and there are cracks after rolling.Impact toughness the load acting on the machine part at a great speed by QB is called impact load, and the ability of metal under impact load is called impact toughness.Chuangu,When the square tube is covered, the surface of the square tube shall be ventilated to avoid the collection of water vapor on the surface due to difficult volatilization.For gas transmission: gas, steam and liquefied petroleum gas.Hersingh, square pipe welding has many advantages mainly because of the exothermic reaction, the material only needs to be heated below the melting pointIn this period, the technology of continuous rolling pipe was not mature.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.

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, corrugated square pipe, special-shaped square pipe,ChuanguGalvanized strip round pipe factory, 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, machinery industry, chemical industry, steel structure, shipbuilding, automobile, 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, steel pipe with equal side length. It is made of rolled strip steel after process treatment. Generally, leveled crimped and welded to form a round pipe, then rolled into a square pipe from the round pipe,ChuanguSquare tube rectangular tube, 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.The raw material for rolling square tube is round tube blank. For a long time, square tube, rectangular tube, seamless square tube, galvanized square tube and galvanized tube have complete products excellent quality and favorable price. The round tube embryo shall be cut and processed by cutting machine, and the blank with a growth of about m shall be brought to the furnace for heating. The billet is sent to the furnace for heating at a temperature of about degrees Celsius. The fuel is hydrogen or acetylene. The temperature in the furnace is the key problem. After the round tube billet is discharged from the furnace, it should be pierced through the pressure piercer. Generally, the more common piercer is the conical roll piercer. This piercer has high production efficiency, good product quality, large perforation expansion and can wear a variety of steel grades.Square tube production most square tube processing is square tube pressure processing, resulting in plastic deformation of the processed steel (billet, ingot, etc.). According to the square tube processing temperature, the square tube can be divided into cold processing and hot processing. The main processing of square tube includes: rolling: the gap (various shapes) between the square tube metal blank and the rotating roll , because of the compression of the roll, the material section is reduced and the length is increased. This is a common production method for producing square tubes. It is mainly used to produce square tube profiles, plates and tubes. It is divided into cold rolling and hot rolling.Test results,High quality steel (P & le; .%, S & le; .%)If there is only a single plane weld,Chuangu159 galvanized square pipe, the step-by-step back welding shall be adopted from the middle, that is, the arc of the section weld shall be terminated at the section arc.Principle of cold drawing strengthening: the lattice defects of steel increase during plastic deformation, and the serious distortion of defect lattice will hinder the progress and slip of lattice, so the yield point of steel increases and the plasticity and toughness decrease. Due to the internal stress in plastic deformation, the modulus of steel decreases. The cold drawn reinforcement is stored at room temperature for ~ d or heated to ~ ℃ and maintained for a fixed time. This process is called aging treatment.

There are many ways of ignition, such as arc, electric spark, flame, strong current, high-temperature furnace, electron beam, high-temperature radiation, microwave chemical furnace, etc.Direct labor,The disadvantage of empty bending is that when the upper side and side are synchronously empty bending, the forming force is easy to exceed the critical point due to the pressure generated by the upper roll and the lower roll at the same time, resulting in edge instability and concave, and will also affect the stable operation and forming quality of the unit. This is also the different characteristics of qb square tube and round tube empty bending. The concept of square tube: square tube is the pressure processing of ingot, billet or square tube Make materials of all shapes, sizes and properties we need.Square tube failure. When the pipeline is erected, it is necessary to do a good job or directly use the square pipe. The reason for the corrosion of the pipeline is that the layer of the pipeline is damaged. Once the layer is separated from the pipe surface, it will naturally cause failure.With the progress of the times and the faster and faster economic development, the places where large-diameter seamless square tubes are used are becoming more and more popularChuangu,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 bending can also bend the inner corner of r.t without breaking the tube wall.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 bending can also bend the inner corner of r.t without breaking the tube wall.Carbon steel classified by chemical composition: square tube A. low carbon steel (C & le; .%); b. Medium carbon steel (C & le; . ~ .%); c. High carbon steel (C & le; .%).