Hardness 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.Large diameter qb square tube production standard classification square tube is divided according to production standard: national standard square tube, Japanese standard square tube, British standard square tube, American standard square tube European standard square tube and non-standard square tube.Pidras nigras,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, which is mainly used for plane beams under static load and bending stress For the frame structure with stress, 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 %.Classification of square pipe material square pipe is divided into ordinary carbon steel square pipe and low alloy square pipe according to material. Ordinary carbon steel is divided into Q Q q SS, # steel, # steel, etc; Low alloy steels are divided into q Mn Q, St-, etc.Ad Dawadimi,Precision inner diameter square tubes for hydraulic and pneumatic cylinders (gb-) are cold drawn or cold-rolled precision square tubes with precision inner diameter for hydraulic and pneumatic cylinders.Stage ( & mdash; )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).

C. special performance steel: (a) stainless and acid resistant steel; (b) Heat resistant steel; (c) Electric heating alloy steel; (d) Electrical steel; (e) High manganese wear resistant steel.Performance index analysis of square tube - plasticity refers to the ability of metal materials to produce plastic deformation without deformation under load.Steel for construction and engineering according to the classification of use without phase transformation or partial phase transformation of square tube: A. ordinary carbon structural steel; b. Low alloy structural steel; c. Steel reinforcement.Total quality management,Ferrous metals refer to iron and iron alloys. Such as steel pig iron, ferroalloy, cast iron, etc. Steel and pig iron are alloys based on iron square tube and carbon as the main added element, 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.Generally, chemical and electrolytic methods are used

Hardness 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.Inspection requirements,For oil, the oil brush work shall be carried out in accordance with the requirements of the rule system, so as to ensure the oil brush and the oil in the correct position of the brush and avoid wrinkles.The strength, plasticity and angle discussed later are the machine function indicators of metal under static load. In practice,Pidras nigras4 galvanized square pipe, and the whole opportunity is tired in this environment.Spraying (throwing) derusting spraying (throwing) derusting is that the high-power motor drives the spraying (throwing) blade to rotate at high speed, so that the steel sand, steel shot, iron wire section,Pidras nigras8 galvanized square pipe, minerals and other abrasives can be sprayed (thrown) on the surface of the square tube under the action of centrifugal force, which can not only completely remove rust, oxides and dirt, but also the square tube under the violent impact and force of abrasives, It can also achieve the required uniform roughness.Pidras nigras,During the pushing process of spot welding and repair welding elbows, there will be thinning, so manufacturers usually use thick spot pipes. If thin raw materials are used, the products produced must be unqualified. Generally, there are about wires thinned. If the technology is not good or the drawn pipe is used, the thickness is significantly lower than the standard.Square tube, modified square tube, square tube, QB square tube and hot-rolled square tube are qualified in quality inspection. The manufacturer adopts advanced equipment to ensure the quality of each product. Magnetic flux leakage testing for surface defects of square tubes is very similar to magnetic particle testing for square tubes, and its scope of application,Pidras nigrasHot dip galvanized seamless pipe, sensitivity and reliability are stronger than magnetic particle testing. Indirect square forming process the traditional forming process of cold-formed square pipe is to gradually roll the hot-rolled steel coil multi stand forming unit into round pipe at room temperature, and then the shaping unit will roll the round pipe into square pipe, which is suitable for rolling small and medium-sized products. Rolling with this process & ldquo; Superb & rdquo; Square tube will show its inherent defects. Because the roll work in the bending process of this process is always concentrated at the point, excessive stress concentration often shows microcracks in the bending process of profiles, which will lead to cracking in serious cases. The products with such defects have serious consequences when they are used in building steel structures. The study of the broken square tube column in the Hanshin earthquake in Japan shows that the corner microcrack is the main cause of the square tube fracture. At the same time, due to the different forming bending radians of products with different wall thickness, the universality of rolls is limited. The large-size cold-formed square tube used in the process adopts the advanced & ldquo; Direct Square & rdquo; The production process is to directly roll the hot-rolled steel coil into a square and rectangular shape at room temperature.In this period, the technology of continuous rolling pipe was not mature.