ERW Steel Pipe

　　Pipe straightness is a measure of the amount of bending, pipe diameter deviation, roundness, etc. of the pipe. 　　In the production process, the steel pipe will cause different degrees of curve in the longitudinal direction (that is, the length direction) of the steel pipe body. However, the degree of curve of some steel pipe products can be visually seen by the naked eye, and the steel pipe is not a qualified product. As long as it is a regular manufacturer, such products are absolutely not allowed to leave the factory, and some need special equipment to measure their straightness. 　　The pipe straightness measurement method mainly introduces two kinds, one is the inner hole straightness measurement method, and the other is the online straightness measurement. 　　The inner hole straightness measurement is measured by laser collimation. The basic principle of the straightness detecting device is to use the laser beam as a linear reference object to detect the bending offset and be...

　　Square tube is generally used for structural and maintenance purposes, such as the construction of buildings, railings and signposts. It is measured by its outer dimensions and its thickness, taking the outer walls (which are the same size) and then the wall thickness. 　　The square tube allows easier welding of several tubes, joining their ends. It is also easier to store stacked. 　　The most used materials to manufacture this type of tube are aluminum and steel, although iron is also widely used for its tenacity in structures where the risk of rust is not relevant. They are available in many storage lengths, which normally range from 60 cm to 7 meters, although they can be made to measure. 　　Being an alloy (iron and coal) has many interesting properties. It is a material heavier than aluminum (three times more), so it is especially valued for use in heavy structures and / or that require resistance to corrosion and extreme temperatures, such as the construction of both houses ...

　　According to different forming methods, seamless tube can be divided into two types: extruded and cold drawn. 　　1. Hot rolling (extrusion): round billet → heating → perforation → three-roll cross-rolling, continuous rolling or extrusion → pipe removal → sizing (or reducing diameter) → cooling → straightening → hydraulic test (or flaw detection) → marking → the raw material for the seamless tube in the warehouse is a round tube blank. The round tube blank is cut into a blank of about 1 m in length by a cutting machine, and sent to the furnace for heating through a conveyor belt. The billet is fed into a furnace and heated to a temperature of approximately 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is a key issue. After the round billet is released, it is subjected to a through-hole punching machine. 　　The more common perforating machine is a conical roller punching machine. This perforating machine has high production efficiency, good pro...

　　Seamless black steel pipe is made of seamless steel pipe that has not been galvanized. Its name comes from the scaly, dark-colored iron oxide coating on its surface. It's used in applications that don't require galvanized steel. 　　The purpose of seamless black steel pipe is to carry propane or natural gas into residential homes and commercial buildings. So that pipes is manufactured without a seam, making it a better pipe to carry gas. Seamless black steel pipe's strength makes it ideal for transporting water and gas in rural and urban areas and for conduits that protect electrical wiring and for delivering high pressure steam and air. The oil and petroleum industries use black steel pipe for moving large quantities of oil through remote areas. This is beneficial, since black steel pipe requires very little maintenance. Other uses for black steel pipes include gas distribution inside and outside homes, water wells and sewage systems. Black steel pipes are never used fo...

　　1. The welded pipe is made of steel plate welded by high-frequency electric resistance welded pipe (ERW welded pipe), straight seam electric welded pipe (LSAW), spiral welded pipe.In electrical engineering, it is indicated by "SC". It can be used as a water gas pipe or a threading pipe, which is relatively thick. 　　2. The line pipe is also the wire tube, relatively thin, with the "T", can only be used for threading. 　　3. The ERW tube is a “high-frequency resistance welded steel pipe”. It is different from the ordinary welded pipe welding process. The weld is made of the base material of the steel strip body, and the mechanical strength is better than that of the general welded pipe. 　　ERW straight seam steel pipe means electric resistance welding. Resistance welding has the characteristics of high production efficiency, low cost, material saving and easy automation. Therefore, it is widely used in various industrial sectors such as aviation, aerospace, energ...

　　The electric resistance welding time is short and the process is not visible, so during the actual welding process, there will be joint quality of instability caused by the instantaneous voltage fluctuations, current shunt, electrode wear and other factors. Nowadays, the application of resistance welding technology has widespread, so the quality control is extremely important. Over the years, many scholars have proposed various resistance welding quality control methods, below is several mature control method we can apply. 　　1. Constant Current Control 　　This method is applied by comparing the detected welding current with the given value, and regulating the firing angle by using its bias swithcing device so as to adjusting the constant current equal to the given value. The key point is how to capture the constant current control current signal. At present, a current collected by the collecting main core coil sensor detects the welding current from the secondary circuit, which di...

　　The biggest difference thin-wall and thick-wall welded steel pipe is the wall thickness. When the ratio of pipe diameter and wall thickness is less than 20, we called this type of carbon steel pipe as thick-walled welded steel pipe. The thin-wall welded steel pipe is applied for pipeline transmission. However, the thick-wall straight seam pipe is mainly used for petroleum geology drilling pipe, petrochemical cracking tube, boiler tube and pipe for automotive bearings, tractors, aviation etc. In general, it is used in multiple parts of the hollow billet and important channel for bearing large pressure. 　　With the increasing requirement for oil and gas pipeline pressure, the application of steel pipe towards to high grade, large-diameter and thick-wall steel pipe. In order to increase the welding quality and production efficiency, limit the weld slag is significant. During the production of thick-wall straight seam welded pipe, we need to reduce the propability of fusion weld toe cl...

　　1. Test Process 　　Sampling from the defective LSAW steel pipe , and then confirm the location of the defect in the weld seam by manual ultrasonic flaw detector, then processing the weld cross defect section by the method of machining by grinding, polishing, etching after a metallurgical sample. Through the metallurgical test, we can notice the location and quantity of weld slag. 　　2. Cause Analysis 　　Theoretically, submerged arc welding seam slag is produced mainly due to the following three points: 　　A. raw materials inclusions (including base metal, wire, flux) 　　B. the multilayer welding interlayer is not clean up 　　C. improper selection of welding parameters is not conductive to slag floats. 　　According LSAW pipe production characteristics can be excluded when the layer of multilayer welding clean up is not clean leaving weld slag produced for this reason.After the raw material for many inclusions leaving produce weld slag, weld inspection before taking the base mat...

　　High frequency straight seam welded steel pipe also know as straight seam resistance welding pipe. The outside diameter is small, usually is under DN 600. For the outside diameter is larger than DN 600, the production process will use double sided submerged arc welding process. The high frequency straight seam welded steel pipe is mainly used in water engineering, petrochemical industry, chemical industry, power industry, agriculture irrigation and urban construction. For the transportation of liquids, the pipe can be applied for water supply, drainage. For gas transportation, the pipe can be used for transmission gas, steam, liquefied petroleum gas. For structural purposes, the pipe can be used as piling pipe fro bridges, piers, roads, buildings and other structures. 　　The characteristics for high frequency straight seam welded steel pipe is below: 　　1. the welding speed is large. 　　2. the welding area is small. 　　3. clean up is not necessary after welding 　　4. the weldin...

　　The production and processing of large diameter tubes can be carried out according to different procedures, depending on the final destination of the products: in particular, round and square tubes can be created by welding, by hot rolling or without welding. The welding, in turn, can be of different types: electric resistance (it is indicated with the initials ERW), in submerged arc (it is indicated with the abbreviation SAW), in a helical submerged arc or longitudinal . 　　We deals with the production of large diameter square section and circular section tubes. They can be used in numerous fields, from the agricultural sector to the energy sector, from the pharmaceutical sector to the chemical sector, and therefore can be used in a wide variety of contexts. Also of considerable importance: large steel pipes, in fact, represent a fundamental component of nuclear plants, mining companies and refineries. 　　Following production, large-diameter pipes can be subjected to processing or...

　　At present, large-diameter thick-walled steel pipes, large-diameter thick-walled seamless steel pipes, small-diameter thick-walled seamless steel pipes, special thick-walled steel pipes, large-diameter coiled pipes, thick-walled coiled pipes and other series of thick-walled steel pipes have been formed. It replaces the same standard imported steel pipe and is applied to hydraulic system piping. 　　Thick-walled steel pipes, which are steel pipes with a ratio of outer diameter to wall thickness of less than 20, are called thick-walled steel pipes. It is mainly used as petroleum geological drilling pipe, cracking pipe for petrochemical industry, boiler pipe, bearing pipe, and high-precision structural pipe for automobile, tractor and aviation. 　　The biggest difference between thick-walled steel pipe and thin-walled steel pipe is the thickness of the steel pipe wall. Generally speaking, thin-walled steel pipes are cold drawing technology, thick-walled steel pipes and thick-walled stee...

　　1. The length of the spiral steel pipe can be not tied. 　　2. For both ends of the spiral steel pipe, if there is a thread buckle, it should be protected by a thread protector. Apply lubricant or rust inhibitor to the thread. Both ends of the spiral steel pipe are broken, and the nozzle protector can be added at both ends according to requirements. 　　3. Spiral steel pipe packaging should be able to avoid looseness and damage during normal handling, transportation and storage. 　　4. If the customer requests that the spiral steel pipe cannot be damaged by bumps or the like on the outer surface, it may be considered to adopt a protection device between the spiral steel pipes. The protective device can use rubber, straw, fiber cloth, plastic, cap, and the like. 　　5, Thin-walled spiral steel pipe due to thick wall can be used to support the inside of the pipe or the protection of the outer frame. The material of the bracket and the outer frame is made of steel material which is con...

　　The large-diameter seamless steel pipe adopts unique technology. Its finished appearance looks high precision, and the quality of the inner and outer walls is smooth and the image is good. Generally, the preservation process of the factory is strictly controlled, not casually. A small warehouse can be completed. If the storage is not good, it will greatly reduce the selling phase, and it will also reduce the energy and effort that the manufacturer spends on it. Every step is going through an extremely delicate process. It can be done, and in general, they will be stored in a warehouse at a certain temperature. 　　With such a good storage, the sales of large-diameter seamless steel pipes are better, which is also the ingenuity that researchers have taken for him. It is finished by special treatment. After the product is formed, it can be delivered directly without deep processing, eliminating the tedious steps of deep processing again. Because of special treatment, there is no need ...

　　Seamless square steel pipe classification 　　1.Process classification 　　 Seamless square steel pipe according to the production process: hot-rolled seamless square tube, cold drawn seamless square tube, extruded seamless square tube, welded square tube. 　　2. Among them, the welded square tube is further divided into: (a) according to the process points - arc welded square tube, resistance welded square tube (high frequency, low frequency), gas welded square tube, furnace welded square tube;  (b) according to the weld ——Stitched square tube and spiral welded square tube. 　　3. Material classification 　　Seamless square steel pipe according to material: ordinary carbon steel square tube, low alloy square tube. The carbon steel is divided into: Q195, Q215, Q235, SS400, 20# steel, 45# steel, etc.; low alloy steel is divided into Q345, 16Mn, Q390, ST52-3 and so on. 　　4. Production standard classification 　　Seamless square steel pipe according to production standards: natio...

　　Type of stainless steel tube: 　　The rolling method is divided into hot rolling, hot extrusion and cold drawing (rolling) stainless steel tubes. 　　According to the stainless steel metallographic structure, it is divided into semi-ferritic semi-Martensitic stainless steel pipes, martensitic stainless steel pipes, austenitic stainless steel pipes, austenitic-ferritic iron stainless steel pipes. 　　Stainless steel tube specifications and appearance quality: 　　A. According to GB14975-94 "stainless steel seamless steel pipe", the normal length of steel pipe (indefinite) hot-rolled steel pipe is 1.5~10m, and the hot-extruded steel pipe is equal to or greater than 1m. Cold drawn (rolled) steel pipe wall thickness of 0.5 ~ 1.0mm, 1.0 ~ 7m; wall thickness 　　greater than 1.0mm, 1.5 ~ 8m. 　　B. There are 45 kinds of hot-rolled (hot-extruded) steel pipes with a diameter of 54-480 mm; a total of 36 kinds of wall thicknesses of 4.5-45 mm. There are 65 kinds of cold drawn (rolled...