What are the quality features of nm400 weathering steel
Structural steel for construction is used to build boilers, ships, bridges, workshops and other building materials. This kind of steel usually needs welding construction, so it is generally low carbon steel with carbon content less than 0.25%, which is mostly used in hot rolling or normalizing state. NM400 weathering steel, Structural steel for machinery is used for manufacturing machines or mechanical parts. This kind of steel is often used after carburizing or quenching and tempering. The steel used for carburizing is low carbon steel with carbon content of 0.1% ~ 0.3%. Steel used for quenching and tempering refers to medium carbon steel with carbon content of 0.3% ~ 0.6%.
Beijing machining center has more than 1000 employees, including 360 technicians, 28 engineers, 6 senior welders, 15 professional welders, 52 bachelor's degree, 3 doctor's degree, and 8 R & D team. It is a professional NM400 weathering steel production team combining theory and practice. With an annual output of 80000 tons, looking forward to the future, our company continues to strengthen the advantages of NM400 weathering steel leading suppliers in the four steel fields of steel plate, steel pipe, stainless steel and special steel.
Quenching is a heat treatment process in which steel parts are heated to above the critical temperature, and after proper heat preservation, the parts are quickly cooled to room temperature in water or oil, so that martensite transformation occurs. The hardness of the quenched NM400 weathering steel increases sharply. Quenching is to prepare the organization for adjusting and improving the performance of NM400 weathering steel during tempering, while tempering determines the performance and life of the workpiece.
Composition characteristics of low alloy structural steel, NM400 weathering steel: (1) Low carbon: the carbon content of low alloy structural steel is less than 0.20% due to the high requirements of toughness, weldability and cold formability. (2) The alloy elements such as manganese are added. (3) The addition of Nb, Ti or V and other auxiliary elements: a small amount of Nb, Ti or V forms fine carbides or carbonitrides in the steel, which is beneficial to obtain fine ferrite grains and improve the strength and toughness of low alloy structural steel. In addition, adding a small amount of copper (≤ 0.4%) and phosphorus (about 0.1%) can improve the corrosion resistance. The addition of a small amount of rare earth elements can remove sulfur and gas, purify the steel, and improve the toughness and process performance of low alloy structural steel.
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