Tool steel

Tool steel types

Description and features

Tool steels are used for making the tools that are necessary for hot- or cold-working of metallic and non-metallic materials. Due to their high specifications, they are also used in other applications, such as manufacturing precision instruments or highly stressed mechanical components. From a chemical point of view, we can roughly divide them into carbon-only steels and alloy steels.

These steels are generally used in their treated state, and as their purpose is to produce highly stressed parts, they have high carbon contents and/or alloy elements which lead to high hardenability.


The main properties required of  tool steels are:

  • high cutting capacity
  • high resistance to wear toughness under repeated impact
  • thermal shock resistance extreme hardness when hot and/or cold\dimensional stability under heat treatment

In order to guarantee these characteristics, heat treatments must be applied properly and be specifically designed to obtain correct mechanical structures and characteristics.

Tool steel types

From the point of view of classification, there is no uniform system at an international level.

In Italy they are divided into the following categories:

  • Carbon tool steels (1.00-1.30%)
  • Low-alloy carbon tool steels (containing Mn, Cr, Mo, V, W in small quantities)
  • High-speed tool steels where there are significant levels of alloying elements such as chromium, tungsten, vanadium and molybdenum
  • Superfast tool steels, similar to high-speed tool steels but with the addition of cobalt (4-12%) to give greater resistance to wear thanks to the greater hardness that can be obtained.


The classification system based on handling (for example cold or hot) or use (steels for molds) is also in use. The properties of the steels marketed by Siderurgica Lombarda, along with the precise processing procedure, guarantee a product of the highest quality. The range of products consists of various steels in different formats: round, flat, square, angular, hexagonal, tubes, sheets, coils and slabs.