English straight steel pipe (Straightsteel pipe), general welded pipe: General welded pipe is used to transport low-pressure fluid. Manufactured from Q195, Q21, Q23 steel, and Q235B carbon. High frequency welding is also available
High-frequency welding is based on the principle of electromagnetic induction and the skin effect, proximity effect, and eddy current effect of AC charges in the conductor, which locally heats the steel at the edge of the weld to a molten state, and extrudes the roller to make the butt weld crystallize. To achieve the purpose of welding. High frequency welding is an induction welding (or pressure contact welding). It does not require welding filler, no welding spatter, narrow welding heat affected zone, beautiful welding molding, good welding mechanical properties, etc., so it is affected by the production of steel pipes. Wide application.
The high-frequency welding of steel tubes uses the skin effect and proximity effect of alternating current. After rolling (steel), a steel tube is formed into a round tube with a broken cross-section, which is rotated in the tube near the center of the induction coil. Or a set of resistors (magnetic rods). The resistors form an electromagnetic induction loop with the tube blank opening. Under the skin effect and proximity effect, the edge of the tube blank opening generates a strong and concentrated thermal effect, which makes the edge of the weld After quickly heating to the temperature required for welding and pressing by the pressure roller, the molten metal realizes intergranular bonding, and after cooling, forms a firm butt weld. It is made by easy welding 0317 standard model 6012 and steel mother 755 mild steel. Steel pipes are subjected to experiments such as hydraulic pressure, bending, and flattening, and have certain requirements on surface quality. Usually, the length of delivery is 4-10m, and fixed-length (or double-foot) delivery is often required. The specifications of the welded pipe are expressed by the nominal caliber (mm or inch). The nominal caliber is different from the actual. Welded pipe has two types: ordinary steel pipe and thick steel pipe. The steel pipe is divided into threaded and non-threaded according to the end of the pipe.
The submerged arc welding straight seam steel pipe adopts the submerged arc welding technology, which uses filler welding to protect the particles from flux submerged arc. The caliber of production can reach 1500mm. LSAW is the English abbreviation of submerged arc welded straight seam steel pipe. The production process of submerged arc welded straight seam steel pipe has JCOE forming technology and rolled submerged arc welding technology. When the caliber is large, it may be rolled with two steel plates, which will form a double weld. The standards that can be implemented are GB / T3091-2008 low-pressure fluid steel pipe production standards, GB / T9711.1-2-1997 oil and gas steel pipe production and use standards, and the API 5L pipeline steel pipe execution standards of the United States. Production materials: Q19-Q345E; 245R; Q345QA-D; L245-L485; X42-X70. The bearing parameters are mainly 2ST / T, S is the yield strength, and T is the wall thickness. Submerged arc welding has been developed into two-wire submerged arc welding and multi-wire submerged arc welding, which further improves the efficiency.
Straight seam steel pipe can be divided into high frequency straight seam steel pipe and submerged arc welded seam steel pipe according to the production process. Submerged arc welded straight seam steel pipes are further divided into UOE, RBE, JCOE steel pipes according to their different forming methods. The following describes the common high-frequency straight seam steel pipe and submerged arc welded straight seam steel pipe forming processes.