Yangzhou medium thick wall rectangular tube 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 ℃.
Yangzhou medium thick wall rectangular tube manufacturer
Square pipe is a kind of name for square pipe and rectangular pipe, that is, steel pipes with equal and unequal side lengths. It is rolled from strip steel after processing. Generally, the strip steel is unpacked, leveled, curled and welded to form a round pipe, which is then rolled into a square pipe and cut to the required length. Square and rectangular tubes are also called square and rectangular cold-formed hollow steel sections, which are called square and rectangular tubes for short, and their codes are F and J.
Yangzhou medium thick wall rectangular tube manufacturer
The manufacturing technology of fine steel pipes is very strict. Only a few steel pipe factories can meet the conditions for consumption of fine steel pipes, which leads to the appearance of fine steel pipes in the market, some of which are not really fine steel pipes. Therefore, when we purchase steel pipes, we should know some skills to distinguish fine steel pipes. But for ordinary steel pipes, it is indicated that they are not lubricated enough, and their toughness and torsional strength are not good enough. Once this steel pipe stops flaring or flattening, it is easy to show cracks. When these cracked steel pipes are used in machinery and equipment, they will present falling and broken residues. These residues will enter more and more delicate parts with the use of the equipment, which will affect the speed and progress of the equipment for a long time, presenting various equipment problems. If fine steel pipes are used, this phenomenon will be reduced in greater layers. Fine seamless steel pipe is a kind of high-precision steel pipe material after cold drawing or hot rolling. This allows the pipeline to be free from leakage under high pressure. Even after flaring, flattening and other operations, the pipeline will not show cracks. This ensures the normal operation of the equipment, speeds up the consumption efficiency and improves the overall interests. With the change of time, the supply and demand relationship of the market is also changing from time to time. This is why there are always some new products in the market. Because every industry hopes to have higher quality and higher performance products. In the steel pipe market, the speed of change will be even higher. Especially in recent years, the renewal rate of steel pipes has reached a peak. Under such a background, there are many steel pipes whose quality cannot keep up with this change, which have slowly disappeared. However, there are also some steel pipes that, depending on their quality and application performance, have opened up a larger market space, and fine steel pipes are one of them.
Yangzhou medium thick wall rectangular tube manufacturer
When designing the section of seamless square pipe, two main factors should be considered: one is the safety of the section; The other is the economy of the section. It is feasible to use elastic theory to calculate static structures, such as warehouses, houses, bridges, etc., but it is not suitable for moving components, such as wheels, etc. At this time, people often use plastic theory. The study of plasticity theory can be traced back to 1914. In 1975, the European Design Committee formulated a plastic design standard, which is mainly used for static load plane beams and frame structures subject to bending stress. Its request is as follows: for high-rise buildings, more detailed calculation is required. Under the dynamic load condition, the plastic design method usually stops the calculation of allowable stress by multiplying the allowable stress safety factor by the allowable stress which is not less than the dynamic load. When a shaft is bent, the calculation can be stopped by the formula a=Wmotion/W allowable. Using plastic method instead of elastic method to calculate strength can improve the bearing capacity of members by 14%.
