What is tool steel?

Tool steel is the workhorse of the industrialized world. This highly versatile material is a carbon steel with a relatively high carbon content, usually between 0.7% and 1.5%. Tool steel is alloyed with different metals. Tool steel properties depend to a large extent on the proportions of steel alloy elements such as chromium, vanadium, molybdenum, tungsten, cobalt, or nickel.

The alloying composition in combination with heat treatment, results in an almost limitless variety of carbon steel grades. Depending on the application, the steels are targeted at abrasion resistance, impact toughness, machinability, ability to be polished, shock resistance, or high temperature performance as the most important criteria.

Tool steel grades are used as parts of machines making other parts, and as the produced parts themselves. High machinability is generally a top priority for machine parts, whether it is tool holders, sprocket wheels, gears, gear racks, cutting tools, knife supports, or guide rails – applications for machine components in tool steel are found in all manufacturing industries. 

Tool steels are also widely used for molds and dies, either for cold stamping and punching, or casting or forging at a high working temperature. The yield strength, wear resistance and impact toughness of premium tool steels remain higher than conventional hot work steels also at elevated temperatures. Uses ot tool steel also include all kinds of plastic injection molds.

One category of modern tool steel is pre-hardened. This means the steel has already undergone a quenching and tempering process at the steel mill and will not be subjected to any further heat treatment after machining the steel to its final dimensions. 

There are several advantages to using a pre-hardened carbon steel. A traditional tool steel is comparatively soft and needs heat treatment after machining to reach sufficient hardness. 

This heat treatment can cause the steel part to change shape and dimension, requiring further machining to reach the correct measurements. Both the additional heat treatment and machining are costly and time-consuming procedures, which can be avoided by using a pre-hardened steel which will resist deformation.

The properties of tool steel are to a large extent depending on the steel alloy components. Tool steels are commonly divided into these categories:

• W-type is a water-hardening tool steel. It’s a widely used low carbon steel because of its low cost compared to other tool steels. The steel alloy content makes it a high-alloyed steel.
• Cold-work type tool steels are used for larger parts or parts where only minimal distortion during hardening is allowed. Tool steels in the cold work category include oil hardening and air hardening steels.
• D-type tool steel or hot work tool steel is a high carbon steel that keeps its hardness up to temperatures as high as 425 °C (800 °F) and is used for forging dies and die casting.
• S-type tool steel is designed to resist shock at both low and high temperatures and is used, for example, in jackhammer bits to ensure the cutting edge stays intact.
• T-type and M-type tool steels are used for cutting tools where strength and hardness must be retained at temperatures up to or exceeding 760 °C (1400 °F). T-type is regarded as a high alloy steel, same with M-type.
• H-type is low carbon steel developed for strength and hardness when exposed to elevated temperatures for long periods.

All production environments are challenged to produce fast and with high quality. The high hardness and toughness of Toolox^® tool steel allows it to meet these challenges.

Toolox^® is prehardened steel with high machinability, which saves time when manufacturing steel components. It also ensures that the final products deliver maximum performance, productivity and service life without the need for heat treatment after processing. This steel’s surface hardness which gives high wear resistance extends into the core of the material.

Toolox^® engineering and tool steel from SSAB is mainly used for all kinds of machine components or molds and dies for hot and cold applications.

Leading Argentinian medical equipment manufacturer Innovos achieves 100 percent customer satisfaction with Toolox^® 33. “Using Toolox^® 33 in the majority of our projects allows us to reduce production times, reduce tool wear and save time in after-treatment.” CEO Gustavo Becker, Innovos.