| 摘要 |
A replaceable bit for a circular saw is provided with a cutting portion of hard metal alloy by machining off the original cutting portion, supporting the remaining base metal portion such that a predetermined selected part extends into a chill mold, melting the surface of the selected part using a plasma arc welding torch, feeding a rod of the hard alloy into the plasma jet of the torch such that melted material from the rod drips into the mold cavity to fill it, the melted alloy mixing with the melted surface of the selected part of the remaining base metal portion in a transition zone, allowing the melted mass of hard alloy to cool and harden into a dome shape in the mold cavity, removing the bit from the mold cavity, and grinding the flank, face and back regions of the new cutting portion to selected final dimensions. Apparatus suitable for performing the process is disclosed.
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