The method of forming a square tube, solid curved bend reality, as the name suggests is a compact folding, real-bend tube outer wall and the inner and outer roller compacted bidirectional. 1) The real advantage is that the rebound of small curved, forming an accurate, precise and long roll, inside corner molding R more accurate. 2) there is a drawback of real curved stretch / thinning effects. First daqiuzhuang galvanized square and rectangular tube, bent at the real causes tensile bending, stretching effect of the longitudinal length of the bend lines shortened; second, the real turning point curved metal thinning due to stretching. 2, empty air bend bend formed by unidirectional moment outside contact with the tube wall so that the roller strip bending, air bend bending line will produce compression, bending line longitudinal elongation effect makes q345 galvanized square and rectangular tube bent at the metal accumulation appear thicker, which is compressed air bend / thickening effect. 1) the advantage is that you can bend the empty side of the square and rectangular tube bending q235b galvanized in real time can not be bent, such as square and rectangular tube on top / side of sync bending and finishing. Empty bend can also bend R <0.2t inside corners without wall fracture. Disadvantages 2) air bend is when the top / side of sync empty curved galvanized square and rectangular tube, the upper and lower rollers while generating pressure molding force easily surpass the critical point, causing instability concave edge, and also affect the stable operation of the unit and forming quality. This is also the moment when the tube and the tube side air bend forming different characteristics. Hardness is a measure of square tube of soft and hard metal material extent pointer. Production method for measuring the hardness of the most commonly used currently is the indentation hardness method, it is certain geometry indenter under a certain load pressed into the metal material surface to be tested, to determine the hardness value according to the degree of being pushed. Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC) and Vickers hardness (HV) and other methods commonly used method. The fatigue strength of the front side of the tube discussed, plastic, metal hardness are under static loads and mechanical properties pointers. In fact, many machine parts are working under cyclic loading, part under such conditions will produce fatigue. Toughness square tube with great speed on the load acting on the parts called impact load, ability to resist damage metal in impact loading called toughness. q235b _ galvanized galvanized square and rectangular tube Rectangular Pipe Price (certified) _ galvanized square and rectangular tube provided by the Tianjin Steel Pipe Co., Ltd. Rong thousand. 1000-Tianjin Steel Pipe Co. (www.tjqrgg.com) is Tianjin, steel leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In the 1000-pipe leading the staff warmly welcome all inquiries negotiations to create the 1000-pipe a better future.