铸轧辊套表面超高速激光熔覆钴基熔覆层高温耐磨性能

为了提高铸轧辊辊套的使用寿命，采用超高速激光熔覆技术在32Cr3Mo1V铸轧辊辊套表面制备了钴基熔覆层.分析了熔覆层的表面形貌、显微组织及高温摩擦磨损性能，并与优选常规激光熔覆层进行了对比. 结果表明，优选的超高速以及常规激光熔覆层均表面平整，与基体结合良好，无明显裂纹、气孔等缺陷. 超高速激光熔覆层显微组织非常均匀细小，枝晶轴间距极小，很大程度上抑制了枝晶偏析的范围，使得熔覆层的元素分布更加均匀. 在700 ℃高温摩擦磨损试验中，超高速激光熔覆层产生的氧化物磨屑更小，更容易发生团聚效应，有利于釉质层的形成，熔覆层变形量更小，对釉质层进行了有效支撑，出现大面积具有减摩耐磨作用的釉质层，表现出优异的耐高温摩擦磨损性能.

High-temperature wear resistance of Co-based cladding layers by ultra-high speed laser cladding on the surface of the cast-rolling roller sleeve

In order to improve the service life of the cast-rolling roller sleeve, a Co-based cladding layer was prepared on the surface of the 32Cr3Mo1V cast-rolling roller sleeve using ultra-high-speed laser cladding technology. The surface morphology, microstructure, high-temperature friction and wear properties of the cladding layer were analyzed. And which was compared with that of the preferred conventional laser cladding layer. The results show that the preferred ultra-high-speed and conventional laser cladding layers all have a smooth surface and a good combination with the substrate without obvious cracks, pores and other defects. In contrast, the microstructure of the layer by ultra-high-speed laser cladding is very uniform and fine. And the dendrite axis spacing is extremely small, which largely suppresses the range of dendrite segregation. As a result, the more uniform distribution of element was obtained. During the process of 700 ℃ high temperature friction and wear test, the super oxide wear debris produced from the high-speed laser cladding layer is more smaller compared with that of conventional laser cladding layer. Therefore the agglomeration effect is more likely to occur, which is conducive to the formation of the enamel layer with anti-friction resistance. As the same time, the deformation of the layer by ultra-high-speed laser cladding is smaller, which has more effectively support for the enamel layer, consequently a large area enamel layer can be obtained. Thus the ultra-high-speed laser cladding layer exhibits excellent high-temperature friction and wear resistance.