LSAW Steel Pipe

　　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 alte...

　　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 ...

　　The advantages of this ERW steel pipe processing technology are that there is a heat treatment process after welding to eliminate the residual stress in the weld and heat affected areas, to refine the grain, and to make the heat affected zone of the weld small, and the heating speed is fast, thus greatly improving the welding speed and welding quality, and can be used as a blank without pickling, shot peening and trimming. At the same time, it can weld alloy steel, high alloy steel and non-ferrous metal pipe, greatly reducing unit power consumption. A set of welding equipment can be used to produce each. 　　The advantages of this ERW steel tube processing technology are that there is a heat treatment process after welding to eliminate the residual stress in the weld and heat affected areas, to refine the grain, and to make the heat affected zone of the weld small, and the heating speed is fast, thus greatly improving the welding speed and welding quality, and can be used as a blank...

　　The polishing method of seamless steel pipe is as follows: 　　 1.mechanical polishing 　　The 1. advantage is that the parts are smooth and the brightness is high after processing. The disadvantage is that the labor intensity is too big, cause serious pollution, can not process complex parts, the luster can not be consistent, the heat preservation time is not long, the mechanical polishing is suitable for the processing simple parts, and the small and medium parts. 　 　2. chemical polishing 　　A little bit is investment equipment, complex parts can be polished, fast, efficient, good corrosion resistance, the drawback is poor lighting, ventilation equipment, heating difficulties. It is applicable to small complex parts and small parts that do not require high brightness. 　　 3. electrochemical polishing 　　The advantages are long mirror gloss, stable process, low cost and poor corrosion resistance. The disadvantage is that the equipment must be invested at a large time, the compl...

　　A spiral welded steel pipe is a steel pipe which is welded and formed by a steel strip or a steel plate to be deformed into a circular shape or a square shape and has a joint on the surface. According to different welding methods, it can be divided into arc welded pipe, high frequency or low frequency electric resistance welded pipe, gas welded pipe, furnace welded pipe, Bondi pipe and so on. According to the shape of the weld, it can be divided into a straight welded pipe and a spiral welded pipe. Electric welded steel pipes are used in oil drilling and machinery manufacturing. The furnace welded pipe can be used as a water gas pipe, etc., the large diameter straight seam welded pipe is used for high pressure oil and gas transportation, etc.; the spiral welded pipe is used for oil and gas transportation, pipe piles, piers and the like. 　　Welded steel pipes have lower cost and higher production efficiency than seamless steel pipes. Straight seam welded pipe has simple production pr...

　　The seamless expansion of the seamless steel tube is divided into an overall thermal expansion treatment, a surface thermal expansion treatment, and a chemical heat treatment. The seamless expansion of the seamless steel pipe is generally treated by integral thermal expansion. Generally, they are subjected to basic processes such as heating, heat preservation, and cooling, and defects may occur in these processes. 　　Heat treatment defects of seamless steel tubes mainly include unqualified structural properties of steel pipes, excessive size and surface cracks, scratches, severe oxidation, decarburization, overheating, and over-burning. 　　Features of thermal expansion processing of seamless steel tubes: 　　The first process is heating: one is heating below the critical point Ac1 or Ac3; the other is heating above the critical point Ac1 or Ac3. The first is mainly to stabilize the structure of the seamless steel pipe and to eliminate the residual stress of the seamless steel pipe,...

　　Common processing methods for steel pipe: 　　1. Forging method: use forging machine extend to the end or part of the tube, to reduce the outer diameter, commonly used forging machine are rotary, connecting rod, roller type. 　　2. Stamping method: use a tapered core on the punch to extend the pipe end to the desired size and shape. 　　3. Roller method: place the core in the tube,rolling the outer with a roller, used for the round edge processing. 　　4. Rolling method: generally it do not have mandrel, suitable for thick-walled tube with the round edge inside. 　　5. Bending method: There are three common methods: extension method, stamping method, roller method. There are three-four rollers, two fixed roller, a adjustment roller, adjust fixed roller distance, then finished pipe is bent. 　　6. Blowing method: one is placed in the tube rubber, the top with a punch compression, protruding shape the tube; another method is the hydraulic bulging shape, fill liquid in the middle of the...