Carbon steel is the earliest and most used basic material in modern industry. In the industrial countries of the world, cut off disc for stainless steelwhile striving to increase the output of low-alloy high-strength steel and alloy steel, they also pay great attention to improving the quality of carbon steel and expanding the variety and scope of use.
At present, the output of carbon steel is about 80% of the total steel output of various countries. It is not only widely used in construction, bridges, railways, vehicles, ships and various machinery manufacturing industries, but also in the modern petrochemical industry. And marine development, etc., have also been used in large quantities.
Carbon steel is mostly smelted by oxygen converter and flat furnace, and high quality carbon steel is also produced by electric arc furnace. According to the degree of deoxidation in the steelmaking process, carbon steel can be divided into killed steel, boiling steel and semi-killed steel between the two. The effect of the smelting method on the properties of the steel is mainly due to the purity of the steel. People can obtain higher purity steel through vacuum treatment, refining and injection technology, which significantly improves the quality of carbon steel.
The plastic working process of carbon steel is usually divided into thermal processing and cold working. After hot working, defects such as small bubbles and looseness in the ingot are welded together to make the structure of the steel dense. At the same time, thermal processing can destroy the as-cast microstructure and refine the grains. The wrought steel has better mechanical properties than the as-cast state. The cold-worked steel increases in strength and hardness as the degree of cold plastic deformation increases, and the ductility and toughness decrease. In order to improve the yield, the continuous casting process is widely used.
According to the quality of steel, it can be divided into ordinary carbon steel and high quality carbon steel.
(1) Ordinary carbon structural steel, also known as ordinary carbon steel, has a wide limit on carbon content, performance range, and phosphorus, sulfur and other residual elements. cut off disc for stainless steel,In China and some countries, according to the guarantee conditions of delivery, it is divided into three categories: Class A steel (A steel) is steel that guarantees mechanical properties. Class B steel (B steel) is a steel that guarantees chemical composition. Special steel (C steel) is a steel that not only guarantees mechanical properties but also ensures chemical composition, and is often used to manufacture more important structural parts. China currently produces and uses the most A3 steel (Group A steel) with a carbon content of about 0.20%, which is mainly used for engineering structures.
Some carbon structural steels also add trace amounts of aluminum or niobium (or other carbide forming elements) to form nitrides or carbide particles to limit grain growth, strengthen steel, and save steel. In China and some countries, in order to meet the special requirements of professional steel, the chemical composition and properties of ordinary carbon structural steel are adjusted, thus developing a series of professional steel for ordinary carbon structural steel (such as bridges, buildings, Steel for steel bars and pressure vessels, etc.).
(2) Compared with ordinary carbon structural steel, high-quality carbon structural steel has a lower content of sulfur, phosphorus and other non-metallic inclusions. According to the carbon content and the use, these steels are roughly divided into three categories: 1 is less than 0.25% C is low carbon steel, especially 08F, 08Al, etc. containing less than 0.10% carbon, due to good depth It is widely used as a deep-drawing part such as a car, a can, etc. for squeezing and weldability. 20G is the main material for the manufacture of ordinary boilers. In addition, low carbon steel is also widely used as a carburized steel for machinery manufacturing. 20.25~0.60%C is medium carbon steel, which is used in the state of quenching and tempering to make parts of machinery manufacturing industry. 3 is greater than 0.6% C for high carbon steel, mostly used in the manufacture of springs, gears, rolls and so on. According to the difference of manganese content, it can be divided into two groups of ordinary manganese content (0.25-0.8%) and higher manganese content (0.7-1.0% and 0.9-1.2%). Manganese can improve the hardenability of steel, strengthen ferrite, and improve the yield strength, tensile strength and wear resistance of steel. The label "Mn", such as 15Mn, 20Mn, is usually added after the grade of the steel containing high manganese to distinguish it from the normal manganese content of carbon steel.