Xingtai special rectangular tube manufacturer wholesale direct production
（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 ℃.
Xingtai special rectangular tube manufacturer wholesale direct production
1. The surface of the square tube is more durable, with rust prevention treatment and rust prevention treatment. The air oxidation rate is not easy to be too fast, and it is not easy to produce white rust on square steel pipes. 2. It has the characteristics of corrosion prevention and wear resistance, making the service life of seamless steel pipe longer. 3. Seamless steel pipe is under maintenance. After heating, hot galvanizing treatment shall be carried out for each position of seamless steel pipe, and maintenance shall be carried out for convex and concave positions. 4. As the seamless steel pipe is externally hot-dip galvanized, the time of external brushing or external brushing is saved, and the project construction is more convenient. 5. The hot-dip galvanized steel pipe will not freeze even within 39 days, which is very suitable for northern regions. At the time of project acceptance, the key is to pay attention to the four corners of the square pipe, and the four sides are biased within the scope of the national specification. The national specification for seamless square pipe drawing is generally GB/T3094-2008, which also regulates the size error of the R angle. Bright square steel pipes are much better than straight seam square steel pipes in terms of accepting pressure, and the price of bright square steel pipes is much higher at least, When Liangtang square steel pipe is consumed and processed, it will show the situation of the end of the pipe being shrunk. Choosing the end to end is a supplementary countermeasure.
Xingtai special rectangular tube manufacturer wholesale direct production
1. Seamless square tube electrochemical coloring method: refers to the color of the film formed by electrochemical oxidation in a specific solution. 2. High temperature oxidation coloring method: immerse the workpiece in a specific molten salt and adhere to the corresponding process parameters, so that the profiled tube can form a certain thickness of oxide film and show various colors. 3. Chemical oxidation coloring method: refers to the color of the film formed by chemical oxidation in a specific solution, including salt method, mixed sodium salt method, sulfuration method, acid oxidation method and alkaline oxidation method. The common bacteriological method is widely used, but to ensure the color difference of a batch of products, reference electrodes must be used for control. 4. Gas phase cracking coloring method: it is relatively complex, and is rarely used in the industrial consumption of seamless square tubes. 5. Chemical method of ion stacking oxide coloring method: put the stainless steel seamless square tube in the vacuum coating machine to stop vacuum evaporation coating. This method is suitable for processing large quantities of products because of its large investment and high cost.
Xingtai special rectangular tube manufacturer wholesale direct production
Seamless square tubes pass through the tube blank sawing section of the steel mill, and then are heated - perforated - sized - straightened - cooled - slugged - packaged in the annular furnace to become qualified waste products. Generally, it is impossible to place so many stock items in the consumer workshop when they are sent to the user, which requires dealers to place some stock items. However, dealers generally do not have large indoor warehouses, and some costs are too high, which is not cost-effective. Most of them are outdoor warehouses. If the seamless square tubes are placed outdoors, they will be exposed to the wind and the sun. The so-called floating rust literally means a layer of rust floating on the seamless square tube, which can be removed with a towel or other things. Simply speaking, floating rust is also considered as no rust, which belongs to the normal state. The rusting of seamless square tubes is a long-term problem. At least for more than one year, the seamless square tubes that have been exposed to the wind and the sun outside have large and small pits on them, which is the only difference between the floating rust and rusting of seamless square tubes.
