Sanyo Special Steel Co., Ltd.

Fuji Die Co., Ltd.

Nobuhiro Tsujii

Minoru Mishuku

Nobujiro Tsuchiya

Akira Yamaguchi

Daien Yokoi

Genryu Abe

Disclosed are a cold working tool steel suitable for plastic cold working tools used under severe service conditions, such as forming dies, forming rolls, and form rolling dies, and a process for producing the same. The cold working tool steel has wear resistance and tensile compression fatigue strength and at the same time can provide improved die life. The cold working tool steel is characterized by comprising by weight 0.65 to 1.3% of carbon, not more than 2.0% of silicon, 0.1 to 2.0% of manganese, 5.0 to 11.0% of chromium, 0.7 to 5.0%, in terms of molybdenum equivalent (molybdenum+tungsten/2), of at least one member selected from molybdenum and tungsten, 0.1 to 2.5%, in terms of vanadium equivalent (vanadium+niobium/2), of at least one member selected from vanadium and niobium, and optionally 0.010 to 0.10% of sulfur with the balance consisting of iron and unavoidable impurities, an M.sub.7 C.sub.3 carbide having a grain diameter of 5 to 15 .mu.m being present in a percentage area of 1 to 9%. The process is characterized by comprising the steps of: providing a steel product having the above chemical composition; and tempering the steel product at a temperature of 150 to 500.degree. C., preferably 150 to below 450.degree. C.

Production of cold working tool steel

This invention relates to a method of producing a corrosion-, heat- and wear-resistant member which comprises packing an atomized powder of a high-carbon high-chromium steel into a capsule, heating the capsule packed with the powder, then extruding the capsule packed with the powder to obtain a stock not containing carbide grains greater than 3 .mu.m, working the stock, polishing a surface of the stock, and evaporating a film of TiC and/or TiN onto the polished surface, and further a corrosion-, heat- and wear-resistant member produced by the method. The corrosion-, heat- and wear-resistant member according to this invention is suitable for being members for tools used under extremely severe conditions, such as various tools for can manufacturing, molding tools for reinforced plastics, etc.

Method of producing corrosion-, heat- and wear-resistant member, and the

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Hyogo, Japan

Nobuhiro Tsujii