A seamless pipe is a long strip of steel with a hollow section and no seams around it. According to different production methods, it can be divided into hot-rolled tubes, cold-rolled tubes, cold-drawn tubes, extruded tubes, etc. Generally used in fluid conveying pipes, boiler plants, engineering, mechanical processing plants.
Seamless steel pipe production process:
1. Hot rolling (extruded seamless steel pipe): round tube billet → heating → piercing → three-roll cross rolling, continuous rolling or extrusion → stripping → sizing (or reducing) → cooling → straightening → hydraulic test (or flaw detection) → marking → warehousing
2. Cold drawn (rolled) seamless steel pipe: round tube blank→heating→piercing→heading→annealing→pickling→oiling (copper plating)→multi-pass cold drawing (cold rolling)→blank tube→heat treatment→straightening→water Pressure test (flaw detection) → marking → storage.
After the quality inspection of steel pipes, strict manual selection is required. Then spray the serial number, specification, production batch number, etc. with paint. And hoisted into the warehouse by crane.
Hot-rolled seamless pipes are generally produced on automatic pipe rolling units. After checking and removing surface defects, the solid tube blank is cut into the required length, centered on the perforated end face of the tube blank, then sent to the heating furnace for heating, and pierced on the piercing machine. Spin and advance the solid blank inside the process of piercing holes under the influence with the roller as well as the end. Then the solid blank is hollow finally, which is called gross pipe. Send to the automatic pipe rolling machine to continue rolling. Finally, the wall thickness is adjusted by the equalizing machine, and the size is sized by the sizing machine to meet the specification requirements. It is a more advanced method to produce hot-rolled seamless steel pipes by using continuous rolling mills.
If you want to obtain seamless pipes with smaller size and better quality, you must use cold rolling, cold drawing or a combination of both. Cold rolling is usually carried out on a two-roll mill, and the steel pipe is rolled in an annular pass formed by a circular hole groove with variable cross-section and a stationary tapered plug. Cold drawing is usually carried out on a single-chain or double-chain cold drawing machine of 0.5-100T.
The extrusion method is to place the heated tube blank in a closed extrusion cylinder, and the perforated rod and the extrusion rod move together to make the extruded part extrude from the smaller die hole. This method can produce steel pipes with smaller diameters.
Classification and material of seamless steel pipe
Product Name | Material | Executive Standard | Spot Specifications | Application |
Alloy tube | 12Cr1MoVG 12CrMoG 15CrMoG
12Cr2MoCr5MoCr9Mo10Cr 9Mo1VNb15NiCuMoNb5 | 12Cr1MoVG 12CrMoG 15CrMoG
12Cr2MoCr5MoCr9Mo10Cr9Mo 1VNb15NiCuMoNb5 | ∮8-1240*1-200 | It is suitable for seamless steel pipes for high temperature resistance, low temperature resistance and corrosion resistance in petroleum, chemical industry, electric power and boiler industries. |
stainless steel pipe | 0Cr18Ni9<304> 00Cr19Ni10<304L> 00Cr25Ni20<310S> 0Cr17Ni12Mo2<316> 00Cr17Ni14Mo2<316L> 1Cr18Ni9Ti<321> 0Cr18Ni10Ti 0Cr18Ni11Nb<347> | GB/T14975-2002 GB/T14976-2002 GB13296-2007 ASTM A213 ASTM A269 ASTM A312 JIS G3459 DIN 17458 | ∮6-630*0.5-60 | It is suitable for petroleum, aviation, smelting, food, water conservancy, electric power, chemical industry, chemical, chemical fiber, medical machinery and other industries. |
Cryogenic tube | 16MnDG、10MnDG、09DG 09Mn2VDG、06Ni3MoDG ASTM A333Grade1 ASTM A333Grade3 ASTM A333Grade4 ASTM A333Grade6 ASTM A333Grade7 ASTM A333Grade8 ASTM A333Grade9 ASTM A333Grade10 ASTM A333Grade11 | GB/T18984-2003 ASTM A333 | ∮8-1240*1-200 | Suitable for -45℃~-195℃ low-temperature pressure vessel pipes and seamless steel pipes for low-temperature heat exchanger pipes. |
High pressure boiler tube | 20G ASTM SA106B/C ASTM SA210A/C ST45.8-III | GB5310-1995 ASTM SA106 ASTM SA210 DIN17175-79 | ∮8-1240*1-200 | Suitable for manufacturing high-pressure boiler heating pipes, headers, steam pipes, etc. |
High pressure fertilizer pipe | 10 20 16Mn | GB6479-2000 | ∮8-1240*1-200 | Suitable for chemical equipment and pipelines with a working temperature of -40--400°C and a working pressure of 10-32Mpa |
Petroleum cracking tube | 10 20 | GB9948-2006 | ∮8-630*1-60 | Furnace tubes, heat exchanger tubes and pipes for petroleum refineries. |
Low and medium pressure boiler tube | 10# 20# 16Mn | GB3087-2008 | ∮8-1240*1-200 | Suitable for manufacturing low-pressure and medium-pressure boilers and locomotive boilers of various structures. |
Fluid delivery tube | 10#、20# ASTM A106A,B,C、A53A,B 16Mn | GB/T8163-2008 ASTM A106 ASTM A53 | ∮8-1240*1-200 | General seamless steel pipes suitable for conveying fluids. |
General structural pipe | 10#、20#、45#、27SiMn ASTM A53A,B 16Mn | GB/T8162-2008 GB/T17396-1998 ASTM A53 | ∮8-1240*1-200 | Suitable for general structures, engineering supports, machining, etc. |
Oil Casing | J55、K55、N80、L80 C90、C95、P110 | API SPEC 5CT ISO11960 | ∮60.23-508.00 *4.24-16.13 | Tubing is used to extract oil or natural gas in oil wells, and casing is used as the well wall of oil and gas wells. |
Line pipe | A、B、X42、X46、X52、X56、X60、X65、X70、X80 L245、L290、L360、L415、L450 | API SPEC 5L GB/T9711.1 GB/T9711.2 | ∮32-1240*3-100 | Oxygen, water and oil delivery pipes used in oil and gas industry. |
straight seam steel pipe | 20、Q195、Q215A,B Q235A,B、Q345A,B,C,D,E | GB/T13793-1992 GB3091-2001 | ∮32-630*1-30 | Suitable for general structural support, low-pressure fluid delivery, etc. |
Spiral steel pipe | Q235A-B、Q345A-E | SY/T5037-2000 | 219-2820*4-20 | Suitable for steel pipes for low-pressure fluid transmission. |