Tool steel for hot work

Chemical composition and alloy additives

The range of carbon relative to other tool steels is much lower, within the range of 0.30-0.60%, due to the need to preserve impact strength and material durability, which is supported by Nickel in some grades (eg. WNLV). The most commonly encountered tool steels are Cr-Mo-V, Cr-W-V, Cr-Mo-W-V, Cr-Mo-Co, and Ni-Cr-Mo-V.

Heat treatment of tool steels for hot work

It is necessary to preheat the component to a suitable temperature of 200-250 ℃ in order to preserve the life of the tool steels for hot work, and to properly cool these steels after work.

For the tool life is also responsible proper heat treatment of the product, which is delivered in a softened state. The working temperature of the product should not exceed the tempering temperature. Each of the products is exposed to cracks at work, which over time grows, so it is necessary to replace the components at regular intervals.

Heat treatment of tool steels for hot work consists of multi-stage heating of the product to the austenitization temperature depending on the grade - 850-1150 ℃. The temperature of this compartment must be chosen so that there is no grain growth in the product, which may reduce the ductility of the core of the element.

For smaller sections, hardening is carried out in oil. For larger components, hardening is carried out by spraying water mist, compressed air or with an isothermal stop. The tempering temperature is 500-600 ℃, where the treatment is repeated twice. During tempering, depending on the alloy additives in the grade, M₂C, M₄C₇, M₇C alloy carbides are responsible for the secondary hardness.