4 Types of Steel: What Makes Them Different?

There are various categories of steel depending on processing, application, composition, and other differentiating factors. Each of these steel has unique properties - composition, percentage of carbon, processing techniques, etc. However, all of these are significant in their respective arenas of application. While some of these are good for household work, others are preferred for heavy industrial duty. A wide division of steel includes four broad types of steel – High-speed steel, Hot work steel, Cold work steel, and Plastic mould steel. Steel can also be differentiated based on water hardening, air hardening, oil hardening, etc. Furthermore, steel can also be divided into four completely different categories, such as – Carbon steel, Stainless steel, Alloy steel, and Tool steel. 

Here are the details about High-speed steel, hot work steel, Cold work steel, and Plastic mould steel.

1. High-speed steel – As the name rightly suggests, high-speed steel has the efficiency to cut metals and other objects at a much faster pace compared to conventional high-carbon steel. This is mainly due to the exceptional features of HSS. Hardness, resistance against wear and abrasions, resistance against melting or softening at high temperatures, etc. make this steel a favorite of Tool steel suppliers. The heat treatment used during the manufacturing procedure of high-speed steel ensure its hardenability and robustness. It also has a high percentage of alloy, such as – molybdenum, vanadium, chromium of cobalt. One noteworthy factor is that – depending on the type of alloy present, the grades of high-speed steel differ. For instance – chromium helps in increasing hardenability and also reduces the chances of oxidation damage while the steel undergoes heat treatment. Each of these alloys contributes a special feature to HSS. It has a high percentage of carbon, with a minimum of 0.65% by weight. Rockwell hardness is 64 at room temperature. This is used for tool bits, saw blades, broaches, taps, drills, milling cutters, etc. 

2. Hot work steel – Tool Steel Suppliers advise using hot work steel for extrusion, pressure die casting, drop forging, and glass and tube product manufacturing. Tools that are made from hot work steel can withstand high temperatures. These can also tolerate fluctuations in thermic loads which occurs when hot work steel comes in close contact with other materials. Hot work steel has excellent resistance against shocks, and deformation at high temperatures while the steel is at work, heat checking, heat treating deformation, outstanding machinability, etc. H-group steel has low carbon content and medium alloy content. Depending on the grades, the properties slightly vary along with the percentage of that particular alloy – tungsten, chromium, or molybdenum. 

3. Cold work steel – As opposed to hot work steel, cold work steel has a higher percentage of carbon and a lower percentage of alloys. However, the low percentage of alloys ensures hardenability, and lesser distortion and permits oil quenching. These are popularly used for collets, gauges, forming dies, and various types of blanking. Metal in cold work steel is shaped and made into a suitable size below its re-crystallization temperature. This process is in direct contrast with hot working procedures such as – welding, hot rolling, or forging. Cold work steel uses techniques such as – shearing, bending, drawing, and squeezing. Cold work steel is robust and stuff but carries chances of being brittle. It can also be used for making flat sheets, riveted joints, screw heads, etc.

4. Plastic mould steel – One of the highly praised steels by Tool Steel Suppliers, plastic mould steel is widely recognized due to its excellent dimensional stability while heating, wear resistance, robustness, good luster, etc. Few grades of plastic mould steel provide extra resistance against corrosion to make them perfect to mould chemically strong plastics. Most types of plastic mould steel are sold in pre-hardened form. This is popularly used in industries like – tool manufacturing and mechanical engineering, blow moulds, injection moulds, press brake dies, etc.

While one may seem superior to the other, each of these steel variants has unparalleled applications across various industries.