... steel, square tube, rectangular tube.Products: pipe: (GB/T8162-2008): (GB/T8163-2008), fluid tubes, in the low-pressure boiler tubes: (GB/T3087 ... -2008), high pressure boiler tube: (GB/T5310-2008), oil cracking ... tube: (GB/T5312-1999): (GB/T8162-2008), alloy tube, high pressure alloy pipe: (GB/T5310-2008) and a series of steel ...