LSAW Steel Pipe

 　　Porosity, bubbles, shrinkage cavity residues, non-metallic inclusions, segregation, white spots, cracks and various abnormal fracture defects in cold drawn seamless steel pipes can be found through macroscopic inspection. The method of macro inspection is divided into two methods: acid leaching inspection and fracture inspection. A brief introduction to the common macro defects displayed by the acid leaching method is as follows: 　　Causes of segregation: 　　During the pouring and solidification process, the selective crystallization and diffusion caused the aggregation of certain elements, resulting in uneven chemical composition. According to the different positions of the distribution, it can be divided into ingot type, center and spot segregation. 　　Macroscopic characteristics: 　　On acid-leached samples, when the segregation is erodible substances or gas inclusions, it is dark in color, irregular in shape, slightly concave, flat at the bottom and many dense microporous spots. ...

 　　Thick-walled seamless steel pipe has the characteristics of high strength, good hardenability, good toughness, small quenching deformation, high temperature creep strength and high endurance strength. Used to manufacture forgings with higher strength and larger quenched and tempered section than 35CrMo thick-walled seamless steel pipes, such as large gears for locomotive traction, supercharger transmission gears, pressure vessel gears, rear axles, connecting rods, spring clamps, etc. It has a large load and can be used for drill pipe joints, fishing tools and bending machine molds in deep wells below 2000 meters. 　　After the precision bright tube is quenched to obtain the martensite structure, it is tempered in the temperature range of 450-600℃; or after tempering at 650℃, it passes through 350-600℃ at a slow cooling rate; or after tempering at 650℃, 16Mn seamless steel pipe Long-term heating in the temperature range of 350 to 650°C will cause embrittlement of the precision brig...

 　　The welding method of seamless steel tube should be selected according to the material and wall thickness of the seamless tube. Because different welding methods have different arc heat and arc force, different welding methods have different characteristics. 　　For example: Tungsten arc welding is characterized by low current density, stable arc combustion, and good weld formation. It is especially suitable for thin plate welding, but thick plate welding is not an option; plasma arc is characterized by high arc column temperature and high energy density , Plasma arc has good straightness, its rigidity and flexibility have a wide adjustment range, and work is stable, but the operation is more complicated; submerged arc welding has the characteristics of penetration ability and high welding wire deposition efficiency, so the welding speed It can be greatly improved, the welding cost is lower, but the labor conditions and environment are relatively poor. It can be seen that differen...

　　Finishing tube is also called cold rolled precision tube, it is one of the types of seamless steel tube production process. The characteristics of the fine rolling tube: 　　1. The cold rolled precision tube tolerance dimension precision is high, the product accuracy control in the plus or minus 5 mm, inside and outside wall finish good, surface oxide layer. 　　2. The comprehensive performance of cold rolled precision tube is good, can bear high pressure, cold bending, flaring, flattening not crack, not wrinkled skin, can do all kinds of complex deformation and mechanical processing. 　　3. The popularization and application of precision seamless steel pipe steel can save and improve processing efficiency and reduce machining process and equipment investment, can save cost and save machining time, greatly improve the production capacity and material utilization, at the same time to improve product quality, reduce the cost. 　 　Finishing pipe application: 　　Cold rolled precision ...

　　Cold drawn seamless tube is used for high dimensional accuracy mechanical structure, hydraulic equipment and good surface finish cold drawn or cold rolled precision seamless steel tubes. High-precision drawing denotes the outer diameter size precision (tolerance) strict and external surface finish, roundness, straightness good thickness uniformity. 　　Heat treatment of cold drawn seamless steel pipe : 　　(1)cold drawn steel annealing: refers to the metal material is heated to the appropriate temperature, to maintain a certain time, and then slowly cooled heat treatment process. Common annealing process are: recrystallization annealing, stress relieving, ball annealing, fully annealed and so on. The purpose of annealing: mainly to reduce the hardness of the metal material, to improve the plasticity, or cutting processing to Liqie pressure processing, reduce the residual stress and improve the uniformity of microstructure and composition, heat treatment, after possible or tissue prep...

　　Hot rolled seamless steel tube: hot rolling is related to the cold drawn, hot rolling is performed above the recrystallization temperature of the rolling. 　　 Hot-rolled seamless steel tube process: 　　Round tube perforation → heating → three-roll rolling, rolling or extrusion → detached → sizing (or reducing) → cooling → straightening → hydrostatic test (or testing) → mark → storage 　　 Hot-rolled seamless steel tube advantages: 　　Ingot casting can destroy tissue, grain refinement of steel and eliminate defects microstructure, so that the steel dense tissue mechanical properties are improved. This improvement is mainly reflected in the direction along the rolling direction to a certain extent, the steel is no longer isotropic; pouring formed bubbles, cracks and loose, can be welded at a high temperature and pressure. 　　 Hot-rolled seamless stee tube disadvantages: 　　1. After hot rolling, the steel inside the non-metallic inclusions (mainly sulphide and oxide, and silicates)...

    The delivery condition of seamless steel tube is the final plastic deformation or final heat treatment state of the finished product.Hot rolled or cold drawn (rolled) state or manufacturing state, generally not by heat treatment;Heat treatment after heat treatment, or normalizing, tempering, solid solution, annealing, according to the type of heat treatment state.     The state of delivery of the seamless steel tube is usually the state of annealing or the original state of the steel, which facilitates subsequent processing. When ordering, the delivery status must be stated in the contract. Weight delivery status:     Actual weight - at the time of delivery, the weight of its product is delivered according to the weighing (weighing) weight;     Theoretical weight - The weight of the product at the time of delivery is based on the nominal weight of the steel.     http://www.xysteelpipe.com/info/Seamless-steel-pipe-delivery-con...

    Different classification of steel pipe would have different range from width length for each kind of steel pipe like seamless steel pipe, ERW steel pipe, SSAW steel pipe and so on. Today we would like to introduce the specifications range for large diameter steel pipe.     Generally speaking, the large diameter steel pipe has specific character for the diameter. For example, the outer diameter of the steel pipe is usually more than 325mm, and wall thickness of more than 20mm.     However, there are difference for single welded steel pipe and double welded steel pipe.     Single welded steel pipe: At present, the maximum diameter of a single weld steel pipe can reach 1220mm, wall thickness up to 80mm.     Double welded steel pipe: The maximum diameter of the double weld steel pipe can reach 2020mm.     If you need to, you can go to Tianjin Xinyue Steel Group for more details.     http://www.xysteelpipe....

    Differences in manufacturing process:     Galvanized steel pipe and seamless steel pipe is two kinds of steel pipe, galvanized steel pipe surface is galvanized, there may be welded pipe, it may be seamless pipe, seamless steel pipe refers to the manufacturing process, Seamlessly Galvanized pipe corrosion-resistant, seamless steel pipe can withstand higher pressure. Galvanized steel pipe due to the protection of zinc, not easy to rust, galvanized steel pipe than the seamless steel pipe, if it is used for the balcony, it is best to use galvanized light pipe, seamless steel pipe is not suitable for use on the balcony, due to the seamless steel pipe wall thickness, natural weight on the heavy, and the cost of seamless steel pipe than the cost of galvanized steel pipe is high, there are galvanized steel pipe is very durable, the service life is far more than seamless steel pipe. If the quality is excellent, the use of more than 20 years should not be a problem, of...