Characteristics of cold drawn precision steel tubes
1. the outer diameter is smaller. 2. high precision small batch 3. high precision cold drawn finished the surface. 4. pipe cross area is more complicated. 5. steel tube superior metal keys. 1, manufacture method According to different production methods can be divided into hot-rolled pipes, cold rolling mill, cold drawn tubes, extruded tubes, etc. 1.1, hot rolled seamless tubes in automatic rolling unit production. Surface defect of billets on the check for, and remove solid pipe, cut into desired lengths, centering on a perforated tube end to end, and then sent to the furnace heated, perforated at the punch. Perforated while continuing to rotate and move forward, under the rollers and head, it tube gradually formed inside the cavity, called the capillary. Then continue on to automatic rolling machine rolling. Finally the whole entire wall thickness, warp sizing machine sizing, meet the specification requirements. Production hot-rolled seamless steel tube continuous rolling is an advanced method. 1.2, if you desire to get the smaller size and better quality of seamless tubes, cold rolling, cold-drawing must be used or a combination of methods. Cold rolling is usually conducted on a two-high rolling mill, and pipe tapered circular Groove of cone-shaped head is not moving up the loop-hole in the roll. Cold-drawn usually in 0.5~100T-single or double chain of cold-drawing machine. 1.3, extrusion, tube to be heated in a closed extruded cylinder, perforated Rod movement together with the extruded rod, extruded parts extruded from a smaller die. This method can produce a smaller diameter pipe. 2, use 2.1, seamless pipe use is very extensive. General purpose seamless tube made of ordinary carbon structural steel, low-alloy structural steel or alloy structural steel rolling production, mainly as a transmission fluid pipe or structural parts. 2.2, according to use three supply: supply, according to the chemical composition and mechanical properties of a; b, according to the mechanical properties of supply; c, supplied by the hydraulic test. Steel tubes supplied by class a, b, such as a liquid under pressure, and water test. 2.3, special-purpose seamless tube boiler seamless steel pipe, seamless pipe and seamless pipe for oil and other geological variety. 3, type 3.1, according to different production methods can be divided into hot-rolled seamless steel pipe pipe, cold rolling mill, cold drawn tubes, extruded tubes, etc. 3.2, classified by shape round tube, profiled tubes Division. Profile tubes except for square and rectangular tubes, and oval tube, half pipe, pipe triangular, hexagonal tubes, plum-shaped, convex-shaped tube tube. 3.3, according to the different material, divided into ordinary carbon structural tubes and low alloy structural tubing, high quality carbon structural tube, alloy tube, stainless steel pipe, etc.
3.4, according to specific purposes, boiler tubes, geological pipe, oil pipe, and so on. 4, size and appearance quality Seamless pipes provided by GB/T8162-87 4.1, size: hot rolled tube outer diameter 32~630mm. 2.5~75mm wall thickness. Cold rolled (cold drawn) outer diameter 5~200mm. 2.5~12mm wall thickness. 4.2 appearance quality: tube, fold, roll fold inside and outside surface must not have cracks, delamination, hairline and scarring defects exist. These shortcomings should be completely removed, cleared no thickness and outside diameter than negative deviation. 4.3, the ends of the pipe should be cut at right angles, and remove burrs. Wall thickness of pipe allows gas cutting and hot saws are greater than 20mm. Supply and demand also agreed not to cut head. 4.4, cold-drawn or cold-rolled precision seamless steel tube of the surface quality of the reference GB3639-83. 5 chemical composition test 5.1, according to the chemical composition and mechanical properties of the supply of domestically produced seamless tubes, such as 10, 15, 20, 25, 30, 35, 40, 45 and 50th steel chemical composition should comply with the provisions of GB/T699-88. Import standard inspection of seamless steel tube as specified in the contract. 09MnV, 16Mn, 15mnv steel chemical composition should comply with the provisions of GB1591-79. 5.2, specific analytical methods according to GB223-84 of the steel and alloy chemical analysis method of the part of the building. 5.3 deviation reference GB222-84, analysis of the chemical composition of chemical analysis of steel samples and finished product tolerances. 6, physical performance test
6.1, according to mechanical properties of supply of domestic seamless steel tube, steel plain carbon steel by GB/T700-88 CPI (but must ensure that the sulphur content of no more than 0.05% and phosphorus content less than 0.045%), the mechanical properties should conform to the values set out in the GB8162-87 table. 6.2, supplied by water pressure test of domestic seamless steel tube standard hydrostatic testing must be guaranteed. 6.3, imports of seamless physical performance test carried out according to relevant standard stipulated in the contract. 7, the main imports and exports of 7.1, seamless pipe and tube imports a lot. The main importing countries are Germany and Japan. European countries such as Romania, and Russia, and Switzerland, and France, and Spain, Czechoslovakia, Yugoslavia, Hungary and other countries have imported. And a few from South America, Argentina, and Mexico and other countries importing. 7.2, in accordance with the different requirements of our unit, imports of seamless pipe sizes up to more than 100 species of common specifications are 15922mm, 1595mm, 15918mm. 114.38mm、114.310mm、114.313mm。 Length ranges usually 5~8M or 4~7m. Mostly hot-rolled carbon and ST65. Import specifications diameter smallest to 305mm, the biggest 47813mm. 7.3, from France and Spain had imported a small amount of smaller diameter thin-walled seamless pipe, such as 183mm,223mm, 26.93mm etc. Implementation of Germany between Mannesmann Demag steel plant of general rules.
7.4, from Hungary and Japan imports of seamless pipes, often references DIN2448, DIN1629. 7.5, the claims of imports, imports of seamless quality problems existed are: chemical failed, flattening test for splitting tensile strength is low, such as severe corrosion and pits. Source: http://www.steel-tubes.com/
