Steel is generally not used in the manufacture of steel pipe
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High quality carbon structural steel (GB/T699-1999) in addition to contain C element in steel, a certain amount of Si element for Flange wood screws Manufacturers deoxidation (generally no more than 0.40%), and Mn (generally no more than 0.80%, up to 1.20%) alloy elements, excluding other alloying elements (except for residual element). This kind of steel must ensure the chemical composition and mechanical properties at the same time. Its S and P content of impurity elements in general are controlled under 0.035%. If controlled under 0.030% called high quality steel, its brand behind should add an "A", such as 20 A; If P is controlled under 0.025%, S controlled below 0.020%, called special high-quality steel, the brand should be added behind the "E" in order to show the difference.For the other residual alloying elements taken by the raw materials into the steel, such as Cr, Ni, Cu and so on, the content of general controlled: Cr≤0.25%Ni≤0.30%Cu≤0.25%. Some brands of Mn content is up to 1.40%, known as Mn steel.This kind of steel relied on adjusting the amount of carbon
to improve the mechanical properties of steel, therefore, according to the carbon content, this kind of steel can be divided into: low carbon steel, carbon content, generally less than 0.25%, such as 10, 20 steel, etc.Medium carbon steel, carbon content is in commonly between 0.25 ~ 0.60%, 35, 45 steel, etc.;High carbon steel, carbon content is generally greater than 0.60%.This kind of steel is generally not used in the manufacture of steel pipe.Actually, there are no obvious boundary of the carbon content.Such steel production is bigger, with broad application, rolling (forging) more commonly made into round, square, flat profiles, such as plate and seamless steel pipe. Mainly used in the manufacture of general structure and the mechanical structure parts, components and building structure and pipe conveying fluid.Seamless steel pipe production methods is broadly divided into cross rolling and extrusion method. Former method is to use oblique roll bad perforated tube, and then rolling it extends. This method of production speed, but higher on the tube workability requirements, mainly for the production of carbon steel and low alloy steel pipes. After the rule is puncher billet or ingot will be perforated, and then into a pipe extruder, this method is lower than the efficiency of cross rolling method is suitable for the production of high-strength steel pipe. Cross rolling method and extrusion billet or ingot must first heating, production of hot-rolled steel tube called. Produced by thermal processing of the cold pipe may sometimes be needed then. Cold working in two ways: one is the method of drawing, the pipe is drawn through a die to extubation, the steel pipe is tapered, elongated; Another method is to cold rolling, it is the brother of the invention Mengneisiman The cold rolling mill used in the method. A seamless steel tube cold working of steel can be improved dimensional accuracy and finish machining, and the like to improve the mechanical properties of the material. Hot-rolled and cold drawn thermal processing is cold. The main difference: in the hot rolling temperature above the recrystallization rolling, cold rolling at a temperature below the recrystallization rolling cold rolling and sometimes there will be heated, but the temperature is relatively low, as it will produce cold rolled after processing. hardening, if required for the molding material is relatively high, but also for annealing of cold-rolled and hot-rolled plates or profiles generally, and wire drawing is generally cylindrical cross-section. Another hot-rolled sheet is generally higher alloy content, high strength steel, and cold-rolled carbon steel is a low alloy by cold rolling can improve strength, ensure the surface quality of the material.
Cold drawn seamless steel pipe and hot-rolled seamless steel tubes of different distinction and plate. Seamless steel pipe manufacturing process is different because it is divided into hot-rolled (extrusion) Seamless two seamless and cold drawn (rolled). Cold drawn (rolled) pipe is divided into two circular pipe and shaped tube: cold drawn steel tubes generally require multiple drawing between each drawing must be appropriate to stress annealing, to ensure a smooth next drawing proceed. From the appearance of cold-rolled seamless steel tubes tend to be small-diameter, hot-rolled seamless steel tubes tend to be large diameter. Accuracy than hot-rolled seamless steel cold-rolled seamless steel pipe, hot-rolled seamless steel pipe price is also higher than. Generally smaller diameter cold drawn seamless tubes, mostly in 108mm or less, especially precision cold drawn seamless pipe diameter is very high, cold drawn seamless pipe lengths are generally shorter than hot-rolled seamless pipe. Cold drawn seamless Wood Screws Manufacturers pipe wall thickness aspect than hot-rolled seamless uniform.