The disadvantage of empty bending is that during synchronous empty bending at the upper and side, due to the pressure generated by the upper roll and the lower roll at the same time, the forming force is easy to exceed the critical point. All kinds of square tubes, square rectangular tubes, seamless square tubes, galvanized square tubes and galvanized tubes have formal qualifications. Welcome to telephone inquiry and sincerely invite cooperation! It will cause edge instability and concave, and will also affect the stable operation of the unit and forming quality. This is also the different characteristics of qb square tube and round tube empty bending.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).Delta,The welding sequence is to reduce deformation. The welding sequence of rectangular butt welding shall adopt layered and symmetrical skip welding from the middle to both sides according to the following principles. The welding deformation is smaller than that of straight through welding, which is conducive to the dispersion and release of stress and avoid complex stress in weldments. During straight through welding, the narrow plastic deformation zone formed at the beginning of welding only occurs once. Moreover, due to continuous welding, the heat input is large, the heating area is large, and the plastic deformation area caused by compression is large, so the shrinkage deformation after welding is very large. In case of layered and segmented skip welding, the section of each layer is very small,DeltaSpecification and model of galvanized pipe, and the heat required is small, and each layer is divided into several sections for skip welding. Each welding section basically re establishes the secondary temperature field on the cold steel plate and a narrow plastic deformation zone appears each time. Therefore, the average width of the plastic deformation zone (i.e. the size of transverse shrinkage) is smaller than that of the corresponding layered straight through welding, and the longitudinal shrinkage is also smaller, The welding deformation is smaller than that of continuous filling.Improve the positioning and pre bending steps, if necessary, to ensure that the web hunting problem does not occur when pressing parts. Change the shape of the surface pressure of the material to ensure the quality of the parts and avoid the non movement of the surface shape of the roll gap,Delta25 galvanized round pipe, resulting in uneven walking feeding.San Lorenzo,Alloy steel: A. low alloy steel (total alloy element content & le; %); b. Medium alloy steel (total alloy element content > ~ %); c. High alloy steel (total alloy element content > %).It is the process of drawing the die hole of the rolled metal blank (shape, pipe product, etc.) into a section to reduce the length and increase. It is mostly used for cold processing.The advantage of empty bending is that it can bend the side length when the real bending cannot be carried out, such as synchronous bending and finishing of the upper side and side of qb square tube. Empty bend can also bend R & amp; amp; lt; .T without fracture of pipe wall.

It should be noted that the position of the disc from the calibration line can be adjusted according to the reinforcement diameter, and R and R can be equal or different.The painting of the square tube has to go through a process, which requires us to conduct comprehensive consideration and analysis. In particular, the quality and level of the paint and the relevant technical level deserve our attention. Note that the square tube should not be used immediately after painting, but should be placed for a period of time and wait until the paint is dry!B. converter steel: (a) acid converter steel; (b) Basic converter steel. Or (a) bottom blown converter steel; (b) Side blown converter steel; (c) Top blown converter steel.Workshop cost,Normalized: A. pearlite steel; b. Bainitic steel; c. Martensitic steel; d. Austenitic steel.Section shape classification of large-diameter qb square tube square tube is classified according to section shape: simple section square tube & mdash& mdash; Square tube, rectangular tube and complex section square tube & mdash& mdash; Flower shaped square pipe, open square pipe,Delta3x4 square tube, corrugated square pipe, special-shaped square pipe, large-diameter qb square pipe surface treatment classification square pipe is divided according to surface treatment: hot-dip galvanized square pipe, electro galvanized square pipe, oil coated square pipe, acid pickling square pipe, large-diameter qb square pipe purpose classification square pipe is classified according to purpose & mdash& mdash; Square tubes for decoration machine tool equipment, chemical industry, steel structure, shipbuilding, steel beam and column, special purpose, large-diameter qb square tube wall thickness classification, large-diameter qb square tube according to wall thickness Classification & mdash& mdash; Super large diameter qb square pipe, large diameter qb square pipe and thin-wall large diameter qb square pipe rectangular pipe are the names of square pipe and QB square pipe, that is, the strip steel is unpacked, leveled, crimped and welded to form a round pipe, then rolled into a square pipe from the round pipe, and then cut into the required length. Usually pieces per bag. Qb square pipe, also known as square and rectangular cold-formed hollow section steel, is referred to as square pipe and rectangular pipe, code f and j respectively. The allowable deviation of wall thickness of qb square pipe shall not exceed plus or minus % of nominal wall thickness when the wall thickness is not greater than mm, plus or minus % of wall thickness when the wall thickness is greater than mm, except for the wall thickness of corner and welding joint area.So flat, and the size and thickness are not standardized, it can reflect that this square tube is a poor product& rdquo;

Purpose of square tube the purpose of square tube includes construction, machinery, steel construction and other projects, shipbuilding, solar power generation support, steel structure engineering, electric products ( pieces)Energy costs,Square tube heating process square tube calculates the chip thickness of workpiece. After each regrinding, the service life of the saw blade. Regrinding times of the saw blade. When the saw blade is replaced, the main drive AC motor spindle rotates stepless speed change AC motor feed capacity stepless speed change feed fast return to a constant value center system brush device hydraulic saw cutting system system system represents the quality RA flatness, large burr height cutting Chip length tolerance dimension: width and length . ~ .mm ~ m ~ ~ min kW ~ rpm ( kw ~ mmmin mmmin .kw .kw & times; kW S & mu; m . mm & plusmn; mm about mm about mm about mm high. The total weight of each billet square tube is seconds (including, pipe blank cutting, saw blade return, opening device, pipe blank discharge, head and tail cutting time, but excluding pipe blank transportation time). The large production capacity of the three saws is T / A. the pipe blank saw has a special reversing device (hydraulic servo device) to reduce vibration and improve the service life of the saw (only during feeding). The sawing machine has two devices distributed at the inlet and outlet (the input area is supported by roller table to ensure the bending of billet) The inlet end after sawing. Open it to ensure that the saw blade does not contact the blank when it returns. & mdash; feed saw gear & mdash; saw gear vibration reduction, as a movable vibration reduction to avoid the axial of the saw blade. & mdash; brush and sweep device & mdash; a driving brush and sweep device is installed at the bottom of the saw blade to clean the iron filings on the teeth and will not affect the service life of the saw blade. &Mdash; saw blade. In order to improve the service life of the saw blade, a small amount of high load agent container is atomized by air and poured on the saw blade without residue. & mdash; saw blade cooling device. A special nozzle is used to spray cold air at - oC on the saw blade. The cut-off blank is transferred to the buffer chain in front of the loader after passing through the outlet roller table and weighing device (Note: # before sawing, there is a feeding bench for single size billets that need to be cut, and after weighing, and the weighed unqualified billets are transported from the roller table to the removal bench for removal.Large fillet radius, insufficient blank holder area easy to produce unstable wrinkles; If the fillet is too small, the resistance of the material into the die will increase in the deformation process, and the material is not easy to move and transfer inward, which may lead to tensile cracking.Put the pig iron for steelmaking into the steelmaking furnace according to the specified process to obtain steel. The products of steel include ingots, continuous casting billets and various steel castings made of straight square tubes. Generally speaking, steel refers to the steel rolled into various square tubes. Square tube steel belongs to ferrous metal, but steel is not completely equal to ferrous metal.Delta,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).When sand blasting or manual mechanical derusting is used, due to the falling off of the oxide scale of the galvanized square pipe, the metal on the surface of the galvanized square pipe is directly exposed in the air. If a primer is not applied in time, the surface of the galvanized square pipe is easy to rust again affecting the adhesion of the paint film. I am engaged in all kinds of square tubes, square rectangular tubes, seamless square tubes, galvanized square tubes, galvanized tubes and other materials all year round. I operate in good faith. Welcome to call! As the paint is a time-effective material, the overstock of inventory is easy to expire. Therefore, the main indexes of the paint must be rechecked before use and the paint can be used only when the results meet the standards.Fake and shoddy square tubes are easy to scratch, because the equipment of fake and shoddy material manufacturers is simple and easy to produce burrs and scratch the surface of square tubes. Deep scratches reduce the strength of square tubes.