Seamless steel tube is a hollow cross-section, no seams around a circular, square, rectangular steel. Seamless steel ingot is made of perforated or solid through the capillary tube, and then hot-rolled, cold-rolled or cold call is made. Seamless steel tube having a hollow cross-section, a large number of channels for transporting fluids, such as pipes, pipe and solid steel bar, compared to the same torsional strength in bending, lighter, is an economic cross-section steel, widely used in the manufacture of structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle frames and construction using steel scaffolding.
First, the development status of seamless steel tube
US Department of Commerce February 24, 2010 announced the preliminary determination, to impose seamless steel tube imports from China from 11.06 to 12.97 percent countervailing duties ranging. US Department of Commerce said in a statement that from 2006 to 2008, the United States increased by 131.52% from Chinese imports of seamless steel tubes, amount to approximately $ 382 million.
Last October, the US Department of Commerce should the United States Steel Corporation, V & M Star Company, TMK IPSCO companies and the United
Requirements, the countervailing case filing. At that time, Chinese Ministry of Commerce officials have said that blindly accused imports from China of dumping or subsidies, the lack of factual basis, China is firmly opposed.
In early November last year, the US International Trade Commission has made this preliminary determination. Currently calendar display, the US Commerce Department will make a final ruling in May this year, the US International Trade Commission will make a final ruling in June.
By the financial crisis and economic downturn, the United States since 2009, frequent use of trade remedy measures.
International Trade World Bank senior economist Richard • Brown to Xinhua News Agency reporters Ti Gong and De Yifen latest research report shows that in 2009, the global implementation of the countervailing and anti-dumping, safeguard and other trade restrictions on the number of policies increased compared to 2008 29.5%. Trade protectionism has become an important risk affecting the world economic recovery.
The Profiles of Seamless Steel
Seamless Steel Tube wall thickness mm diameter * number indicates. Hot-rolled and cold rolled seamless steel tube points (written) seamless steel categories. Hot-rolled seamless steel tube sub-normal, low, medium pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel tube, oil cracking pipe, geological steel tube and other steel tube. Cold-rolled (allocated) Subject to sub-general seamless steel pipe, low pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, the other steel, but also includes carbon thin-walled steel, alloy thin-walled steel pipe, walled stainless steel, special steel pipe. Hot-rolled seamless pipe diameter is generally greater than 32mm, wall thickness 2.5-75mm, cold-rolled seamless steel pipe diameter can go to 6mm, wall thickness can be 0.25mm, thin-walled tube diameter to 5mm wall thickness of less than 0.25mm, cold high dimensional accuracy than hot-rolled.
Seamless is 10,20,30,35,45 and other high quality carbon steel 16Mn, 5MnV low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2,40MnB and other structural steel hot-rolled or cold-rolled steel. 10,20 and other low-carbon steel seamless pipe is mainly used for fluid pipes.Seamless 45,40Cr etc. made of carbon steel used to manufacture mechanical parts, such as cars, tractors and the force components. General seamless steel pipes to ensure the strength and flattening test. Hot-rolled steel hot-rolled state or heat treatment delivery; cold to heat treatment delivery.
Second, the implementation of the standard of seamless steel tube
1, structure seamless pipe (GB / T8162-2008) seamless steel pipe for general structure and mechanical structure.
2, transmission fluid with seamless steel tube (GB / T8163-2008) is generally seamless steeltube used for conveying water, oil, gas and other fluids.
3, low and medium pressure boiler seamless tube (GB3087-2008) is used in the manufacture of various structural low and medium pressure boiler superheated steam pipes, boiling water pipe and locomotive boiler quality carbon structural steel hot superheated steam pipe and brick arch effective rolled and cold drawn (rolled) seamless steel tube.
4, high-pressure boiler seamless pipe (GB5310-2008) is used to manufacture high-quality carbon steel and more pressure water tube boiler heating surface with steel, alloy steel and heat-resistant stainless steel seamless.
5 fertilizer equipment with high pressure seamless steel tube (GB6479-2000) is applied to the working temperature of -40 ~ 400 ℃, working pressure of high-quality carbon structural steel and alloy steel 10 ~ 30Ma of chemical equipment and pipe seamless steel tubes.
6, petroleum cracking seamless pipe (GB9948-2006) is applied to the oil refinery furnace tubes, heat exchangers and pipe seamless steel tube.
7. Geological Drilling Pipe (YB235-70) is available for the geological department of the steel core drilling, use can be divided into the drill pipe, drill collars, core pipe, casing and precipitation tubes.
8 diamond core drilling seamless pipe (GB3423-82) for diamond core drilling drill, core rods, seamless steel tube casing.
9, oil drilling pipe (YB528-65) is used for oil drilling at both ends of thickening or external upset seamless steel tubes. Steel sub-threading and not two, Threading Pipe Fittings links, no threading methods and tools useful butt joint connection.
10. Ship carbon steel seamless pipe (GB5213-85) is the manufacture of ship Class I pressure piping, Ⅱ grade pressure piping, boiler and Superheater carbon steel seamless tube. Carbon steel seamless pipe wall temperature does not exceed 450 ℃, alloy steel seamless pipe wall temperature exceeds 450 ℃.
11 automobile axle casing seamless steel tube (GB3088-82) manufacturing automobile axle casing and the drive axle axle shaft tubes of high-quality carbon structural steel and alloy structural steel hot-rolled seamless steel tubes.
12 diesel engine with high-pressure tubing (GB3093-2002) is to create high-pressure diesel injection systems of cold drawn seamless tubes.
13 hydraulic and pneumatic cylinder with precision internal diameter seamless steel pipe (GB8713-88) is the manufacture of hydraulic and pneumatic cylinder with a cold drawn or cold rolled precision seamless steel tubes with precision diameter size.
14, cold drawn or cold rolled precision seamless steel tube (GB3639-2000) is used for high dimensional accuracy mechanical structure, hydraulic equipment and good surface finish cold drawn or cold rolled precision seamless steel tubes. Use a precision seamless steel pipe manufacturing mechanical structure or hydraulic equipment, can greatly reduce machining time, improve material utilization, and help to improve product quality.
15, the structure of stainless steel seamless tube (GB / T14975-2002) is widely used for hot rolling corrosion-resistant pipes and structural parts and components of stainless steel chemical, petroleum, textile, medical, food, machinery and other industrial made ( extrusion, expansion) and cold drawn (rolled) seamless steel pipe.
16 fluid transport stainless steel seamless tube (GB / T14976-2002) is a hot-rolled for the transmission fluid made of stainless steel (extrusion, expansion) and cold drawn (rolled) seamless steel pipe.
17. Shaped seamless steel tube is in addition to other general term seamless pipe cross-sectional shape. Press the pipe cross-section can be divided into different shapes and sizes and so shaped seamless steel pipe wall thickness (code D), ranging shaped seamless steel pipe wall thickness (code-named BD), variable diameter shaped seamless steel pipe (code-named BJ).Shaped seamless steel tubes are widely used in various structural parts, tools and machinery parts. And the tube compared tubes generally have a greater moment of inertia and section modulus, flexural torsional greater capacity, can greatly reduce the structural weight, saving steel.
18. The cryogenic tube seamless steel pipe (GB / T18984-2003) suitable for -45 ℃ ~ -195 ℃ temperature pressure vessels level and low temperature heat exchanger pipe seamless steeltube