Effect of laser scanning speed on microstructure and wear properties of T15M cladding coating fabricated by laser cladding technology

In this paper, a layer of T15M high speed steel alloy powder was deposited on the Q235 substrate surface by laser cladding technology to ensure appropriate scanning speed range serving the production of paper coating scraper. The microstructure of different scanning speeds (100 mm/min, 200 mm/min, 300 mm/min) laser cladding layers was studied by XRD, SEM, EDS and EPMA e.g. the wear properties of the coatings were studied by sliding wear test. The results show that T15M composite coating comprised martensite, retained austenite and carbides. With the increase of the laser scanning speed, more carbides precipitated and large local segregation decreased in the original austenite grain boundary. Defects like pore, microcrack and inclusion existed in the coating. The coating with a scanning speed of 200 mm/min had tiny grain size with high solid solubility compared with the other two coatings. Microhardness of the T15M cladding coating shows the coating with a scanning speed of 200 mm/min possessed higher average hardness in the cladding area while the coating with a scanning speed of 100 mm/min owned the lowest hardness. Sliding wear test indicates that the wear performance of the coating deteriorated and the debris was mass flaking when the laser scanning speed reached 300 mm/min. However, when scanning speed was 200 mm/min, the best wear resistance with obvious plastically deformed furrows occurred.