The welding process of square tube is analyzed. The square tube is produced and processed at room temperature with strip steel as raw material. Square pipe can be divided into straight seam welded pipe， square pipe and spiral welded pipe. Due to the different uses of welded pipes， the standards of welded pipes are summarized in turn: galvanized qb square pipe for low-pressure fluid transportation， etc. It is mainly used for conveying water， gas， air，Galvanized pipe oil and heating hot water or steam，180 square tubeWhat are the advantages in the protection industry and is used for general low pressure fluid.
2Square tube is a kind of square tube type. Many materials can form square tube body. It is used for what purpose and where. Most square tubes are steel tubes， mostly structural square tubes， decorative square tubes and building square tubes. Square tubes can be divided into seamless and welded joints. Seamless square tubes are formed from seamless circular tubes.
gImpact toughness the load acting on the machine part at a great speed by QB is called impact load， and the ability of metal under impact load is called impact toughness.
Functional index analysis of square tube - commonly used are square tube Brinell angle (HB)， Rockwell angle (hrahrbhrc) and Vickers angle (HV) Equal angle is a gauge needle to weigh the soft and hard level of metal data. In the current life， the angle method is rarely used to determine the angle. It uses the indenter with a certain number and shape to determine the angle value of the metal data surface being tested under a certain load according to the level.
NPirachikabaOrdinary carbon steel is divided into Q Q q SS， # steel， # steel etc.
AlAt the same time， the heating temperature and heating time will also have a great impact on the performance of square tube. The heating of square tube blank is the key process to ensure that the square tube blank has enough plasticity and complete the smooth perforation. If the heating temperature is too high or the heating time is too long，Galvanized pipe the billet of the square tube will be burned and decarburized， and even the chemical composition of the square tube will be unqualified (unqualified carbon content)， which is easy to cause batch quality problems and seriously affect the product qualification rate.
Both internal and external welding of square pipes are carried out by American Lincoln Electric welding machine for single wire or double wire submerged arc welding， so as to obtain stable welding specifications.
The purity of the square tube has a great impact on the isotropic performance of the square tube. The use of secondary refining technology (including vacuum refining， ESR and ladle powder spraying) can improve the purity of the square tube， especially reduce the content of harmful impurities in the square tube， which is beneficial to improving the performance.
oSteel pipe for geological drilling (yb-) is a steel pipe used by geological departments for core drilling. It can be divided into drill pipe， drill collar， core pipe， casing，Galvanized pipe etc.
FStrength refers to the function that the square tube data is destroyed under static load (appropriate amount of plastic deformation or fracture)， because the action form of load includes tension，180 square tubeWhat are the advantages in the protection industry compression， meandering shear and so on， because the strength is also divided into tensile strength， compressive strength， flexural strength， shear strength and so on. There is often a definite connection between various strengths. In normal use， tensile strength is often used as the fundamental strength gauge.
YQuality riskThere are many forms of heating furnace， which can rotate slowly，Galvanized pipe_ Galvanized square pipe_ Seamless steel pipe_ Square tube - Wuxi Jiahang the blank is loaded along the diameter direction of the furnace bottom from the inlet， and can be heated and homogenized to the specified temperature when it is used at the outlet. The production process of seamless square tube is relatively slow， and the heating operation especially needs patience. Because if the heating operation is not standardized， cracks， folding and eccentricity on the inner or outer surface of the tube blank will only produce waste products and defective products.
fQClassification of surface treatment square pipe is divided into hot-dip galvanized square pipe， electro galvanized square pipe， oiled square pipe and pickled square pipe according to surface treatment.
Be sure to select special for square pipe cutting.
After the square pipe is produced， the surface treatment is generally carried out， that is， the scale， rust， dirt and attachments on the surface of the square pipe are removed. Those that cannot be treated by physical treatment should be treated by chemical treatment.
DiscountxDimensional stability for high-precision square tubes， the required accuracy is high， so the dimensional stability must be maintained. Due to straightening in the air and slow cooling speed， it has the effect of stabilization and will increase the number of residual square tubes in the， so it must be cooled; Reduce quenching deformation because the square tube is slender， it is easy to deform during quenching， so its deformation must be strictly controlled. Heat treatment is a key process. In the process of quenching and cooling， the cold plasticity shall be corrected in time， which is a key step to ensure the improvement of its qualification rate. Therefore， hot bath quenching or cooling in oil for a fixed time shall be carried out to propose thermal correction.
WImpact toughness the load acting on the machine part at a great speed by QB is called impact load， and the ability of metal under impact load is called impact toughness.
Square tube flattening test is a kind of test to check the deformation performance of metal tubes (seamless square tubes and rectangular tubes) flattened to the specified size and show their defects. Relevant flattening tests shall be carried out in accordance with relevant provisions of test standards. Requirements for samples samples can be taken from metal pipes with qualified appearance. Generally sawing is adopted. The inner and outer walls of the pipe shall retain the original surface without any processing. Sample length L & asymp; D (D is the outer diameter of the pipe). When the outer diameter is large， l = mm. When cutting the sample the length l shall not exceed mm. When the outer diameter is less than mm， the surface of the sample shall not be damaged and the performance of the metal shall not be changed due to heating or cold processing. The edge of the section shall be flattened. The flattening test is a test to check the deformation performance of the metal pipe (seamless square pipe and rectangular pipe) flattened to the specified size and show its defects. Relevant flattening tests shall be carried out in accordance with relevant provisions of test standards.
iChemical polishing: less investment in processing equipment， high speed， high efficiency and good durability. Its defects are poor brightness gas overflow， demand for ventilation equipment and difficult heating. It is suitable for processing small batch of disordered parts and products with low brightness demand for small parts.
hKSquare tube is a kind of square tube type. Many materials can form square tube body. It is used for what purpose and where. Most square tubes are steel tubes， mostly structural square tubes， decorative square tubes and building square tubes. Square tubes can be divided into seamless and welded joints. Seamless square tubes are formed from seamless circular tubes.
Qb square pipe for mining fluid transportation， Standard No.: gbt-. The representative material is Q grade B steel， which is mainly used for coal mine air pressure， drainage and vertical shaft gas drainage straight seam qb square pipe.