Carbon structural steel
Carbon structural steel is a kind of carbon steel. The carbon content is about 0.05% to 0.70%, and individual can be as high as 0.90%. It can be divided into two types: ordinary carbon structural steel and high-quality carbon structural steel.
There are many uses and a large amount. It is mainly used in railways, bridges, and various construction projects to manufacture various metal components that bear static loads, and unimportant mechanical parts and general welding parts that do not require heat treatment.
Carbon structural steel is a large quantity and wide range of steel materials, accounting for about 70% of steel output.
Low-alloy high-strength structural steel
Low alloy steel is an ordinary alloy steel containing a small amount of alloying elements (the total amount of alloying elements is generally not more than 3%).
This kind of steel has high strength (so called ordinary low-alloy high-strength steel), good overall performance, corrosion resistance, medium temperature resistance, low temperature resistance, and good processing performance, welding performance and other special Performance etc.
High-quality carbon structural steel and alloy structural steel
High-quality carbon structural steel is pure, has less impurities, and has good mechanical properties. It can be used after heat treatment. According to the manganese content, it is divided into two groups: ordinary manganese content (less than 0.80%) and higher manganese content (0.80% to 1.20%). Carbon content is below 0.25%, mostly used directly without heat treatment, or processed by carburizing, carbonitriding, etc., to manufacture small and medium gears, shafts, piston pins, etc. Carbon content is 0.25%～0.60%, typical steel There are 40, 45, 40Mn, 45Mn, etc., which are often quenched and tempered to manufacture various mechanical parts and fasteners. The carbon content exceeds 0.60%, such as 65, 70, 85, 65Mn, 70Mn, etc., which are mostly used as springs. Steel use.
On the basis of carbon structural steel, steel with an appropriate amount of one or several alloying elements (the total content generally does not exceed 5%). This type of steel becomes alloy structural steel.
Due to proper hardenability, after proper metal heat treatment, the microstructure is uniform sorbite, bainite or very fine pearlite, so it has a higher tensile strength and yield ratio (generally in 0.85), higher toughness and fatigue strength, and lower toughness-brittle transition temperature, can be used to manufacture machine parts with larger cross-sectional dimensions.
Special performance steel
Special performance steel refers to steel with special physical and chemical properties. Commonly used are stainless steel, heat-resistant steel, and wear-resistant steel.
Stainless steel refers to steel with high corrosion resistance in corrosive media. According to the different alloying elements, chromium stainless steel and chromium nickel stainless steel are commonly used.
Heat-resistant steel refers to steel with good oxidation resistance and strength at high temperatures. Heat-resistant steel is divided into two types: oxidation-resistant steel and heat-strength steel.
Wear-resistant steel refers to steel with high wear resistance. The carbon content is 1.0% to 1.3%, and the manganese content is 11% to 14%. Because of the high manganese content, it is also called high manganese steel.