1. manufacturing methods
According to the different production methods can be divided into hot-rolled Line Pipe, cold-rolled Line Pipe, cold-drawn Line Pipe, extrusion pipe.
1.1, hot-rolled seamless pipe is generally produced in the automatic rolling mill unit. The solid Line Pipe is inspected and cleared of surface defects, cut into the required length, centered on the end face of the perforation of the Line Pipe, and then sent to the heating furnace for perforation. In the perforation at the same time continue to rotate and forward, in the roll and the role of the head, the Line Pipe gradually formed inside the cavity, said capillary. And then sent to the automatic rolling mill to continue rolling. Finally, the whole machine is the whole wall thickness, the sizing machine to achieve the specifications. The use of continuous rolling mill production of hot rolled Line Pipe is a more advanced method
1.2, if you want to get smaller and better quality seamless pipe, must use cold-rolled, cold drawn or a combination of the two methods. Cold rolling is usually carried out on a two-roll mill where the wire is rolled in a ring-shaped bore formed by a variable cross-section circular orifice and a stationary tapered head. The cold drawing is usually carried out on a single chain or double chain type drawing machine of 0.5 to 100T.
1.3, the extrusion method is about to heat a good Line Pipe placed in a closed extrusion cylinder, perforated rods and squeeze bar with the movement, so that extrusion from the smaller die hole extrusion. This method can produce smaller diameter Line Pipe.
2.1, seamless use of a Line Pipe. General use of seamless pipe by the ordinary carbon structural steel, low-alloy structural steel or alloy structural steel rolling, the largest output, mainly used for conveying fluid pipe or structural parts.
2.2, according to the use of different sub-three supply: a, according to chemical composition and mechanical properties of supply; b, according to the mechanical performance supply; c, according to the hydraulic test supply. According to a, b class supply of wire, such as for the use of liquid pressure, but also for water pressure test.
2.3, the special purpose of the seamless pipe with a seamless pipe, seamless use of geological and seamless use of oil and other seamless.
3.1, according to the different production methods can be divided into hot-rolled Line Pipe, cold-rolled Line Pipe, cold-drawn Line Pipe, extrusion pipe.
3.2, according to the shape of a round Line Pipe, shaped Line Pipe of the points. Shaped Line Pipe in addition to square Line Pipe and rectangular Line Pipe, there are elliptical Line Pipe, semi-circular Line Pipe, triangular Line Pipe, hexagonal Line Pipe, convex-shaped Line Pipe, plum-shaped Line Pipe.
3.3, according to the different materials, divided into ordinary carbon structural Line Pipe, low-alloy structure Line Pipe, high-quality carbon structural pipe, alloy structure Line Pipe, stainless steel and so on.
3.4, according to the special purpose points, a boiler Line Pipe, geological pipe, oil pipe and so on.
4. specifications and appearance quality
Seamless pipe according to GB / T8162-87 regulations
4.1, specifications: hot-rolled Line Pipe diameter 32 ~ 630mm. Wall thickness of 2.5 ~ 75mm. Cold rolled (cold drawn) pipe diameter 5 ~ 200mm. Wall thickness of 2.5 ~ 12mm.
4.2, the appearance of quality: the inner and outer surface of the Line Pipe shall not have cracks, folding, rolling off, from the layer, hair and scar defects exist. These defects should be completely removed, after removal of the wall thickness and diameter should not exceed the negative deviation.
4.3, both ends of the line should be cut at right angles, and remove the burr. Wall thickness greater than 20mm to allow gas cutting and hot saw cutting. The agreement between the supply and demand sides may not be cut.
4.4, cold drawn or cold rolled precision wire "surface quality" with reference to GB3639-83.
5. the main import and export situation
5.1, the general seamless import volume is very large. The main importing countries are Germany and Japan. European countries such as Romania, Russia, Switzerland, France, Spain, the Czech Republic, Yugoslavia, Hungary and other countries have imported. There is also a small amount of imports from South America, Argentina, Mexico and other countries.
5.2, according to the different requirements of China's cargo units, imports of seamless specifications up to 100 kinds of common specifications are 15922mm, 1595mm, 15918mm. 114.38 mm, 114.310 mm, 114.313 mm. The length is generally 5 ~ 8m or 4 ~ 7m range. Mainly hot-rolled carbon structure, steel number ST35.ST45 and ST65. Import specifications of the smallest diameter of 305mm, the largest 47813mm.