Engineering steel

Engineering steel can be divided into ordinary carbon steel and low alloy high strength steel two categories.

Steel used to make engineering structures that bear loads, also known as building structural steel. The main requirement for the performance of this type of steel is to have sufficient strength to ensure that there is no permanent deformation and damage during use. In addition, this type of steel often needs to be cut, bent, riveted and welded during use, so it also requires good formability and weldability. The carbon content of this kind of steel is generally less than 0.30%, mostly rolled into a certain cross-section shape of steel (such as Angle steel, channel steel, I-steel, rebar, etc.), steel plate and steel pipe to use, often used in ships, vehicles, containers, lifting and transportation machinery and other engineering structures, in construction engineering is used to manufacture Bridges, steel columns, steel beams, trusses and so on.

Low-alloy high-strength steel adds one or several alloying elements on the basis of ordinary carbon steel, the total amount of alloying elements is generally below 3%, and the yield strength can be increased to more than 300 mpa. The atmospheric corrosion resistance, wear resistance and low temperature toughness of this kind of steel are significantly better than ordinary carbon steel, so it can reduce the weight of steel structure, extend the service life and save power consumption, widely used in ships, automobiles, construction machinery and other aspects of the most commonly used steel 16Mn, 15MnV and so on. Some low-alloy steel with nickel, manganese and other elements to improve low-temperature toughness is often used in engineering components in cold regions or low-temperature equipment in petrochemical industry, called low-temperature steel. Commonly used 09Mn2V (-70℃), 3.5%Ni(-100℃) steel and so on. Some low-alloy steel with phosphorus, copper, chromium and other elements to improve corrosion resistance is often used in railway vehicles, ships and open-air buildings, said atmospheric corrosion resistant steel. Most of the low-alloy high-strength steel is used in the hot-rolled state, and some of the strength and low-temperature toughness will be further improved after heat treatment, and the yield strength can be increased to 600 ~ 1000 mpa, which can be used for important structures such as submarines and high-pressure vessels that bear high loads.

Ordinary carbon steel This kind of steel is supplied and used in hot rolled state because of its low carbon content and no other alloying elements. Its yield strength is low, about 200 ~ 300 mpa, low temperature toughness is also poor, but the process is good and the price is low. The most widely used in general engineering structures is A3 steel.