High quality seamless steel tube is made of solid tube blank after perforation.

Production method of high quality seamless pipe

According to the production methods can be divided into hot tube, cold drawn tube, pipe, pipe extrusion etc..

Production of hot rolled seamless pipe in general on the automatic pipe rolling mill. Solid tube blank check and clear the surface defects, cut into required length, in the tube hole end surface of centering, then sent to a heating furnace, in punch. In perforated while continuing to rotate and advance, in the roll and immediate action, tube gradually form a cavity, called capillary. Sent to the automatic tube rolling mill on rolling. Finally, the whole wall thickness of the whole machine is fixed, and the size of the sizing machine is determined. The production of hot rolled seamless steel tube by continuous rolling mill is a more advanced method.

In order to obtain smaller size and better quality of seamless tube, cold rolling, cold drawing method must be used or combined. Cold usually in two roller mill, rolling ring groove tapered plug pipe in variable cross section circular slot and the composition of the. Cold drawing was usually in the 0.5 ~ 100T single chain or double chain drawbench.

The extrusion method is placed in a closed extrusion cylinder, and the punched rod and the extrusion rod move together, so that the extruding part is extruded from the smaller die hole. This method can produce smaller diameter steel tube.

High quality seamless tube use

High quality seamless pipe for a wide range of uses. Seamless pipes are used for general carbon structural steel, low alloy structural steel or alloy steel rolling, the most output, mainly used for conveying fluid pipe or structural parts.

According to the different purposes of three types of supply: A, according to the chemical composition and mechanical properties of supply; B, according to the mechanical properties of supply; C, according to the water pressure test supply. According to the B, a class supply of steel pipe, such as used to bear the pressure of liquid, but also to carry out the hydrostatic test.

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type

High quality seamless pipe production methods can be divided into hot tube, cold rolling, cold drawing tube, pipe extrusion etc..

According to the classification of the shape of circular pipe, special-shaped pipe. In addition to the square shaped tube and rectangular tubes, and oval tube, tube, pipe, tube, hexagonal, triangular convex shaped tube, plum shaped tube.

According to the different materials, is divided into ordinary carbon structure, low alloy structure, quality carbon structure, alloy pipe, stainless steel pipe, etc..

According to the special purpose, there are boiler tube, geological pipe, oil pipe, etc..

Quality seamless pipe specifications and appearance quality

Seamless pipe according to the provisions of GB/T8162-87

Specification: hot rolled tube outside diameter 32 ~ 630mm. Wall thickness 2.5 ~ 75mm. Cold rolled (Leng Ba) outside diameter of 5 ~ 200mm. Wall thickness 2.5 ~ 12mm.

Exterior quality: steel surface shall not have cracks, folding, rolling reduction, separation, hairline and scarring and defects. These defects shall be completely removed, and the wall thickness and outer diameter shall not exceed the negative deviation.

Both ends of the steel pipe should be cut at right angles, and remove the burr. Steel tube wall thickness greater than 20mm allows cutting and thermal cutting. The agreement between the two sides can not cut off the supply and demand.

Cold drawn or cold-rolled precision seamless steel tube "surface quality" by GB3639-83.

Test of chemical composition of high quality seamless pipe

Seamless pipes, such as 10, 15, 20, 25,, 30, 35, 40,, 45,,, and 50 steel shall be in accordance with the provisions of the GB/T699-88. Inspection of imported seamless pipe in accordance with the relevant standards stipulated in the contract. The chemical composition of 09MnV, 16Mn and 15MnV steel shall conform to the provisions of GB1591-79.

Specific analysis methods refer to the relevant parts of GB223-84 "steel and alloy chemical analysis method".

Analysis of deviation with reference to GB222-84 "steel for chemical analysis of samples and finished product chemical composition allowable deviation".

Physical property test of high quality seamless tube

According to the domestic seamless performance of supply mechanism, plain carbon steel GB/T700-88 produced by a (but must ensure that the sulfur content of less than 0.050% and the phosphorus content of not more than 0.045%), the mechanical properties should be consistent with the numerical table stipulated in GB8162-87.

Domestic seamless pipes supplied by hydraulic test shall be guaranteed by the standard.

The physical performance test of the seamless pipe is carried out according to the relevant standards stipulated in the contract.

Quality seamless pipe main import and export situation

General seamless pipe imports a lot of. Major importing countries are Germany and japan. European countries such as Romania, Russia, Switzerland, France, Spain, Czech, Yugoslavia, Hungary and other countries have imported. There are a small amount of imports from Argentina, Mexico and other countries from South america.

According to the different requirements of China's cargo units, imported seamless pipe specifications as many as 100 kinds of common specifications are 1595mm, 15922mm, 15918mm. 114.38mm, 114.310mm, 114.313mm. The length is generally 5 ~ 8m or 4 ~ 7m. Is the main structure of hot rolled carbon steel to ST35.ST45 and ST65. The smallest diameter of the import specifications for the 305mm, the largest 47813mm.

From France and Spain have imported a small amount of small diameter and thin wall seamless tubes, such as 223mm, 183mm, 26.93mm, etc.. Implementation of the general rules mannasiman steel pipe in germany.

Seamless pipe from Hungary and Japan, often with reference to DIN2448, DIN1629.

In the import claim case, quality problems of imported seamless tubes are: unqualified chemical compositions and flattening test split, low tensile strength, serious corrosion and concave