Low and medium pressure boiler tubes are made of ingots or solid billets that are perforated to form a burr tube, and then hot rolled, cold rolled or cold dialed. Seamless steel pipe has an important position in China's steel pipe industry. According to incomplete statistics, China's existing seamless pipe production enterprises about 240 more than, seamless steel pipe unit about 250 sets, the annual production capacity of about more than 4.5 million tons. From the caliber point of view, <φ76, accounting for 35%, <φ159-650, accounting for 25%. In terms of varieties, 1.9 million tons of general-purpose tubes, accounting for 54%; 760,000 tons of petroleum tubes, accounting for 5.7%; 150,000 tons of hydraulic pillars, precision tubes, accounting for 4.3%; stainless tubes, bearing tubes, automotive tubes a total of 50,000 tons, accounting for 1.4%.
Low and medium pressure boiler tube mechanical properties: tensile strength σb (MPa): ≥ 410 (42) yield strength σs (MPa): ≥ 245 (25) elongation δ5 (%): ≥ 25 section shrinkage ψ (%): ≥ 5, hardness: not heat treatment, ≤ 156HB, sample size: sample size 25mm heat treatment specifications and metallographic organization: heat treatment specifications: normalized, 910 ℃, Air cooling. Metallographic organization: ferrite + pearlite.
Medium and low pressure boiler tube execution standard: GB3087-1999 seamless steel tube for low and medium pressure boiler.
Medium and low pressure boiler tubes are hot rolled and cold drawn (rolled) seamless tubes of high quality carbon structural steel used for making superheated steam tubes, rolled water tubes and superheated steam tubes for locomotive boilers, large smoke tubes, small smoke tubes and arch brick tubes for various structures of low and medium pressure boilers. Mainly used for industrial boilers and living boilers to transport low and medium pressure fluid pipes. The representative material is 10 and 20 gauge steel.
