What is steel – different types of steel
Steel, also known as ferrous materials, are basic metals including pig iron, ferroalloys, cast iron, cast steel, structural steel, tool steel, stainless steel and heat-resistant steel, etc. as the main elements, and are the most widely used and used metal materials in industry. This article will introduce the different types of steel by different classification methods.
Steel Classification
Steel types can be classified according to the following method:
- Chemical composition,
- Use and application,
- Manufacturing Processing Forms,
- casting methods,
- Metallographic structure, etc.
Different types of steel by chemical composition
Carbon steel
Carbon steel refers to an iron-carbon alloy with a carbon content of less than 2% and containing a small amount of impurity elements such as silicon, phosphorus, sulfur and oxygen. According to their carbon content, these types of steel can be divided into:
- Low carbon steel, also known as iron or mild steel, has a carbon content of 0.04-0.25% (or 0.30%)
- Medium carbon steel, with a carbon content of 0.25 (or 0.30) – 0.60%.
- High carbon steel, carbon content is 0.60-1.25%.
- High carbon steel with a carbon content of 1.25-2.00%
Grades:
- Pure iron, carbon content is ≤0.04%
- Pig iron: carbon content is ≥2.0%
For more information about carbon steel, see Difference Between Low, Medium, and High Carbon Steel.
steel alloy
Alloy steel refers to a steel that is refined based on carbon steel by adding some alloying elements (such as chromium, nickel, molybdenum, tungsten, vanadium, titanium, etc.) to improve the properties of the steel.
According to the type of alloying elements, these types of steel can be divided into:
- Stainless steel
- Chrome steel,
- manganese steel,
- chromium manganese steel,
- chrome-nickel steel,
- chrome molybdenum steel and
- manganese silicon steel, etc.
According to the total content of its alloy elements, it can be divided into:
- Low-alloy steel, the total mass fraction of alloying elements is ≤5%;
- Medium alloy steel, the total mass fraction of alloying elements is 5-10%;
- High alloy steel, the total mass fraction of alloying elements is > 10%.
Classification of Steel by Use and Application
According to use, the classification of steel can be divided into:
- Structural steel
- Tool steel
- Die steel
- Steel spring
- Bearing steel
- Abrasion-resistant steel (wear-resistant steel)
- steel valve
- Cold steel
- Free cutting steel
- steel bridge
- Marine steel
- Boiler steel
- Pressure vessel steel
- Electrical steel, etc.
Classification of Steel by Manufacturing Processing
Hot rolled steel
Hot-rolled steel refers to various steels produced by hot rolling, and most steel is hot-rolled. This type of steel is commonly used to produce steel profiles, steel pipes, steel sheets and wires.
Cold rolled steel
Cold-rolled steel refers to various steels produced by cold rolling. Compared with hot-rolled steel, cold-rolled steel has the characteristics of smooth surface, accurate size and good mechanical properties. This type of steel is commonly used to roll thin sheets and strip steel.
Cold drawn steel
Cold drawn steel refers to various steels produced by cold drawing, which have the characteristics of high precision and good surface quality. This type of steel is mainly used for the production of steel wires, and is also used for the production of round steel and hexagonal bars with a diameter of less than 50 mm and steel tubes with a diameter of less than 76 mm.
Cast steel
Cast steel refers to a steel casting produced by the casting method, and its carbon content is generally between 0.15-0.60%. Due to poor casting properties, steel castings often require heat treatment and alloying to improve their structure and properties. In the mechanical manufacturing industry, cast steel is mainly used to manufacture parts that are complex in shape, difficult to forge or cut, and require greater strength and plasticity.
Forged steel
Forged steel refers to various forged parts produced by the forging method. The quality of forged steel parts is higher than that of steel castings and can withstand large impacts, plasticity and toughness. Other aspects of mechanical properties are also superior to those of steel castings, so for some important parts of the machine, it must be forged steel.
Different types of steel by casting methods
Steel with rim
Edged steel refers to steel that is incompletely deoxidized and produces edge on the ingot during casting. It is characterized by low cost, good surface quality and deep drawing performance, but large composition segregation, uneven quality, low corrosion resistance and mechanical strength. This type of steel is used in large quantities for rolling steel and plain carbon steel sheets.
Dead steel
Dead steel refers to steel that has been completely deoxidized. When pouring, the molten steel dies and there is no boiling phenomenon. These types of steel are characterized by less segregation of components and uniform quality, but at a higher cost. Alloy steel and high-quality carbon steel are generally dead steels.
Half-dead steel
Semi-dead steel refers to steel with a degree of deoxidation between rimmed steel and dead steel. The boiling phenomenon is weaker than that of edged steel during casting. The quality and cost of steel are also between rimmed steel and dead steel. However, their production is difficult to control, so these types of steel do not represent a large proportion of steel production.
