Carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip
Carbon structural steel and low alloy structural steel are important structural materials used in construction and mechanical engineering. Because of the important qualities of high strength, good machinability, good plasticity and weldability, and good casting performance, these steels are widely used in engineering production. In different industrial sectors, there are different standards for the type, physical and chemical properties, and dimensional tolerances for the steel used for carbon structural steel and low alloy structural steel.
GB 3274-88 specifies the classification and code, chemical composition, mechanical properties, thickness tolerance, flatness and other technical requirements of carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip.
The mechanical properties and use requirements of carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip specified in GB 3274-88 are specified according to different delivery states, such as hot rolling and annealing, normalizing and tempering etc. For most structures, the delivery state of the hot-rolled steel plate is hot-rolled and annealed. If a certain toughness is required, steel plates of normalizing and tempering state can be selected. The mechanical property requirements of carbon structural steel and low alloy structural steel hot rolled thick steel plate are expressed in the form of yield strength and tensile strength.
The strength of carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip determines its application range, which can be divided into hot-rolled low-strength steel plate, hot-rolled medium-strength steel plate and hot-rolled high-strength steel plate. Structural steels with nominal thickness <10mm are usually all with good hot forming performance and can be used after hot pressing.
The chemical composition of carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip specified in GB 3274-88 is the total mass fraction of each element, including the content of sulfur and phosphorus. Generally, sulfur and phosphorus are harmful components, so their content should be kept as low as possible.
Carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip not only require certain mechanical properties but also require certain requirements on the performance of certain use. In order to ensure the performance of the plate and strip, the test of the impact energy should be carried out. Generally, impact energy requirements are expressed according to different steel grades and different types of plates and strips.
The main technical requirements of GB 3274-88 for the size tolerances of carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip are the thickness tolerances and fundamental tolerance. The tolerance of the products width and length should not exceed the stated tolerances. Usually, the allowable total deformation of steel plates and strips shall meet the requirements of flatness.
Carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip are widely used in engineering, and their mechanical properties, thickness tolerances and flatness tolerance have certain requirements. The requirements of GB 3274-88 should be followed when using carbon structural steel and low alloy structural steel hot rolled thick steel plate and strip, to ensure the quality of products and ensure their safe and reliable use.
