... hardening depth should moderate.2. HRC should meet with request, guide way hardening can’t deformation.3. heating speed should faster.4 ... . drill bit, coal drill bit, pick bit’s welding5. braze lathe tool, milling cutter and all kinds of wooden cutters, braze ... , pin.3. hardening the industrial of machine tool, such as : bed guide way of machine tool.4. heat treatment pliers, spanner, screwdriver, drill ...