Cold work tool steels

High-C high-Cr cold work tool steels 1 2.25 12 ... 

For tool steels, a letter followed by one or two numbers. For example, D2 belongs to a family of high carbon, high chromium tool steels known as cold work tool steels. All members of this family have the prefix D. 

Groups O, A and D are cold work tool steels and are the most popular groups of tool steels. They have moderate-high... 

Lima JG, Avila RF, Abrao AM, Faustino M, Davim JP (2(X)5) Hard turning AISI4340 high strength low alloy steel and AlSl D2 cold work tool steel. J Mater Process Technol 169 388-395... 

Thyrodur, Cold work tool steel, Thyssen Specialty Steels, Inc. 

Oil-hardening cold-work tool steels 0 Oil-hardening cold-work tool steels are expensive but can be quenched less drastically than water-hardening types. 

In this study we investigated the tribological performance of ZrN and a new Zr(21% Hf)N coatings deposited on hardened AISI D2 cold work tool steel by (he PVD technique. 

Quenched and tempered AISI D2 cold work tool steel discs (28 mm diameter and 10 mm height) were used as substrate materials. The hardness of die discs were 59 HRC. ZrN and Zr(21% Hf)N coatings were deposited on substrates by a PVD technique after final polishing with a l)jm diamond paste. The process parameters of PVD technique are listed in Table 1. 

Too much cold working hardens steel, and harder steel cracks more easily than soft. Perhaps some of our knives, the cracked ones, were overworked by an overzealous hammer operator, or perhaps they were stamped too hard by a super-patriot. Another source of cracks could have been a slip of the polishing wheel or serration cutter or any such tool capable of introducing a nick or nucleus from which a fatigue or other type of crack could get a head start and grow prematurely. Or the knives may have been cooled unevenly or too rapidly, and this could have left residual manufacturing stresses in the blade. 

In very hard tool steels, for example, cold work steels tempered at low temperature, the wear resistance is originated mainly by hypereutectoid carbide which is not affected by hardening. These carbides are very small and evenly distributed and very hard (heavy-duty... 

Hot working causes plastic deformation to occur at a temperature high enough to prevent the material from becoming strain hardened. Instead, it spontaneously recovers plastic deformation. Hot-worked materials therefore do not have the internal energy characteristic of cold-worked materials. In practice, hot-work threshold temperatures are dictated by factors such as tool life. These temperatures range from as low as 350°F (175°C) for aluminum alloys to as high as 23(X)°F (1260°C) for steels and nickel alloys. 

Air-hardening medium-alloy tool steels (cold worked) A Air-hardening medium-alloy tool steels are best suited for applications such as machine ways, brick mold liners, and fuel-injector nozzles. The airhardening types are specified for thin parts or parts with severe changes in cross section, i.e., parts that are prone to crack or distort during hardening. Hardened parts from these steels have a high surface hardness however, these steels should not be specified for service at elevated temperatures. 

Natsume, Y., Muramatsu, T., Miyamoto, T. Effect of carbide crack on fatigue strength of alloy-tool steel under cold working. In Proceedings of JSME Meeting (900-86), 323-325 (1990)... 

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