If there is only a single plane weld, the step-by-step back welding shall be adopted from the middle, the arc of the section weld shall be terminated at the section arc.After spraying (throwing) derusting, it can not only expand the physical adsorption on the pipe surface, but also enhance the mechanical adhesion between the layer and the pipe surface. Therefore, spray (throwing) derusting is an ideal derusting method for pipelines. Generally speaking, shot blasting (sand) is mainly used for the inner surface treatment of the pipe, and shot blasting (sand) is mainly used for the outer surface treatment of the pipe. Several problems should be paid attention to in derusting by spraying (throwing).MontecellioMechanical properties of seamless qb square tube: tensile strength & sigma; b (MPa)：≥ yield strength & sigma; s (MPa)：≥ elongation & Delta; (%)：≥ reduction of area & psi; (%)：≥ impact absorption energy (impact value) (akuj): & Ge; the products produced by the more complex technology are exquisite. At present, whether Fangguan can obtain such a high market evaluation depends on the complex technology of Fangguan.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.Maiduguri Fangguan is highly praised by the public in the market. What is important is that there is a good guarantee in terms of quality. Therefore,Square tube structural steel A. mechanical steel: (a) quenched and tempered structural steel; (b) Surface hardening structural steel: including carburized steel, ammoniated steel and surface quenching steel; (c) Easy to cut structural steel; (d) Steel for cold plastic forming: including steel for cold stamping and steel for cold heading.The principle of straightening machine is that a disc is divided into two sides to clamp round steel straight lines. Professional square tube, square rectangular tube, galvanized square tube, galvanized tube, high price, service, on-site settlement, honest operation! The edge is one with radius r,MontecellioThick galvanized square pipe, and the other outer edge must be two equal diameters with radius R. The diameter of the reinforcement to be straightened is D, and the center distance between them is adjusted to R + R + D.Hardness QB square hardness is a pointer to measure the hardness and softness of metal materials. At present, the hardness method is commonly used to measure the hardness in production. It uses the indenter with fixed geometry to measure the hardness value of the metal material surface tested under fixed load according to the degree of hardness.

Cleaning solvent and emulsion can clean the surface of square tube to remove oil, grease dust, agent and similar organic matter, scale, welding, etc. on the surface of square tube, so it is only used as an auxiliary means in production.The calculation method theory of square tube mechanics is feasible to calculate static structures, such as warehouses, houses and bridges, but it is not suitable for moving components such as wheels. At this time, people often use the plastic theory. The research of the plastic theory can be traced back to . In , the European Design Association formulated D plastic design code, the requirements are as follows:% sigma; B% sigma;% zeta;% ge;% delta;% ge; % for high-rise buildings, more detailed calculation is required. In the case of plastic design, the allowable stress is usually calculated according to the safety factor that the allowable stress is not less than the dynamic load and multiplied by the allowable stress. In the case of bending of an axis, the formula a = w can be used Using plasticity instead of calculated strength can improve the bearing capacity of members by %.A. square tube structural steel: (a) high quality carbon structural steel; (b) Alloy structural steel; (c) Spring steel; (d) Easy cutting steel; (e) Bearing steel; (f) High quality structural steel for specific purposes.Discount,Square tube has a wide range of application fields. Its main field is the construction industry, which promotes the development of economic construction. Because the production process of square tube hole is different, the production design of square tube hole is also different. Next, I will introduce in detail the types of tube hole design below.Special performance steel: A. stainless and acid resistant steel; b. Heat resistant steel: including oxidation resistant steel, heat strength steel and air valve steel; c. Electric heating alloy steel; d. Wear resistant steel; e. Low temperature steel; f. Electrical steel.. 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.

Section shape classification square tubes are classified according to section shape: simple section square tubes & mdash& mdash; Square tube, rectangular tube and complex section square tube & mdash& mdash; Surface treatment classification of flower shaped square pipe, open square pipe, corrugated square pipe and special-shaped square pipe square pipe is divided into hot-dip galvanized square pipe, oil coated square pipe and pickling square pipe according to surface treatment. Square pipe is classified according to purpose & mdash& mdash; Square tubes for decoration, machine tools and equipment, machinery industry, chemical industry, steel structure, shipbuilding, automobile, steel beam and column and special purpose are classified by wall thickness & mdash& mdash; Super square tube square tube and thin-walled square tube plasticity refers to the ability of metal materials to produce plastic deformation (deformation) without deformation under load.Honesty and mutual benefit,Fatigue strength, plasticity and hardness discussed above are indicators of the mechanical properties of metals under static load. In fact, many machine parts work under cyclic load, under which fatigue will occur.Classification of surface treatment square pipe is divided into hot-dip galvanized square pipe,MontecellioQuotation of galvanized square pipe, electro galvanized square pipe, oiled square pipe and pickled square pipe according to surface treatment.If the re inspection results are unqualified (including the items whose preliminary inspection results are unqualified and re inspection is not allowed), the supplier can submit them for acceptance one by one; Or re conduct heat treatment (the number of RE heat treatment shall not exceed times), and propose acceptance with a new batch.Montecellio,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, resulting in uneven walking feeding.Welding is a synthetic gradient material, which can be used as solder to weld special-shaped materials in order to overcome the mismatch of chemical, mechanical and physical properties between base metals.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).