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针对激光相变强化搭接带存在的回火软化等问题,对激光强化的球墨铸铁材料QT700-2搭接区的显微硬度、表面粗糙度、物相变化等进行了测试,并分析了强化机理。结果表明:选用合理的搭接率等工艺参数,球墨铸铁激光搭接强化后的硬度可达到50HRC以上,调节搭接宽度可以避免搭接区的回火软化问题。多道搭接强化后表层的马氏体组织呈区域性交错分布,材料表面形成非均匀、多尺度强化结构,强化后的表面具有良好的耐磨性和耐疲劳性。通过上述结果,对材料激光搭接强化的工艺参数进行了合理的优化。
Aiming at the problems of temper softening and other problems existing in the laser phase transition strengthening lap tape, the microhardness, surface roughness and phase change of laser strengthened ductile iron material QT700-2 are tested and the effects of strengthening mechanism. The results show that the hardness of ductile iron can be over 50HRC after laser lap bonding by adjusting the parameters such as reasonable lap rate and so on. Adjusting lap width can avoid the problem of temper softening in lap area. After lapped and strengthened, the martensite microstructure of the surface shows a regional staggered distribution, the surface of the material forms a non-uniform and multi-scale reinforced structure, and the strengthened surface has good wear resistance and fatigue resistance. Through the above results, the process parameters of laser lap bonding were optimized reasonably.