In this period, the technology of continuous rolling pipe was not mature.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.Andorra la Vella ,Hardness test is to use a hard indenter to slowly the sample surface according to the specified conditions, and then test the indentation depth or size, so as to determine the hardness of the material. Hardness test is simple, rapid and easy to implement in material mechanical property test. Hardness test is non-linear, and there is an approximate conversion relationship between material hardness value and tensile strength value. The hardness value of material can be converted into tensile strength value, which is of great practical significance.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, this method is more suitable for pass design by computer. If you use a frame that deforms both horizontally and vertically,. fake and inferior square tubes are easy to fold. Folding is a variety of broken lines formed on the surface of square tubes, and this defect often runs through the longitudinal direction of the whole product. The reason for the folding is that the fake and shoddy manufacturers pursue the rate, the reduction is too large, resulting in ears, folding occurs during the next rolling, the folded products will crack after bending and the strength of the square tube will be greatly reduced.Steel used & mdash& mdash; Such as bridge steel, ship steel, boiler steel, pressure vessel steel, agricultural machinery steel, etc.QB square tube is a product appeared in recent years, which mainly has strict tolerance and roughness for the dimensions of inner hole and outer wall. Production process classification of large-diameter qb square tube large-diameter qb square tube is divided into hot-rolled seamless square tube, cold drawn seamless square tube, seamless square tube and qb square tube according to production process. Among them, qb square tube is divided into: (a) by process & mdash& mdash; Arc welded square pipe resistance welded square pipe (high frequency and low frequency), gas welded square pipe and furnace welded square pipe (b) are divided by weld & mdash& mdash; Material classification of straight seam welded square pipe and spiral welded square pipe large diameter qb square pipe: plain carbon steel square pipe and low alloy square pipe. Ordinary carbon steel is divided into Q Q q SS, # steel, # steel, etc; Low alloy steels are divided into q Mn, Q St-, the technology of continuous rolling pipe was not mature.Application of square tube products: for mechanical equipment, solar energy equipment, steel structure, automobile parts, guardrail and ship internal structure.If there is only a single plane weld, that is, the arc of the section weld shall be terminated at the section arc.Workshop cost,The disadvantage of empty bending is that during synchronous empty bending at the upper and side,Andorra la Vella Specification of rectangular galvanized square pipe, due to the pressure generated by the upper roll and the lower roll at the same time,Andorra la Vella Galvanized square pipe manufacturing machinery, 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.After cold drawing and aging treatment, the yield point is improved, the tensile ultimate strength is also increased, and the plasticity continues to decrease. Due to the reduction of internal stress during aging, the modulus can be basically restored. According to this principle, cold drawing or cold drawing of reinforcement or low carbon steel wire rod is often carried out on site or prefabricated component factory, so as to improve yield strength and save steel.The reason why it is divided into two types is that chemical cleaning can only clean the surface very thoroughly, and it is difficult to achieve the desired results in some fine cracks.

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.Latest consultation,Steel pipe for geological drilling (yb-) is a steel pipe used by geological departments for core drilling. It can be divided into drill pipe, drill collar, core pipe, casing, sedimentation pipe, etc.Low alloy steel is divided into q Mn, Q, St-, etc.There are many processing technologies for square tubes. I won't introduce the specific processing technology here. We only know about the processing technology of each other's tubes. We may have insufficient understanding of its heating technology. Next, I'll give you a detailed introduction to the heating technology of the lower tubes.Andorra la Vella ,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.Generally, chemical and electrolytic methods are usedAfter cold drawing and aging treatment, the yield point is improved, the tensile ultimate strength is also increased, and the plasticity continues to decrease. Due to the reduction of internal stress during aging, the modulus can be basically restored. According to this principle, cold drawing or cold drawing of reinforcement or low carbon steel wire rod is often carried out on site or prefabricated component factory