Ordinary carbon steel
This type of steel is supplied and used in hot-rolled state due to its low carbon content and the absence of other alloying elements. Its yield strength is low, about 200-300 MPa, and its low-temperature toughness is also poor, but its processability is good and its price is low. The most widely used in general engineering structures is A3 steel.
Engineering steel
Low-alloy high-strength steel
Add one or more alloying elements to ordinary carbon steel, and the total amount of alloying elements is generally less than 3%, while the yield strength can be increased to more than 300 MPa. This type of steel has significantly better atmospheric corrosion resistance, wear resistance and low-temperature toughness than ordinary carbon steel, so it can reduce the dead weight of steel structures, extend service life and save power consumption. It is widely used in ships, automobiles, engineering machinery and other aspects. The most commonly used steels are 16Mn, 15MnV, etc. Some low-alloy steels that add elements such as nickel and manganese to improve low-temperature toughness are often used in engineering components in cold areas or low-temperature equipment in petrochemicals, and are called low-temperature steels. Commonly used are 09Mn2V (-70℃), 3.5% Ni (-100℃) steel, etc. Some low alloy steels that add phosphorus, copper, chromium and other elements to improve corrosion resistance are often used in railway vehicles, ships and open-air buildings, etc., and are called atmospheric corrosion resistant steels. Most low alloy high strength steels are used in hot rolled state. After heat treatment, the strength and low temperature toughness of some steels will be further improved, and the yield strength can be increased to 600-1000 MPa. They can be used in important structures that bear high loads such as submarines and high pressure vessels.
High Strength Steel tube
