Seamless steel pipes are categorized into thick-walled and thin-walled types depending on their application. They have a wide range of uses.
1. General-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel, or alloy structural steel, depending on their material. For example, seamless pipes made from low-carbon steels such as No. 10 and No. 20 are mainly used as pipelines for transporting steam, coal gas, liquefied gas, natural gas, various petroleum products, and other gases or liquids; seamless pipes made from medium-carbon steels such as 45 and 40Cr are mainly used to manufacture various machine parts and pipe fittings.
2. General-purpose seamless steel pipes are also supplied according to chemical composition and mechanical properties, or according to hydrostatic testing. Seamless steel pipes subjected to fluid pressure must pass the hydrostatic test.
3. Special-purpose seamless pipes are used in boilers, geological exploration, bearings, acid resistance, etc. Examples include oil and gas drilling pipes, cracking pipes for petrochemicals, boiler tubes, bearing tubes, and high-precision structural steel pipes for automobiles, tractors, and aviation.
1) Seamless steel pipes for structural use, mainly used in general structures and mechanical structures. Representative materials (grades): carbon steel 20 and 45; alloy steel Q345, 20Cr, 40Cr, 20CrMo, 30-35CrMo, 42CrMo, etc.
2) Seamless steel pipes for fluid transportation, mainly used in engineering and large equipment for fluid transportation pipelines. Representative materials (grades) are 20 and Q345, etc.
3) Seamless steel pipes for low and medium pressure boilers, mainly used in industrial and domestic boilers for transporting low and medium pressure fluids. Representative materials are 10 and 20 steel.
4) Seamless steel pipes for high pressure boilers, mainly used in high-temperature and high-pressure fluid transportation headers and pipelines in power plants and nuclear power plant boilers. Representative materials are 20G, 12Cr1MoVG, 15CrMoG, etc.
5) Seamless carbon steel and carbon manganese steel pipes for shipbuilding, mainly used in Class I and II pressure-resistant pipes for ship boilers and superheaters, etc. Representative materials include steel grades 360, 410, and 460.
6) Seamless steel pipes for high-pressure fertilizer equipment, mainly used for transporting high-temperature and high-pressure fluids in fertilizer equipment. Representative materials include 20, 16Mn, 12CrMo, and 12Cr2Mo.
7) Seamless steel pipes for petroleum cracking, mainly used in boilers, heat exchangers, and fluid transport pipelines in petroleum refineries. Representative materials include 20, 12CrMo, 1Cr5Mo, and 1Cr19Ni11Nb.
8) Seamless steel pipes for gas cylinders, mainly used for manufacturing various gas and hydraulic cylinders. Representative materials include 37Mn, 34Mn2V, and 35CrMo.
9) Hot-rolled seamless steel pipes for hydraulic supports, mainly used for manufacturing hydraulic supports, cylinders, and columns in coal mines, as well as other hydraulic cylinders and columns. Representative materials include 20, 45, and 27SiMn.
10) High-pressure seamless steel pipes for diesel engines, mainly used for high-pressure fuel lines in diesel engine injection systems. These pipes are generally cold-drawn, with 20A steel as a representative material.
11) Cold-drawn or cold-rolled precision seamless steel pipes, mainly used in mechanical structures and pressure equipment, requiring high dimensional accuracy and a smooth surface finish. Representative materials include 20 and 45 steel.
12) Cold-drawn seamless steel pipes and shaped steel pipes, mainly used for manufacturing various structural components and parts. These are made of high-quality carbon structural steel and low-alloy structural steel.
13) Precision inner diameter seamless steel pipes for hydraulic and pneumatic cylinders, mainly used for manufacturing cold-drawn or cold-rolled seamless steel pipes with precise inner diameter dimensions for hydraulic and pneumatic cylinders. Representative materials include 20 and 45 steel.
14) Stainless steel seamless pipes for boilers and heat exchangers, mainly used in boilers, superheaters, heat exchangers, condensers, catalytic converters, etc., in chemical plants. These are high-temperature, high-pressure, and corrosion-resistant steel pipes. Representative materials include 0Cr18Ni9, 1Cr18Ni9Ti, and 0Cr18Ni12Mo2Ti.
15) Structural stainless steel seamless pipes. Mainly used for general structures (hotel and restaurant decoration) and mechanical structures in chemical enterprises, these pipes are resistant to atmospheric and acid corrosion and possess a certain strength. Representative materials include 0-3Cr13, 0Cr18Ni9, 1Cr18Ni9Ti, and 0Cr18Ni12Mo2Ti.
16) Fluid transport stainless steel seamless pipes, mainly used for pipelines transporting corrosive media. Representative materials include 0Cr13, 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr17Ni12Mo2, and 0Cr18Ni12Mo2Ti.
17) Seamless steel pipes for automobile axle sleeves, mainly used for manufacturing high-quality carbon structural steel and alloy structural steel hot-rolled seamless steel pipes for automobile axle sleeves and drive axle housings. Its representative materials include 45, 45Mn2, 40Cr, and 20CrNi3A.
Post time: Apr-23-2026