Definition and classification of tool steels:What is tool steel and different types of tool steel

There is a typical metal tool steel when selecting the best material for  CNC  machining tools. Different kinds of tool steel, which one do you choose? In this paper, the definition and classification of tool steels are introduced, and the characteristics and properties of various tool steels are understood.

What’s the tool steel-tool steel defines tool steel as a special type of carbon steel and alloy steel that is used primarily for tool purposes because of its unique hardness, wear and deformation resistance, and its ability to maintain cutting edges at high temperatures. Tool steels are widely used in cutting, pressing, extruding, machining of metals and other materials.

What are the different types of tool steel? There are six types of tool steels: water quenched, cold worked, impact resistant, high speed, hot worked and special purpose. Thanks to Rohit Kamble, we’ve got four types of tool steel.

Speaking of tool steel, you can identify the type by capital letter.

1. Cold-working tool steel cold-working tool steel is used to cold-work metals below their recrystallization temperature. They have some good hardness and low-temperature wear resistance, but sometimes steel can be used at high temperatures, so at that temperature, we can find that their hardness is relatively low. Cold working tool steels can be divided into the following four types according to the quenching medium.

• water hardened tool steel: must be water quenched, poor hardenability, impact resistance, impact resistance, wear resistance, low cost, used for blanking die, thread die, Hammer, chisel, blade, woodworking tools, knives, etc. .

• oil-hardened tool steel: for forming dies, cutting tools, gauges, etc. , such as O2, with better hardenability, less distortion and less heat treatment shrinkage.

• Air Quenched tool steel: High hardenability, small deformation, good wear resistance, high hardening depth, used for rolling thread, complex die shapes and punches, such as A2.

• HCHC (high carbon high chromium) tool steel: extremely hardenable, hardness and wear resistance, used in forming dies, wire rolling dies, gauges and cutting tools such as D2. The tool can be either oil quenched or air quenched.

2. Hot working tool steel

Hot working tool steel is mainly used for hot working, such as drawing, forming, extrusion, etc. . This kind of tool steel has good strength, toughness, hardness and wear resistance at high temperature. Alloy elements ranging from 0.35% to 0.65% are generally used. Hot working tool steels can be divided into three types according to the principle of allowable elements.

• chromium-type hot working tool steels: for example h10

• tungsten type hot working tool steels: for example h20

• molybdenum type hot working tool steels: for example H41

3. High-speed tool steel

• high-speed tool steel for the temperature can reach 550 °c work, need a certain high hardness, the hardness of this steel can reach a certain high temperature. These steels are widely used for high-speed cutting of metals, for example in numerical control processing, the lathe will use the tool made of high-speed steel. High-speed tool steels are capable of withstanding both compressive and tensile loads. According to the principle of high-speed tool steel, it can be divided into two types.

• Tungsten high speed steel: such as T1

• Molybdenum high speed steel: such as M2

4. Special purpose steel this kind of tool steel is used for special purposes, such as Surface finish, we need high quality Surface finish.

• Type L (low alloy type) : AS L 1, can be used with oil quenched tool steel

• Type F (Carbon Tungsten type: As F 1