Tool steels: characteristics and uses

Tool steels constitute an essential category of materials used in industries ranging from the automotive and aerospace sectors to the production of industrial equipment and precision instruments. Characterised by exceptional mechanical properties and wear resistance, tool steels are essential for the production of tools and components requiring high performance and durability. Tool steel is characterised by its high content of carbon and alloying elements, which combine during heat treatment to create carbides that give the material its hardness and strength characteristics.

In the context of ATP Europe‘s activities, the protective coatings offered by the company play a key role in ensuring the performance and longevity of tool steels, protecting them from oxidation and decarbonisation during machining operations and throughout their operational life cycle. To fully understand the importance of these coatings, it is essential to take a closer look at the characteristics and uses of tool steels.

Types of tool steels

Tool steels are divided into different categories according to their chemical characteristics, mechanical properties, specific applications and according to the metal processing they undergo. 

Tool steels for hot working

Hot machining, which involves high temperatures during the machining process of metallic materials, requires tool steels specially designed to maintain high mechanical performance under extreme conditions. Tool steels for hot machining are designed to resist plastic deformation, oxidation and thermal fatigue, ensuring form stability and machining precision.

These tool steels intended for hot machining must maintain high mechanical performance even at high temperatures, often exceeding 600°C. They are alloyed with elements such as chromium, molybdenum and tungsten, which provide resistance to thermal deformation and oxidation.

To withstand the high forces and thermal stresses during hot machining, tool steels must be tough to resist cracks and fractures. High temperatures during hot machining promote the oxidation process of steels, which can compromise their performance and tool life. Therefore, this type of tool steel is often coated with protective materials, such as those offered by ATP Europe, or oxidation-resistant alloys to prevent the formation of damaging surface layers.

Hot-working tool steels are widely used in industries such as metal forging, die casting, metal rolling and metal drawing, where high temperature resistance and tool life are critical to the success of the production process.

Tool steels for cold working

Cold working involves handling metal materials at or slightly above room temperature, requiring tool steels that can withstand mechanical stress without permanent damage.

Essential for cold-worked tool steel is a high degree of hardness, which is necessary to withstand cutting, bending, shearing and punching without suffering deformation or excessive wear. This hardness is achieved through targeted heat treatment and the addition of alloys such as tungsten, vanadium and molybdenum.

Abrasion resistance is also crucial considering the direct contact with the machined material during cold working operations. This resistance is achieved through the addition of carbides and other abrasive materials to the chemical composition of the tool steel.Cold-work tool steels are used in a variety of industries, including the production of automotive components, electronics, household appliances and tools.

High-speed steel: what is HSS and what does it mean?

High-speed steels, commonly referred to as HSS, which stands for ‘High-Speed Steel‘ in English, are a category of tool steels designed to cope with high-speed machining with high mechanical performance. These materials are specially formulated to maintain their hardness, toughness and wear resistance even at high temperatures and during cutting, milling, drilling and turning operations performed at high speed.

Their chemical composition includes elements such as tungsten, molybdenum, vanadium and cobalt, which help to improve the mechanical and thermal properties of high-speed steels, enabling them to withstand intense stresses and maintain their shape even under extreme working conditions.

HSS high-speed steels also include cutting tool steel, essential for the production of high-performance tools, widely used for its reliability and versatility in high-speed machining.

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Powder Tool Steels

Powder tool steels are an advanced category of materials used for the production of high-performance tools. Obtained through a powder metallurgy process, these steels involve a finely controlled mixing of metal powders, followed by a sintering process. This process creates compact components with a homogenous and finely dispersed microstructure.

This microstructure contributes to increased tool wear resistance, toughness and fatigue strength. The presence of carbides and other components dispersed in the microstructure gives powder tool steels greater wear resistance than conventional steels. In addition, powder tool steels are characterised by high density, which contributes to improved mechanical strength and tool life.

The powder metallurgy process also offers greater flexibility in the design of tool steels, resulting in components with complex and detailed shapes, ideal for customised applications and improving performance and productivity. Due to their advanced properties and ability to be customised for specific applications, powder tool steels have become a preferred choice for high-precision and high-reliability applications such as in industries such as automotive, aerospace, electronics and energy.

Protective coatings for tool steel

In the context of tool steel production, the application of protective coatings is crucial to ensure tool life, performance and precision. In particular, for tool steels destined for high-temperature machining, ATP Europe’s protective metal coatings play an indispensable role in protecting the base material from oxidation and decarbonisation, which can compromise the mechanical properties of tools.These coatings are designed to adhere firmly to the tool surface, forming a protective layer that shields the base material from reactive gases present during hot machining operations. This results in increased efficiency and productivity of machining operations, as well as reduced maintenance and tool replacement costs. In addition, protective coatings for tool steel can improve the quality of machined surfaces, reducing the risk of surface defects and improving the surface finish of machined parts.