the unqualified ones shall be selected, and double the number of samples shall be taken from the same batch of square tubes for re inspection of unqualified items. If the re inspection results (including any index required by the test of the project) are unqualified, the batch of square tubes shall not be delivered. If the following inspection items fail to pass the preliminary inspection, re inspection is not allowed: A. There are white spots in the low magnification; b. Microscopic.Dahaon, because Baosteel's materials are subject to grade flaw detection, and the density of steel is relatively good. After cold drawing and heating, it is convenient to line up. The steel is cold drawn at room temperature to produce plastic deformation, so as to improve the yield strength. This process is called cold drawing strengthening. Square tube is generally used for product parts with high requirements. It has good willfulness and strength. The surface is better after cold drawing. Cold drawing principle.Lop Buri,The other is designed with deformation angle, which can be regarded as DEG from round tube to square tube; To & deg; The bending deformation of angle, so the deformation angle & theta; It can accurately reflect the deformation degree of corners and edges. In the design process, considering the influence of dimensional accuracy and metal work hardening, the distribution of deformation angle is usually larger at the beginning and middle passes, and then gradually decreases. In the pass formed directly by arc intersection, the fillet part of the pipe blank cannot be filled with the pass, so the pass perimeter is different from that of the pipe blank. In order to ensure the dimensional accuracy, the fillet part of the pass needs to be corrected and calculated. Therefore, this method has higher design accuracy than other methods. However, due to the large amount of iterative calculation,Dahaon6-inch galvanized square pipe, this method is more suitable for pass design by computer. If you use a frame that deforms both horizontally and vertically, you can directly use the deformation angle & theta; Pass design.If there is only a single plane weld, that is, the arc of the section weld shall be terminated at the section arc.The load of impact toughness acting on the parts at a great speed is called impact load. It is specialized in products and renewable resources. Its business includes: square tube square tube,Dahaon114 galvanized square pipe, seamless square tube, galvanized square tube and galvanized tube. The ability of metal under impact load is called impact toughness.

The second is the pickling of the square pipe. Both chemical and electrolytic methods are used when pickling the square pipe. These two methods can remove the oxide skin of the square pipe.On the basis of thermodynamic calculation, the quality assurance of square tube, rectangular tube, seamless square tube, galvanized square tube and galvanized tube is professional. New and old customers are welcome to consult during the preferential activities. The process conditions of calcium treatment of CrMo sulfur-containing square tube are analyzed, and the sulfur-containing gear rolled products after calcium treatment are sampled and studied. The conclusions are as follows: in order to minimize the generation of Cao in sulfur-containing square tube steel, Omega in molten steel; (O) It must be taken off to & times; The rate of calcium can only be guaranteed below -.According to metallographic classification, the annealed state of square tube: A. hypoeutectoid steel (ferrite + pearlite); b. Eutectoid steel (pearlite); c. Steel precipitation through a common square tube (pearlite + cementite); d. Ledeburite steel (pearlite + cementite).High value,For structure: as pile driving pipe and bridge; pipe for wharf, road and building structure, marine pile driving pipe, etc.Square tube is an essential material for the construction and Realization of industrialization. It is widely used and has a wide variety. According to different section shapes, square tube is generally divided into sections, plates, pipes and metal products. In order to facilitate the production, ordering and supply of square tube and do a good job in operation and management, it is also divided into heavy rail light rail, large section steel medium section steel, small section steel and square tube cold bending Section steel, high-quality section steel, wire rod, medium and thick steel plate, sheet steel, electrical silicon steel sheet, strip steel, seamless steel pipe square pipe, welded steel pipe, metal products, etc.The second is to clean the surface of the opposite pipe. When cleaning the opposite pipe, the surface should be cleaned with solvent or emulsion. Square pipes of various specifications, square rectangular pipes, seamless square pipes galvanized square pipes, galvanized pipes are supplied in time and cost-effective. They have become the preferred brand of many wire products. Welcome to buy! It is used to remove oil and dust. It is only suitable for removing grease and dust on the surface of square pipe, which can not remove rust and oxide scale. Therefore, it can only be used as an auxiliary means in production.

Brinell hardness (HB), Rockwell hardness (HRC) and Vickers hardness (HV) are commonly used.investment,For transportation: water supply, drainage, sewage treatment engineering, mud transportation, marine water transportation.The surface compressive stress characteristics of the square tube will be obtained after isothermal quenching.Square tube is an essential material for the construction and Realization of industrialization. It is widely used and has a wide variety. According to different section shapes, square tube is generally divided into sections, plates,Dahaon35 galvanized square pipe, pipes and metal products. In order to facilitate the production, ordering and supply of square tube and do a good job in operation and management, it is also divided into heavy rail, light rail, large section steel, medium section steel, small section steel and square tube cold bending Section steel, high-quality section steel, wire rod, medium and thick steel plate, electrical silicon steel sheet, strip steel, seamless steel pipe, square pipe, welded steel pipe, metal products, etc.Dahaon,C. electric furnace steel: (a) electric arc furnace steel; (b) Electroslag furnace steel; (c) Induction furnace steel; (d) Vacuum consumable furnace steel; (e) Electron beam furnace steel.At this time, if the welding wire of the same material is used for spot welding where the thickness is insufficient, it shall be welded to the fixed thickness, ground and sandblasted, and repair welding shall be adopted where there are cracks, even if the steel pipe with another large opening can be made up at one time.B. tool steel: (a) carbon tool steel; (b) Alloy tool steel; (c) High speed tool steel.