Influence of buffer layer on surface and tribomechanical properties of laser cladded Stellite 6

Wear resistance coatings of Stellite 6 were deposited on SS316 substrate by blending a buffer layer of Inconel 625 with varying Linear Heat Inputs (LHI). The mechanical and microstructural properties of Stellite 6 coatings are investigated to evaluate the effect of buffer layer. The surface flaws, microstructure, micro-hardness and wear resistance of Stellite 6 clads with buffer layer are studied and compared with direct deposited Stellite 6. The results show an increment in clad height by 30% and 9% at lower and higher LHIs, respectively as compared to pre-deposited Stellite 6 clads. The deposition pattern (with and without buffer) are free from surface and internal cracks. The dilution is reduced by 25% and 10% whereas the microhardness shown an improvement by 12% and 5% with addition of buffer layer. Further, a fine-grain microstructure is observed in buffer layer clads at the interface zone. Moreover, the studies on wear rate have shown improvement of 14% and 3%, respectively with low coefficient of friction (COF) in buffer layer deposition because of high microhardness and fine grain microstructure. Thus, laser cladding of Stellite 6 at lower LHI with buffer layer has shown excellent mechanical and microstructural properties.

Automated summary

The research found that laser cladding of Stellite 6 on SS316 substrate with a buffer layer of Inconel 625 at lower Linear Heat Inputs demonstrated excellent mechanical and microstructural properties, showing higher microhardness and finer grain microstructure. Moreover, the addition of buffer layer contributed to reduced dilution, improved microhardness, and increased wear resistance.