Welded rectangular pipe is made of strip steel as raw material and manufactured at room temperature. Welded square pipe can be divided into straight welded pipe, large caliber square pipe and spiral welded pipe. Due to the different uses of welded pipe, the standards of welded pipe in different countries are summarized in turn.
First, galvanized welded square pipes for low pressure fluid transportation, standard No. GB/T3091-2008. Represents material Q235A, Q235BQ345B, etc. It is mainly used for conveying water, gas, air, oil and heating hot water or steam. Its use is limited to generally low pressure fluids.
Second, galvanized welded square pipe for low-pressure fluid transportation, standard number GB/ t3092-2008.Represents material. Same as above.Mainly used for conveying water, gas, air, oil and heating hot water or steam and other general lower pressure fluid, square pipe appearance using hot galvanized or cold galvanized anticorrosive process.
Third, mine fluid transport welded square pipe, standard no:I GB/ t14291-2000.Q235A, B grade steel, mainly used for straight seam welding square pipe for mine pressure wind, drainage and shaft gas discharge.
Fourth, large diameter welded square pipe for low-pressure fluid transportation, standard number is GB/ t14980-1994.Represents material Q235AB level.Mainly used to transport water, sewage, gas, air, heating steam and other low-pressure fluid.
Fifth, welded stainless steel square pipe for mechanical structure, standard number is GB/ t12770-1991.Representative materials: 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.Mainly used for machinery, automobile, bicycle, furniture, hotel and restaurant decoration and other mechanical parts and structures.
Sixth, welded stainless steel square pipe for fluid transportation, standard no. GB/ t12771-1991.The representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.Mainly used for conveying low pressure corrosive medium.
Seventh, spiral square pipe for low-pressure transmission (standard of ministry of petroleum), standard number SY/ t5037-2008.Representative material is carbon steel material such as Q235BQ345B.Mainly used for low-pressure water, oil, natural gas, heating and other pipelines.
Eighth, the square pipe for conveying combustible and non-combustible fluids, standard number is GB/T9711.1(GB/T9711.2)-1997. The representative material is l245-l415, and other pipeline steel.Mainly used to transport inflammable and non-inflammable fluid low pressure or high pressure with square pipe, the requirements are relatively high.