KV粉末を用いたPPW肉盛溶接金属の特性

概要

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The recent deregulation allows the operators to extend the shutdown maintenance interval from the conventional one year to the maximal 4 years at their petrochemical plants, where the components should withstand the hostile service conditions, high temperature and pressure, and severe erosion and corrosion, more than before. Consequently it gets a crucial technical challenge to achieve greater durability of the components. Plasma Powder Welding (PPW) is an established overlaying process to yield the unrivaled erosion-corrosion resistance. As filler alloy powders for PPW, authors designed Co-Cr-Mo-V system DAPKV series bearing 1 to 4%C and 5 to 17%V, which disperse fine spherical VC carbides in the overlay. Even with higher C contents, they are ready to weld into the multi-layered beads up to 18mm in height, free from cracking without pre-heating. They develop the neat overlays with the RT-800°C hardness and the abrasion and wear resistance both higher than the conventional Co-Cr-W system Stellite series. Most of their mechanical properties are superior to Stellites. Some components overlaid with KV10, 2%C and 9%V, proves their multiplied service lives at refineries and plastic injection shops.