| 摘要 |
PROBLEM TO BE SOLVED: To increase the hardness and strength of a pin without depending on the change of wire drawing conditions by wire-drawing a wire rod consisting essentially of tungsten into a prescribed shape, subjecting at least one part of the obtd. pin to carbonizing or nitriding and forming a tungsten or tungsten nitride layer. SOLUTION: A wire rod of pure W, dope W, Re-W, Re-Mo-W, platinum clad tungsten or the like is wire-drawn to the wire diameter of 0.05 to 0.7 mm, if required, the tip part is pointed, and its shape is formed into the more bent one. At least one part of the obtd. tungsten series pin, e.g. the tip part is carbonized or nitrided to increase its hardness. This partial treatment can be executed by masking the nonworking part, bringing the working part into contact with carbon powder, ammonia or the like and executing holding at 1000 to 1800 deg.C for 0.5 to 4 hr. In this way, a WC or WN layer is formed on the prescribed part to a thickness of 0.5 to 100μm, by which a high strength tungsten series pin having at least 900 HV hardness and about >=35000 N/mm2 Young's modulus can be obtd.
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