- What is carbon steel?
Carbon steel is an iron-carbon alloy with a carbon content of 0.0218%~2.11%, also called carbon steel. It usually contains a small amount of silicon, manganese, sulfur, phosphorus and other elements. Different carbon content will cause differences in the performance of carbon steel. Generally speaking, the higher the carbon content, the harder the carbon steel, the higher the strength, but the lower the plasticity.
Carbon steel, also called carbon steel, is an iron-carbon alloy with a carbon content wc less than 2%. The so-called carbon steel refers to steel whose mechanical properties depend on the carbon content in the steel. Generally, a large amount of alloying elements are not added. It is sometimes also called plain carbon steel or carbon steel. In addition to carbon, carbon steel generally contains a small amount of silicon, manganese, sulfur and phosphorus.
According to the carbon content, carbon steel can be divided into high carbon steel, medium carbon steel and low carbon steel.
Low carbon steel has a carbon content of 0.10% to 0.25% and is often used to make chains, rivets, bolts, shafts, etc.;
Medium carbon steel has a carbon content between 0.25% and 0.60% and is often used in building materials and mechanical parts;
High carbon steel has a carbon content from 0.60% to 1.70% and is often used for cutting tools such as drills, taps, reamers, etc., also known as tool steel.
The properties of carbon steel mainly depend on the carbon content. As the carbon content increases, the strength and hardness of the steel increase, while the plasticity, toughness and weldability decrease.
For example, when the carbon content increases, the hardness and strength of the steel increase because carbon atoms combine with iron atoms to form iron carbide. This solid solution strengthening can increase the hardness and strength of the steel. However, an increase in carbon content will also reduce the plasticity and toughness of carbon steel because too many carbon atoms will reduce the gaps between iron atoms, making it more difficult for atoms to slip.
In addition, there are many ways to classify carbon steel. The most commonly used classification is by use, namely carbon structural steel, carbon tool steel and easy-to-cut structural steel. According to the smelting method, carbon steel can be divided into three categories: open-hearth steel, converter steel and electric furnace steel.
According to the deoxidation method, carbon steel can be divided into boiling steel, killed steel, semi-killed steel and special killed steel, which are represented by codes F, Z, b and TZ respectively.
According to the carbon content, carbon steel can be divided into three categories: low carbon steel, medium carbon steel and high carbon steel.
According to the sulfur and phosphorus content, carbon steel can be divided into four categories: ordinary carbon steel with a higher content, high-quality carbon steel with a lower content of phosphorus and sulfur, and high-quality steel with a lower content of phosphorus and sulfur. Finally, there is a special high-quality steel. - Classification of carbon steel
(I) According to carbon content
Low carbon steel: The carbon content in steel is generally less than 0.25%. Low strength, but good plasticity, toughness and welding performance, easy to stamp, can be made into various plates and stamping parts, can also be used to make carburized parts. For example, it is often used to make various plates, can be used to make various stamping parts and containers.
This type of steel is also often used to make various carburized parts. After carburizing and quenching, the steel surface has high hardness and good wear resistance, while the core maintains a certain strength and toughness. It can be used to make parts that bear impact loads and wear-resistant parts, such as gears, short shafts, pins, etc. Therefore, this type of steel is also called surface hardening steel or carburizing steel.
Medium carbon steel: The carbon content in steel is generally between 0.25~0.55%. It has high strength, but low plasticity and toughness. After heat treatment and tempering, it can obtain higher strength and good toughness, and is used to make various shafts, rods and other parts.
This type of steel is generally heat treated and tempered when used. After tempering, it can obtain higher strength and good toughness. It can be used to manufacture various shafts, rods, sleeves, pins, bolts, nuts, etc. If it is quenched and tempered and then surface quenched, the surface can be made hard and wear-resistant, and various wear-resistant parts such as gears, spline shafts, etc. can be manufactured. This type of steel is also called quenched and tempered steel.
High carbon steel: The carbon content in the steel is greater than 0.6%. It has high hardness and strength, but poor plasticity and toughness. After quenching and medium-temperature tempering, it can be used to manufacture springs. This type of steel has high hardness and strength, but poor plasticity and toughness.
If this type of steel is quenched and medium-temperature tempered, it not only has high strength but also good elasticity. It is mainly used to manufacture some springs with low performance requirements. Such as valve springs, leaf springs, spiral springs and spring coils, etc.
(II) Classification by quality
Ordinary carbon steel: high phosphorus and sulfur content.
High-quality carbon steel: low phosphorus and sulfur content.
High-quality carbon steel: lower phosphorus and sulfur content.
(III) Classification by steel product use
Carbon structural steel: mainly used for bridges, ships, building components, machine parts, etc.
Carbon tool steel: mainly used for knives, molds, measuring tools, etc.
Cast steel: used to manufacture parts with complex shapes that require certain strength, plasticity and toughness. For example, gears, couplings, etc.