Heat Treating of Tool Steels,Heat Treating of Tool Steels,Heat Treating of Tool Steels,Heat Treating of Tool Steels
TOOL STEELS are high-quality steels made to close compositional and physical tolerances; they are used to make tools
for cutting, forming, or shaping a material into a part or component adapted to a definite use. The earliest tool steels were
simple, plain carbon steels, but beginning in 1868, and to a greater extent early in the 20th century, many complex, highly
alloyed tool steels were developed. These complex alloy tool steels, which contain, among other elements, relatively large
amounts of tungsten, molybdenum, vanadium, and chromium, make it possible to meet increasingly severe service
demands and to provide greater dimensional control and freedom from cracking during heat treating. Many alloy tool
steels also are widely used for machinery components and structural applications where particularly severe requirements
must be met, such as high-temperature springs, ultrahigh-strength fasteners, special-purpose valves, punches and dies,
wear-resistant liners, and bearings of various types for elevated-temperature service. This article discusses procedures and
process control requirements for heat treating the principal types of tool steels. It also provides a review of heat-treating
processes that are applied to tool steels and the specific applicability of these processes to the various types of tool steels.
In service, most tools are subjected to extremely high loads that are applied rapidly. They must withstand these loads a
great number of times without breaking and without undergoing excessive wear or deformation. In many applications,
tool steels must provide this capability under conditions that develop high temperatures in the tool. No single tool material
combines maximum wear resistance, toughness, and resistance to softening at elevated temperatures. Consequently,
selection of the proper tool material for a given application often requires a trade-off to achieve the optimum combination
of properties. Table 1 gives the classifications and nominal compositions of various tool steels.

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