed more evenly in the layer, and the depth gradient along the layer is gentle. The microstructure of the alloyed layer is extremely fine and uniform dendrites. At the other scanning speed, the surface Cr-Mo The concentration is high, the depth gradient along the layer is large, the white bright layer is formed at the surface high alloy concentration, the dendrite and lamellar ledeburite are formed in the sublayer, and the dendrite spacing increases with depth. Cr-Mo laser alloying significantly improves the hardness and wear resistance of gray cast iron.