General Information

It is an alloy or high alloy steel group that is used to turn the raw material into a product by various methods such as cutting, bending, forging, machining or chipless manufacturing of hot or cold work pieces.

GENERAL FEATURES OF TOOL STEELS

We can list the common features expected from all tool steels as follows.

• Clean and homogeneous micro structure,

• High wear resistance,

• High tensile strength,

• Adequate yield strength,

• Adequate ductility,

• High hardness,

• High toughness,

• Homogeneous hardness distribution after heat treatment,

Tool steels are much richer than other steel groups due to their chemical composition, properties, application areas and characteristics expected from them in working conditions. The properties expected primarily from tool and die steels operating under mechanical, thermal, chemical and tribological loads are hardness (hot hardness / strength), wear resistance and toughness. It can highlight some other features such as diversity in use, fatigue and creep resistance, and oxidation and corrosion resistance. All the features expected from the tool steels are that the collective prevents the tool mold from deforming or breaking under working conditions. The material has been developed in the direction of obtaining long life in the lowest possible wear in accordance with the desired properties in the microstructure.

In tool steels, martensitic matrix has been used for a long time and this matrix must be highly hardened due to its carrier function. While the matrix hardness in the quenched state is primarily proportional to the amount of carbon, the role of the carbide-forming elements becomes evident in the tempered state. In practice, optimal application characteristics are obtained by changing the alloying and heat treatment according to the usage temperature. For example, in ledeburitic cold work tool steels (1.2080, 1.2436), a small amount of chrome-rich mixed carbide deposits in the matrix is ​​sufficient for low temperature applications. In high-speed steels operating at high temperatures, sediment hardening is tried to be maximized with mixed carbides rich in molybdenum and vanadium. Likewise, changing the amount of elements such as chrome molybdenum and vanadium in the structure of hot work steels in certain proportions adds properties such as the ability to maintain its hardness at high temperatures and temper resistance.

Tool steels are classified according to their usage areas. All steels are produced with ingot metallurgy, and recently, they have also started to be produced with increasing amounts of powder metallurgical production method. In the alloying of steels, carbide-forming elements are used extensively due to similar purpose. With the use of very different amounts of carbide formers, the amount of carbon varies within a wide range. In addition, nickel and cobalt are added to some steels due to toughness and temper continuity. A common feature of all tool steels is that they are hardened through martensitic transformation. The difference between tool steels comes from the type, amount and distribution of carbide formed by different amounts of alloying elements included in the structure to achieve the expected properties.

Tool steels are collected in four main groups according to their usage areas.

• Hot Work Tool Steels

• Cold Work Tool Steels

• Plastic Mold Steels

• High Speed ​​Tool Steels (HSS)