Seamless steel tubes are made by punching steel ingots or solid billets and then hot rolled, cold rolled or cold drawn. The specifications of the
Seamless Steel Pipe are expressed in terms of outer diameter*thickness mm.
Seamless Steel Tube is divided into hot-rolled and cold-rolled (dial) seamless steel tubes. Hot-rolled seamless steel tubes are divided into general steel tubes, low- and medium-pressure boiler steel tubes, high-pressure boiler tubes, alloy steel tubes, stainless steel tubes, petroleum cracking tubes, geological steel tubes, and other steel tubes. Cold-rolled (dial) seamless steel pipes include general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, as well as carbon thin-walled steel pipes and alloy thin-walled steel pipes.
Stainless Steel Pipe, special-shaped steel pipe. The outer diameter of hot-rolled
Seamless Pipe is generally greater than 32mm, wall thickness is 2.5-75mm, the outer diameter of cold-rolled seamless steel pipe can be up to 6mm, the wall thickness can be up to 0.25mm, and the outside diameter of thin-walled pipe can be up to 5mm, and the wall thickness is less than 0.25mm. Rolling has higher dimensional accuracy than hot rolling.
General seamless steel pipes are made of low alloy structural steels such as 10#, 20#, 30#, 35#, 45#, high-quality carbon steels such as 16Mn, 5MnV, or 40Cr, 30CrMnSi, 45Mn2, 40MnB, and other hot-rolled or cold-rolled steels. Rolled into. The seamless pipes made of low carbon steel such as 10# and 20# are mainly used for fluid transportation pipelines. 45, 40Cr and other medium carbon steel seamless tubes are used to make mechanical parts, such as parts for cars and tractors. Generally used 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 a heat-treated state.
Hot-rolled seamless steel tubes, as the name implies, have a high rolling temperature, so the deformation resistance is small, and a large amount of deformation can be achieved. Taking steel plate rolling as an example, the thickness of the continuous cast slab is generally about 230 mm, and after rough rolling and finish rolling, the final thickness is 1 to 20 mm. At the same time, due to the small aspect ratio of the steel plate, the dimensional accuracy requirements are relatively low, and the problem of plate shape is not easy to occur, and the convexity is mainly controlled. For the requirements of the organization, it is usually achieved by controlled rolling and controlled cooling, that is, controlling the open-rolling temperature, finish rolling temperature and curling temperature of the finish rolling to control the microstructure and mechanical properties of the strip.
Seamless steel pipe execution standard
[1] Seamless pipe for structural use (GB/T8162-2008) is a seamless steel pipe for general structure and mechanical structure.
[2] Seamless steel pipe for fluid transportation (GB/T8163-2008) is a general seamless steel pipe used to transport fluids such as water, oil, and gas.
[3] Seamless steel tubes for low and medium pressure boilers (GB3087-2008) are high-quality carbon structural steels for the manufacture of low- and medium-pressure boiler superheated steam pipes, boiling water pipes, superheated steam pipes for boilers and locomotive boilers for various structures. Hot rolled and cold drawn (rolled) seamless steel tubes.
[4] Seamless steel tubes for high pressure boilers (GB5310-2008) are high-quality carbon steel, alloy steel and stainless heat-resisting seamless steel tubes for the heating surface of water-tube boilers for the production of high pressure and higher pressures.
[5] High-pressure seamless steel tubes for chemical fertilizer equipment (GB6479-2000) are high-quality carbon structural steel and alloy steel seamless pipes suitable for chemical equipment and pipelines with an operating temperature of -40 to 400°C and a working pressure of 10 to 30 Ma. .
[6] Seamless steel pipe for oil cracking (GB9948-2006) is a seamless steel pipe for furnace tubes, heat exchangers and pipes in petroleum refineries.
[7] The geological drilling steel pipe (YB235-70) is a steel pipe used by the geological department for core drilling, and can be divided into drill pipes, drill collars, core pipes, casings, and sedimentation pipes according to applications.
[8] Diamond core drilling seamless steel pipe (GB3423-82) is a seamless steel pipe used for drilling of diamond cores, core rods, and casing.
[9] Oil drilling pipe (YB528-65) is a seamless steel pipe used for thickening or thickening at both ends of oil drilling. The steel pipe is divided into two types, namely the sub-car wire and the non-car wire, and the wire pipe is connected with the joint. The butt welding method of the wire car pipe is connected with the tool joint.
[10] Carbon steel seamless steel tubes for ships (GB5213-85) are carbon steel seamless tubes for the production of Class I pressure piping systems, Class II pressure piping systems, boilers and superheaters for ships. Carbon steel seamless steel pipe wall temperature does not exceed 450 °C, alloy steel seamless pipe wall temperature exceeds 450 °C.
[11] The seamless steel pipe for automobile half-axle casing (GB3088-82) is a high-quality carbon structural steel and alloy structural steel hot-rolled seamless steel pipe used in the manufacture of automobile axle casing and drive bridge axle shafts.
[12] The high-pressure fuel pipe for diesel engines (GB3093-2002) is a cold-drawn seamless steel pipe for the high-pressure pipe of a diesel injection system.
[13] Precision inner diameter seamless steel tubes for hydraulic and pneumatic cylinders (GB8713-88) are precision-drawn or cold-rolled precision seamless steel tubes with precision inner diameter dimensions for the manufacture of hydraulic and pneumatic cylinders.
[14] Cold-drawn or cold-rolled
Precision Seamless Steel Pipe (GB3639-2000) is a cold drawn or cold-rolled precision seamless steel pipe used for mechanical structures and hydraulic equipment with high dimensional accuracy and good surface finish. The use of precision seamless steel pipe manufacturing machinery structures or hydraulic equipment, etc., can greatly reduce the mechanical processing time, improve the material utilization, and help improve product quality.
[15] Stainless steel seamless pipe for structural use (GB/T14975-2002) is a hot-rolled stainless steel made of stainless steel that is widely used in the chemical industry, petroleum, textile, medical, food, machinery and other industrial corrosion-resistant pipes and structural parts and components. (Squeeze, expand) and cold drawn (rolled) seamless steel tubes.
[16] Stainless steel seamless pipe for fluid transportation (GB/T14976-2002) is a hot rolled (extruded, expanded) and cold drawn (rolled) seamless steel pipe made of stainless steel for conveying fluids.
[17] Shaped seamless steel tubes are a general term for seamless steel tubes of other cross-sectional shapes other than round tubes. According to the different shapes and sizes of steel pipe sections, they can be divided into equal-wall thickness special-shaped seamless steel pipes (code D), unequal wall thickness profiled seamless steel pipes (codenamed BD) and variable-diameter special-shaped seamless steel pipes (coded as BJ). Shaped seamless steel tubes are widely used in various structural parts, tools and mechanical parts. Compared with round tubes, shaped tubes generally have larger moments of inertia and section modulus, and have greater resistance to bending and torsion, which can greatly reduce the structural weight and save steel.
[18] Seamless steel tubes for low temperature pipelines (GB/T18984-2003) are applicable to the seamless steel tubes for low temperature pressure vessel pipes and low temperature heat exchanger pipes of -45°C to -195°C class.
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