Application of carbon steel
This type of steel can be smelted by oxygen converter, open hearth furnace or electric furnace, and is generally hot rolled into steel plates, steel strips, profiles and bars. Steel plates are generally delivered in the state of hot rolling (including controlled rolling) or normalizing treatment. The chemical composition, tensile properties, impact energy and cold bending properties of the steel shall comply with the relevant regulations. In the Chinese national standard GB700-88, this type of steel is divided into 5 grades according to the value of the yield point, and divided into 4 grades according to the quality. Its brand name is composed of four parts in order: the letter Q representing the yield point, the value of the yield point, the quality grade symbol, and the deoxidation method symbol. This type of steel has a wide range of applications, most of which are used as welded, riveted or bolted steel structures, and a few are used to make various machine parts. Q195 and Q215 steels with lower strength are used to make low-carbon steel wire, steel wire mesh, roof panels, welded steel pipes, anchor bolts and rivets, etc. Q235 steel has medium strength, good plasticity and toughness, and is easy to form and weld. This kind of steel is mostly used as steel bars and steel structural parts, and also used as rivets, railway spikes and various mechanical parts, such as bolts, tie rods, connecting rods and so on. Q255 and Q275 steels with higher strength are used to make various agricultural machinery, and can also be used as steel bars and railway fishplates. According to the special performance requirements of some industrial steels, the composition of ordinary carbon structural steels is slightly adjusted to form a series of professional steels, such as rivet steel, bridge steel, pressure vessel steel, hull steel, and boiler steel. In addition to strictly controlling the chemical composition and ensuring the general performance of steel for professional use, some special inspection items are also stipulated, such as low temperature impact toughness, aging sensitivity, gas in steel, inclusions and fractures.
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