San-RamonDN25 
HerediaDN25 gaThe normal process flow is as follows: the round steel is perforated to form a tube embryo then pickling is carried out, the black skin on the outer surface is washed off and then grinding is carried out. After passing the inspection, the rolling mill or cold drawing and cold drawing are carried out. Annealing is required for wall reduction, but not for air drawing. After forming, annealing and straightening are carried out, and pickling is tested and stored in the warehouse. Basically, these are the processes. Better manufacturers will perform whitening treatment during annealing to make the surface treatment more beautiful. The narrow blank of square pipe can produce welded pipe with larger diameter, and the blank of the same width can also produce welded pipe with different diameter. However, compared with the straight seam square pipe with the same length, and the production speed is low. Square pipes with large or thick diameter are usually made of steel blank directly, while small welded pipes and thin-walled welded pipes only need to be directly welded with steel strip. Then after simple polishing, straight seam welding is mostly used for relatively welded pipes, and spiral welding is mostly used for large-diameter welded pipes.
Square tube with complex section: flower shaped square tube, open square tube, corrugated square tube and special-shaped square tube.
Madison.Fake and shoddy square tubes are easy to scratch, because the equipment of fake and shoddy material manufacturers is simple and easy to produce burrs and scratch the surface of square tubes. Deep scratches reduce the strength of square tubes.
Galvanized q355b square pipe for low pressure fluid transmission, Standard No.: gbt3092-2008. The representative materials are the same as above. It is mainly used to transport low-pressure fluids such as water, gas, air and oil and add water or steam. The surface of square pipe shall be hot galvanized or cold galvanized.
.After chemical treatment and surface treatment of the square tube, the appearance and quality of the square tube have been improved to another height, making the current square tube present in the market in a good state.
From the perspective of production, the temperature of no open forging and final forging is a comprehensive technical and economic problem. If qualified q355b square tubes can be obtained in the temperature range of the vehicle, reasonable process procedures should be selected from an economic point of view. Obviously, the higher the temperature, the easier the forging and the higher the productivity, but the greater the fuel consumption and the loss of the heating furnace; We should consider these two aspects and make a reasonable choice.
Square tube is in our reality
At the same time, hanging heating shall be carried out during heating to reduce quenching deformation. For high-precision guide rail, gas nitriding or ion nitriding shall be carried out to reduce deformation; Square tubes have outstanding performance in all aspects of performance. We will also test them in this regard when making square tubes more durable. What outstanding performance do square tubes have in mechanical properties? Next, I'll introduce it to you.
Oil drilling pipe (yb528-6) is a square pipe used for internal or external thickening at both ends of oil drilling. Steel pipes are divided into turning wire and non turning wire. Turning wire pipe is connected with joint, and non turning wire pipe is connected with tool joint by butt welding.
Hot rolled q355b square tube continuous casting slab or blooming slab is used as raw material, heated by stepping heating furnace and descaled by high-pressure water into roughing mill. Roughing material enters finishing mill after head cutting, tail cutting and then computer rolling. After final rolling, it is rolled into straight hair coil through laminar cooling and coiler. The head and tail of straight hair curl are often tongue shaped and fish tail shaped, with poor accuracy of thickness and width,MadisonHow much is a galvanized pipe, and there are often defects such as wave shape, hem, tower shape and so on. The coil weight is heavy and the inner diameter of the steel coil is 690mm.
Home page recommendation.The flattening speed of the sample can be 20 ~ 50mmin.
The selected punch and die fillets are related to the magnitude and distribution of stress
The difference between q355b square tube and Q345A is that there are fewer impurities s and P and better low-temperature impact performance. From the welding point of view, when the impurity elements in the base metal are less it is good for welding hot crack.
The cutting surface of the square tube shall be true circle, and the cutting line shall be at right angles to the axis of the square tube. Excessive force is the reason for cutting the square tube into flat or oval, so the square tube should be cut with appropriate force.
Industry management.The service life has a great impact on the isotropic performance of the square tube. The use of secondary refining technology (including vacuum refining,MadisonGalvanized steel square pipe, 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 improve the performance.
The surface of fake and inferior square tubes is easy to produce scabs. There are two reasons: the material of fake and inferior square tubes is uneven and there are many impurities. The guide equipment of fake and shoddy material manufacturers is simple and easy to stick to steel. These impurities are easy to scar after biting the roll.
D. do not cut your hands boring, especially for girls. Holding or fingers will bind themselves.
Madison.After time, the workpiece forms an oxide film with a fixed thickness and presents various colors. Chemical oxidation method is to form various film colors in a specific solution at temperature and time; Because of the law & rdquo; More, but to maintain the color of the product, the reference electrode must be used. Electrochemical method is to form the color of chloride film with fixed thickness in specific electrolyte at temperature, voltage and time. This process is mature and widely used. Ion implantation method is to vaporize ions in vacuum and deposit them on the surface of q355b square tube, such as watch case on the market. The golden color of watch strap adopts this process technology, which is suitable for mass production. The process of gas phase cracking is more complex and less used in industry. Square tube has long been widely used in mechanical industry. When the square pipe is cut automatically, the distance difference between the two ends of one side of the pipe and the guide rail shall be adjusted within 5mm. During semi-automatic cutting, the guide rail shall be placed on the plane of the cut pipe, and then the cutting machine shall be placed on the guide rail gently.
General square pipes are stacked outdoors, and most of them are buried underground when in use, so they are easy to corrode and rust. In order to ensure the smooth flow of the pipeline, square pipes must have strong corrosion resistance. Once the pipeline is corroded, it will cause oil and gas leakage, which will not only interrupt transportation, but also pollute the environment and may even lead to fire and cause harm.
The tensile test is to make q355b into a sample, pull the sample to fracture on the tensile testing machine, and then measure one or more mechanical properties. Usually, only tensile strength,Madison4 points galvanized pipe outer diameter, yield strength, elongation after fracture and reduction of area are measured. Tensile test is the basic mechanical property test of metal materials. Almost all metal materials have specified tensile test as long as they have requirements for mechanical properties. Especially for those materials whose shape is not convenient for hardness test, tensile test has become the only means to test mechanical properties.