Steel pipe is a hollow steel, a large number of pipes used for conveying fluid, such as oil, natural gas, water, gas, steam, etc., in addition, bending, torsion strength of the same, the lighter weight, so wide Used in the manufacture of mechanical parts and engineering structures. Also used for the production of conventional weapons, barrels, shells and so on.
Classification of steel pipe: seamless steel pipe and welded steel pipe (with pipe) two categories. According to the cross-section shape can be divided into tube and shaped tube, Steel Pipe widely used is a round steel pipe, but there are some square, rectangular, semi-circular, hexagonal, equilateral triangle, octagonal and other profiled steel pipe.
For the pressure of the steel pipe to be carried out by the hydraulic test to test its pressure capacity and quality, under the provisions of the pressure does not occur leakage, Steel Pipe wetting or expansion of qualified, and some steel pipe according to the requirements of the standard or demand side of the curling test , Flaring test, flattening test and so on.
Seamless steel pipe: Seamless steel pipe is made of steel ingot or solid tube through the perforated tube, and then made by hot rolling, cold or cold. The specifications of the seamless steel pipe are indicated by the outer diameter * wall thickness mm. Seamless steel pipe hot rolling and cold rolling (dial) seamless steel pipe two categories.
Hot-rolled seamless steel pipe sub-general steel pipe, low, Steel Pipe medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, geological pipe and other steel pipe.
In addition to the general steel pipe, low pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, other steel pipe, but also include carbon thin-walled steel pipe, alloy thin-walled steel pipe, Stainless steel pipe, shaped steel pipe.
Hot-rolled seamless pipe diameter is generally greater than 32mm, wall thickness 2.5-75mm, cold-rolled seamless pipe diameter can be 6mm, wall thickness to 0.25mm, thin-walled tube diameter to 5mm wall thickness of less than 0.25mm, cold Rolling ratio is higher than that of hot rolling.
General use of seamless steel pipe is 10,20,30,35,45 and other high-quality carbon steel 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other synthetic steel made of hot-rolled or cold-rolled. 10,20 and other low-carbon steel seamless pipe is mainly used for fluid pipeline. 45,40Cr and other carbon steel made of seamless pipe used to manufacture mechanical parts, such as cars, Steel Pipe tractors force parts. General use of seamless steel pipe to ensure strength and flattening test. The hot-rolled steel pipe is delivered in a hot-rolled state or a heat-treated state; the cold-rolled steel is delivered in heat-treated state. Low and medium pressure boiler seamless steel pipe: for the manufacture of various low and medium pressure boilers, Steel Pipe superheated steam pipes, boiling water pipes, water wall pipe and locomotive boiler with superheated steam pipe, smoke pipe, small smoke pipe and arch brick.
Hot-rolled or cold-rolled (welded) seamless steel tubes with high quality carbon structural steel. Mainly made with 10,20 steel, in addition to ensuring the chemical composition and mechanical properties to do water pressure test, curling, flaring, flattening and other tests. Hot-rolled to hot-rolled delivery, cold rolling (dial) to heat treatment delivery.
High-pressure boiler steel pipe: Mainly used to manufacture high pressure and above the pressure of the steam boiler pipe and other high-quality carbon structural steel, Steel Pipe alloy structural steel and stainless steel heat-resistant steel seamless pipe, the boiler tube by the party at high temperature and high pressure work , The tube in the role of high temperature flue gas and water vapor will also occur under the oxidation and corrosion, so the requirements of steel pipe with high lasting strength, high oxidation resistance, Steel Pipe and has good organizational stability, the use of steel: high-quality carbon 12CrGoG, 12CrMoG, 12CrMoG, 12CrMoVG, 12Cr3MoVSiTiB, etc .; rust heat-resistant steel commonly used 1Cr18Ni9,1Cr18Ni11Nb high pressure boiler tube in addition to ensuring the chemical composition and mechanical properties of the steel Outside, to do the water pressure test, to be flaring, Steel Pipe flattening test. The steel pipe is delivered in heat treatment. In addition, the finished steel pipe microstructure, grain size, decarburization layer also has certain requirements. Geological drilling and oil drilling and control of seamless steel pipe; to explore the underground rock structure, groundwater, oil, natural gas and mineral resources, Steel Pipe the use of drilling rig drilling. Oil and natural gas mining is more inseparable from drilling, geological drilling and control oil drilling with seamless steel pipe is the main equipment drilling, including the core of the outer tube, core tube, casing, drill pipe and so on. As the drilling pipe to drill into the depth of several kilometers to work, the working conditions are extremely complex, drill pipe to withstand pull, pressure, bending, Steel Pipe torsion and uneven impact load and other stress, but also by the mud, rock wear and tear, therefore, Must be of sufficient strength, hardness, wear resistance and impact toughness, steel pipe with "DZ" (geology of Chinese phonetic prefix) plus a representative of the steel yield point, commonly used steel DZ45 45MnB, 50Mn; DZ50 40Mn2, 40Mn2Si; DZ55 40Mn2Mo, 40MnVB; DZ60 40MnMoB, DZ65 27MnMoVB. The tubes are delivered in heat treatment.