Non-alloy carbon tool steels
|Steel grades for shallow and deep hardening|
|C70W1 - 1.1520 - C70W2 - 1.1620 - U7A - U7|
|C80U - C80W1 - 1.1525 - U8A - U8|
|C90U - 1.1535 - C85W - 1.1830 - U9A - U9|
|C105U - C105W1 - 1.1545 - C105W2 - 1.1645 - U10A - U10|
|U11A - U11|
|U12A - U12 - C120U - 1.1555 - C125U - 1.1563|
Steel grades for shallow and deep hardening - specification
They are defined as the first basic, simple tool steels that have appeared on the metallurgical market. They were used for simple tools, knives, blades, as well as for low-speed cutting tools for low-speed machining - for example, for woodworking, paper processing, or stone processing.
It is also popular to use them as tool steel for files, saws, chisels, gaiters, cutters and hammers. Due to the simple chemical composition consisting of carbon and alloyed additives - Silicon and Manganese, carbon tool steels are characterized by relatively low hardness, low tempering temperature (above 200 ℃ visible hardness decrease), but quite high surface hardness - about 62 HRC , and considerable ductility of the untreated core.
Heat treatment of carbon tool steel
They are an unofficial subgroup of tool steel for cold work. They are suitable for small cross-section tools working at low temperatures. Heat treatment consists of hardening the steel to a temperature range of 770-810 ℃ and water cooling, and tempering at 180-300 ℃ by cooling in air with heating for 2 hours.
Heat treatment requires carefulness despite the simple chemical composition. In the carbon tool grades we distinguish between continuous and hypoeutectoid steel, deep- and shallow-hardened steels.
Application of carbon tool steel
Shallow-hardened tool steels are used for components and sub-assemblies of smaller cross-sections up to 20mm, which after treatment should maintain the softness and ductility of the core. The ductility after hardening is conducive to the use of workpieces exposed to impacts and shocks. In terms of purity of composition, they have a low content of sulfur, phosphorus and other dopants. They show little sensitivity to overheating.
The deep-hardening tool steels are used for products with much larger dimensions, where there is mainly pressure. The ductility of these steels is considerably lower due to the deeper quenched surface of the product. They show more sensitivity to overheating. Applicable to tools with dimensions exceeding 20mm.
It should also be mentioned that non-alloy steels have been partially replaced by cold work tool steels, but for many applications, especially for smaller cross sections, are still used and are not only as good as alloy steels in terns of such properties as hardening larger components, and maintaining hardness at higher temperatures.
We supply carbon steel tools in the form of sheets, cold rolled tapes, bars, forgings and steel plates.