Taiyuan large diameter rectangular tube manufacturer wholesale direct sales manufacturer
1. Fake rectangular tubes are easy to fold. 2. The surface of fake and inferior rectangular tubes is often pitted. 3. The appearance of fake and inferior rectangular tubes is easy to produce scars. 4. The appearance of fake and inferior materials is easy to crack. 5. Fake rectangular tubes are easy to scratch. 6. The fake and inferior rectangular tube has no metallic luster and is light red. 7. The transverse reinforcement of fake and inferior rectangular tubes is thin and low, which often shows the phenomenon of being insufficient. 8. The cross section of the fake rectangular tube is oval. 9. The composition of steel is average, the tonnage of the cold shear is high, and the end face of the cutting head is smooth and uniform. 10. The material of fake and inferior rectangular tubes contains many impurities, and the density of steel is relatively small. 11. The inner diameter of fake and inferior rectangular tubes fluctuates greatly. 12. The trademark and printing of the tube are relatively standard. 13. The spacing of rectangular pipes with a diameter of more than 16 is more than IM. 14. The longitudinal reinforcement of deformed steel bars made of fake and inferior steel is often wavy.
Taiyuan large diameter rectangular tube manufacturer wholesale direct sales manufacturer
1. Pay attention when customers choose square tubes! Choose the right square tube for your request. 2. Some anti-corrosion measures shall be taken for pipes during operation. 3. Do not overload when using. For example, only by weighing can you be overweight. 4. Do not weld or pull bridge wires on the pipe at will, which may cause damage and defects to the pipe. 5. It is important to pay attention to whether the pipes are intact and whether the quality meets the national standards when choosing to purchase. Can we disagree with your request.
Taiyuan large diameter rectangular tube manufacturer wholesale direct sales manufacturer
（1） Slender pipes shall be vertically hung and heated in salt bath furnace or well furnace as far as possible to reduce deformation caused by self weight. （2） When pipe fittings with different section sizes are heated in the same furnace, small pieces shall be placed at the outer end of the furnace, and small pieces shall be taken out of the furnace first. （3） Each charging amount shall be consistent with the power of the furnace. When the charging amount is large, the temperature is easy to be pressed, and the heating time needs to be extended. （4） For square tube quenched with water or salt water, the quenching temperature is taken as the lower limit, and for quenched oil or molten salt, the quenching temperature is taken as the upper limit. （5） During dual medium quenching, the time of staying in one quenching medium shall be controlled according to the above three methods. The time of moving from one quenching medium to the second quenching medium shall be as short as possible, and 0.5-2s is appropriate. （6） Pipes that are not allowed to be oxidized or decarburized on the external surface shall be heated in calibrated salt bath furnace or maintenance atmosphere furnace. If conditions are not available, it can be heated in the air resistance furnace, but protective measures shall be taken. （7） After the square tube is vertically immersed in the quenching medium, it does not swing, but moves up and down, and stops stirring the quenching medium. （8） When there is a lack of cooling ability in the part with high pipe hardness requirements, the part can be sprayed with liquid cooling while immersed in the quenching medium as a whole to improve the cooling speed. （9） It must be placed in the effective heating area. The charging amount, charging method and stacking method shall ensure that the heating temperature is evenly divided, without distortion and other defects. （10） When heating in the salt furnace, do not get too close to the electrode to prevent partial overheating, and the interval should be more than 30mm. The distance from the furnace wall and the immersion depth below the liquid level shall be more than 30mm. （11） During step quenching, the quenching temperature can be properly increased to increase the stability of austenite in rectangular tube and avoid its formation into pearlite. （12） Structural steel and carbon steel can be directly put into the furnace with quenching temperature or 20-30 ℃ higher than quenching temperature for heating. High carbon and high alloy steel shall be preheated at about 600 ℃ before rising to quenching temperature. （13） The quenching temperature can be improved properly for pipes with deeper quenching layer, and lower quenching temperature can be selected for those with shallower quenching layer. （14） The cooling water of rectangular tube shall be free of oil, soap liquid and other dirt. Under normal conditions, the water temperature shall not exceed 40 ℃, and the oil temperature shall not exceed 80 ℃.
Taiyuan large diameter rectangular tube manufacturer wholesale direct sales manufacturer
In the process of bending, the tightening of the square tube moment produces bending deformation, while the internal and external square and rectangular tubes, the inner wall of the two-way real pressure state roll, however, must be based on professionals. The main advantage of real bending is relatively small rebound, and it is very accurate when forming. In the data of its roll shape, ordinary internal angle forming and more accurate. However, these two methods have one defect, that is, the bending of rectangular tubes is always true, which can stretch and reduce the length and thickness of ordinary stretching. However, in the process of empty bending, it is the compressed line of the bent rectangular tube, and the length of the bent line will be lengthened after it is generated, which will produce thickening effect with empty bending. The advantage of this method is that no wall damage will occur no matter the internal angle is smaller than R bending. The defect is that the forming force will exceed the load due to the upward and downward pressure at the same time, and will affect the use of tube length. However, in the application of theory, we should try our best to arrange as soon as possible, and choose the right place and correct operation in the construction process.
Taiyuan large diameter rectangular tube manufacturer wholesale direct sales manufacturer
The standards of square tubes are divided into ministerial standards and national standards. The ministerial spiral welded square tubes are divided into SY/T5037-1999 spiral welded square tubes, GB/T9711.1-1999 spiral welded square tubes GB/T9711.2-1999 and other executive standards for square tube and square tube executive standards and size tendency GB/T9711-1997 API Spec 5L SY/T5037-2000 pipe end outer diameter tendency+2.38mm - 0.79mm D<508 ± 0.75% DD ≥ 508 ± 1.00% D ± 1.25% D wall thickness tendency 50815.0% t12.5% tD ≥ 508 ＋ 17.5% t-10.5% t D<508 ± 12.5% tDC508 ± 10.0% t ± 12.5% tweld reinforcement ≤ 3.18mm 0.5-3.0mm inside ≤ 2.0mm outside ≤ 2.5mm straightness ≤ 0.2% L ≤ 0.2% L ≤ 0.25% L pipe end status bevel angle 30 ° -- 35 ° edge clipping 1.59 ± 0.79mm bevel angle ≤ 1.59mm bevel angle 30 ° -- 35 ° edge clipping 1.59 ± 0.79mm bevel angle ≤ 1.59mm bevel angle 30 ° -- 35 °
Taiyuan large diameter rectangular tube manufacturer wholesale direct sales manufacturer
Square and rectangular pipes can be divided into adhesive socket pipe fittings, elastic seal pattern socket pipe fittings, threaded joint pipe fittings and flange connection pipe fittings according to different connection modes. Pipe fittings can be divided into injection molding pipe fittings and pipe bending molding pipe fittings according to different processing methods. Reduction coefficient of nominal pressure and temperature Since plastic products are relatively sensitive to pressure and temperature, the nominal pressure (PN) of regular rectangular tube refers to the large working pressure when 20 C water is recommended. When the water delivery temperature is different, the working pressure shall be corrected according to the given reduction coefficient (f) for different temperatures, that is, the reduction coefficient shall be used to obtain the large allowable working pressure at the nominal pressure. The internal surface of various pipe fittings shall be lubricated and no delamination is allowed. Obvious bubbles, lines, cold spots, uneven color and other defects. For injection molded square and rectangular pipes, the wall thickness of the main body outside the socket joint shall not be less than the wall thickness of the pipe with the same specification and pressure grade: the uniform outer diameter of the pipe socket shall conform to the rules for the uniform outer diameter and deviation of the pipe in. The types and technical requirements of pipe fittings are economical. The sizes of each part of the pipe fittings are not listed. When required, product samples can be obtained from the ordering manufacturer. Adhesive socket pipe fittings. Elbows, tees, and fittings. The model drawing of the nominal outer diameter of the bonded socket elbow, tee and joint.
