steel tube

　　We talk ERW steel pipe and SSAW steel pipe more than others welded steel pipe before. Today, we would have rounded analysis for the welded steel pipe and then we hope you can know better which kind of welded steel pipe you need to choose. 　　Definition for welded steel pipe: the steel pipe joint, to some extent, would be the symbol for welded steel pipe. Under this situation, we know welded steel pipe is use the steel belt or steel plate material, with the production process of through the bending deformation into round ,square ect then welded into shape. 　　Types of welded steel pipe: With different raw materials, we would make different categories for welded steel pipe. They can be divided into the high frequency or low frequency electric resistance welded pipe and gas welding tube, electric arc one and furnace one. Generally speaking, we would like to call them SSAW, LSAW, ERW steel pipe and so on. 　　Application of welded steel pipe: A joint would make limit for the function o...

　　In recent years, there has been a trend in the world to replace high-cost seamless steel pipes with high-quality welded pipes. This is mainly due to the continuous breakthrough in the production technology of welded pipes, which is reflected in the following aspects: 　　(1) Advances in desulfurization technology have reduced the sulfur content of steel and improved the welding quality of steel pipes. 　　(2) Due to the addition of special elements such as V, Ti, and Nb, the carbon equivalent is lowered, and the toughness and strength of the steel pipe are improved. 　　(3) The application of vacuum degassing technology improves the purity of the tube blank strip, reduces inclusions, and improves the quality of the weld. 　　(4) The development of hot rolling technology has improved the dimensional accuracy of the strip and thus reduced the dimensional deviation of the welded pipe. 　　(5) Improvement of quality inspection methods, such as ultrasonic non-destructive testing, hydrauli...

　　 Welded pipe at the factory to go through rigorous testing to ensure compliance with the provisions of pipe quality standards and user requirements. Pipe inspection items generally include: factory inspection items have the appearance quality, straightness, dimensions, and other types of weld quality inspection items (flattening, flaring, bending, etc.). Detection means available weld pipe either way hydrostatic testing, ultrasonic testing, eddy current testing in. 　　Hydrostatic test is the most common, most direct and most reliable way of weld line inspection, is in a variety of hydraulic test machine. When the pressure test, the first pass low-pressure water, filled the entire root steel side by side to make the air, and then to test pressure prescribed way through the booster and stabilize the prescribed time, at the test pressure, when no steel welds and around wet, spray, water leakage or permanent deformation, is considered qualified. 　　Pipe pressure test procedure: 　　(1...

　　Thermal protection measures for steel pipes : 　 　Quenching distortion or cracking 　　Strictly enforce the correct heat treatment, heating temperature, check the temperature control, ensuring consistent uniform temperature, as well as other measures taken to preheat; choose a reasonable cooling medium and the quenching method using pre-cooled or fractionated or isothermal hardening ; Choose qualified high-pressure seamless tube as organization and composition; adequate and timely tempering; improve design, reduce stress concentration, or the poor parts of the cross-section to be protected. 　　Insufficient hardness 　　Strictly enforce the requirements of heat treatment process to prevent subcritical quenching; a reasonable choice of the cooling medium and cooling methods, or choose to meet the requirements of the raw materials used in salt bath furnace or protective atmosphere furnace heating parts, to avoid changing the chemical composition of the surface. 　 　Uneven hardness ...

　　ASTM A335 Pipe (ASME S/A335, Chorme-Moly) is a seamless ferritic Alloy-Steel Pipe for high temperature service. Pipe ordered to this specification shall be suitable for bending, flanging (vanstoning), and similar forming operations, and for fusion welding. Sometimes referred to as “P Grade”, chome moly pipe is popular in P-Grades P5, P9, P11, P22, and P91. The most common use of grades P11, P22, and P91 is in the power industry and petro-chemical plants, Grades P5 and P9 are commonly used in refineries. 　　ASTM A335 P9 Alloy Steel Pipes is the part of ASTM A335, Alloy steel, Alloy steel pipe, ASTM A335, ASTM A335 p9, Steel pipe 　　The pipe shall be suitable for bending, flanging, and similar forming operations, and for fusion welding. The steel material shall conform to chemical composition, tensile property, and hardness requirements. 　　Each length of pipe shall be subjected to the hydrostatic test. Also, each pipe shall be examined by a non-destructive examination method in acc...

　　What is the purpose of welding steel pipe? 　　1.Low pressure fluid transfer galvanized welded pipe (GB/t3091-1993), also known as galvanized welded pipe, commonly known as white pipe. Is used for conveying water, gas, air, oil and steam heating, warm water, etc. are generally lower pressure fluid or other uses hot-dip galvanized welded's (furnace brazed or welded) steel pipe. Pipe wall thickness then divided into ordinary galvanized steel and thicker galvanized steel; take over the side into the form of threaded galvanized steel and non-threaded galvanized steel band. Pipe specifications with nominal diameter (mm), said nominal diameter is the diameter of the approximation. Traditionally commonly expressed in inches, such as 11/2 and so on. 　　2.Welded steel pipe is used for transporting water, gas, air, oil and heating steam and other general low pressure fluid and other uses. Then divided into ordinary steel pipe wall thickness and thicker steel; take over the side into the f...

　　The most effective way to identify the screw thread of the screw is to use the joint foot, which is a special tapered internal caliper that marks the outer diameter and the expansion of the female thread root. It is easy to use, intuitive and accurate.You can also directly use the long leg calipers combine steel ruler to measure the external thread root diameter, length, thread expanding cone threaded aperture control specification query. 　　Due to defects in the weld parallel, so the spiral steel pipe, its weld defects; oblique defects. During use, the main stress direction of the steel pipe, the equivalent defect length of the pipe axis direction than straight seam pipe small; secondly, because the pipeline are rolled steel plate, impact toughness greater anisotropy, along the rolling direction CVN impact values ??than perpendicular to the rolling direction CVN value three times higher. Straight seam pipe suffered precisely perpendicular to the principal stress pipe impact resista...

　　ERW steel pipe must be prepared before welding, including beveling of weldments, surface cleaning of parts to be welded, and drying of flux. Bevel processing should ensure that there are no defects such as incomplete penetration at the root of the weld, and the amount of filler metal should be reduced as much as possible to meet the requirements, so as to save costs. Commonly used bevels are V-shaped, Y-shaped, X-shaped, double-Y and double-U-shaped. When the plate thickness is the same, the double-sided groove is smaller than the single-face groove, the U-shaped groove consumes less filler metal than the V-shaped groove, and the welding deformation is small, especially as the plate thickness increases, these advantages are more prominent, for larger steel pipe with thick wall can be opened with X or double U-shaped groove. 　　The cleaning of the parts to be welded is mainly to remove surface rust, scale, oil and moisture, and prevent defects such as pores and slag inclusions. Gener...

　　The bearing capacity of a lsaw steel pipe is related to two points. One point is the mechanical properties of the steel, which is related to the commonly stated yield point, tensile strength, elongation and impact toughness. The other point is related to the geometrical characteristics of the section. Generally, a circular straight welded pipe has the strongest resistance to local buckling, and thus it is the best member to withstand radial internal pressure and radial external pressure. 　　Under the same steel number, equal area and the same supporting conditions, the rectangular slanted steel pipe has strong eccentric compression bearing capacity, and the circular and square steel tubes have the strongest compressive bearing capacity, but the square and rectangular lsaw steel pipes are subject to the ability of the nip to resist local buckling is not as good as that of a circular steel tube. Compared with the lsaw steel pipe, the seamless steel pipe has a complicated production pr...

　　We often discuss the BS standard of steel pipe.Today, we will show you the specific meaning of EN10216 standard among ERW steel pipe or seamless and other steel pipes. 　　This kind of steel pipe can be made into non alloy steel pipes and seamless steel pipes for pressure purpose. All of these steel pipes can be used among pressure vessels, boilers and heat exchange. Here are some detailed data for it: 　　EN 10216-1: Non-alloy steel pipes with specified room temperature properties; 　　EN 10216-2: Non alloy and alloy steel pipes with specified elevated temperature properties; 　　EN 10216-3: Alloy fine grain steel pipes; 　　EN 10216-4: Non-alloy and alloy steel pipes with specified low temperature properties; 　　EN 10216-5: Stainless steel pipes. 　　 http://www.xysteelpipe.com/info/Exact-meaning-for-EN10216-standard-among-steel-pipe-1195-1.htm

　　Check and check the complete data of the stainless steel pipe. 　　We know that stainless steel seamless tube have high quality requirements for seamless pipes under high temperature and high pressure. 　　Cracks in the pipe, due to improper machining process during production, may lead to improper rolling or drawing die setting, folding, warping, scratching or strain, surface and internal defects, etc. In order to ensure the quality of seamless steel tubes, according to the relevant technical standards of the products, the seamless steel pipe production line requires surface and internal nondestructive testing. Commonly used eddy current testing and magnetic flux leakage detection technology. 　　Eddy current detection is an electromagnetic induction based on a nondestructive testing method. It drives a sinusoidal excitation probe coil, when the probe is close to the seamless surface, the induction current produced by the induction electromotive force, that is, the eddy in the alter...

　　Crevice corrosion is a form of local corrosion cracks when surface passivation layer of surface sediment or shielding area is destroyed. 　　There are cracks in the welding process or design of the stainless steel pipe joint at the other joint. In effective corrosion sites, the crack must be wide enough to allow corrosive electrolyte to enter the stagnant zone. The width of the corrosion crack is several meters wide, but it is not absolute. The critical crack size leads to corrosion. 　　In particular, the negative chlorine ions have high activity. Therefore, if there is an external body solution of the crack, the metal ions with positive charge are easily attracted to the narrow cracks. The cracks (usually chromium) in the metal chloride formed to form hydrochloric acid, reduce the pH value to passivate the pH value and passivate. The cracks in the membrane were destroyed and further pitted. Events should be passivated, corrosion will be fast and self - sustaining, especially when t...

　　Hot rolled is relative to the cold-rolled, cold rolling is below the recrystallization temperature of the rolling, and hot rolled is carried out at above the recrystallization temperature of the rolling. 　　 Advantages : 　　Hot rollded seamless steel pipe can damage the cast microstructure of the steel ingot, refinement of the crystal grains of the steel, and eliminate the defects of the microstructure, so that the the steel organization compacting, improve the mechanical properties. This improvement is reflected in the rolling direction, so that the steel is no longer to a certain extent isotropic; pouring the formation of bubbles, cracks, and osteoporosis, under high temperature and pressure can also be welded together. 　 　Disadvantages: 　　1. After the hot rolling, the nonmetallic inclusions in the interior of a steel (mainly sulfides and oxides, as well as the silicate) was pressed into a sheet, stratified (laminated) phenomenon appears. The layering of the steel in the thic...

　　Seamless steel pipe is rolled metal blank, seamless steel pipe through the die drawing into section reduced length increased processing method, are mostly used for cold working, and the metal is put in the sealed container, pressure is applied to one end, whereby the metal extruder with a same shape and size of the finished die hole in a predetermined processing method, which is extruded. In this way, when the production of non-ferrous steel sheet multi. 　　In the case of smelting strict control, there may be delamination defects in seamless steel pipe, which controls the pipe to improve the plasticity and toughness, and improve the cleanliness of the steel, while reducing the harmful impurities. To reduce osteoporosis center segregation and center on the need to increase the proportion of equiaxed slab, only to take reasonable cooling system to be able to avoid cracks inside the slab, billet or rolling off the assembly line for coarse blanks to take the slow cooling process, reduci...

　　The solution temperature is mainly determined by chemical composition. In general, the solution temperature should increase for those containing many kinds of alloy elements or with high alloy. Especially for those that contains high steel, like manganese, molybdenum, nickel, silicon. Only by increasing the solution temperature can we dissolve and soften them. But for stabilized steels such as 321 stainless steel pipe, when the solution temperature is high, the carbide of the stabilizing elements are fully dissolved in the austenite and precipitate in the grain boundary with the form of Cr23C6 after cooling. That can cause intergranular corrosion. We often adopt the lowest solution temperature for carbide(Tic and NbC) of the stabilizing elements which can't be dissolved or treated by solid solution. 　　For seamless stainless steel pipe, the three elements of the solution treatment are temperature, holding time and cooling rate. What is the role of solution treatment of seamless ...