LSAW Steel Pipe

　　The causes of large diameter spiral pipe wrong side: large diameter spiral steel pipe production, the wrong side have occurred with many of its factors. In the production practice, often the wrong side of the ultra-poor leaving dry pipe downgrade. Therefore analyze the causes and prevention of large diameter spiral pipe produced the wrong side is necessary. 　　1, the strip camber is caused by the wrong side of the main factors pipe. In forming the spiral welded pipe, steel strip camber angle will constantly change shape, leading to changes in the weld gap, resulting in open seams, wrong side or even take sides. Seriously affecting the quality of steel, so the observation camber steel strip coil-after by controlling the vertical roll can be cut to make the disc as well as the continuous removal of part of camber angle control and corrective shaping is to reduce the camber of the strip in the production process effective way to produce the wrong side. 　　2, due to the poor without t...

　　 Spiral pipe factory should be done before the mechanical performance test and flattening test, and flaring test, and to achieve the standard requirements. Straight seam steel quality inspection method is as follows: 　　1, From the face of it, that is visual inspection. Visual inspection of welded joints is a simple procedure but widely used test method is an important part of product testing, the main defects and deviations are found on the surface of the weld size. Usually by the naked eye, with the standard model, gauge and test tools such as a magnifying glass. If the weld surface defects, weld defects there may be internal. 　　2, Physical test methods: physical test method is to use some physical phenomena assay or test method. Or within the workpiece material defect inspection, and are generally used NDT methods. NDT ultrasonic flaw detection, radiation detection, penetration testing, magnetic testing and so on. 　　3, Pressure vessels strength test: pressure vessels, in add...

　　Breakage of spiral pipe according to the material after the destruction of anti-corrosion steel case and metal material is substantially the same divided into three types, namely: ① cleavage fracture, ② tie troglobites anti-fracture, ③ slip surface separation fracture. 　　Cleavage fracture along a section strictly crystal - product surface separating the planes called cleavage plane. When the fracture along the crystal plane, the theoretical minimum breaking strength. Decision cleavage plane of factors specific surface energy y, the surface of the crystal plane spacing mountains and modulus of elasticity along the normal direction. Cleavage fracture with almost no plastic deformation, is a brittle fracture occurs in the body-centered cubic, hexagonal close-packed gold center. Fcc metals is generally not cleavage fracture occurs. The nature of the genus L ductile material gold sessions, shear fracture is the main fracture mechanism. Such as anti-corrosion steel alloy second phase pa...

　　 Spiral pipe insulation method from the start of a process which also suppressed as in the pipe wall plus anti-corrosion coating, can be increased loop resistance, reduce corrosion current;. External DC power supply, the steel pipe caused by the negative potential of the soil, forming a cathodic protection, the potential difference between the anode and cathode can be eliminated, stopped anode and cathode process fundamentally. anticorrosive coating rule table, cathodic protection of the rule of law. But once the anti-corrosion coating is damaged, exposed iron part will accelerate local corrosion. Therefore, anti-corrosion coating and cathodic Protection of this combination is to rid the method table, economical and effective. As stated in the United States and other countries, using the anti-corrosion coating cathodic protection must be used at the same time. 　　But for the city gas system, due to the dense network of underground pipes, cathodic protection of the external power su...

　　Currently, double-sided spiral pipe is widely used submerged arc welding technology, following the formation and characteristics of what the submerged arc welding. 　　Principle of submerged arc welding: submerged arc welding is performed by arc welding heat, and manual arc welding is different: submerged arc welding wire is bare, no paint above, submerged arc flux is indeed to be welded in advance shop Department, submerged arc welding wire extends into the flux, the arc is burning in flux. 　　SAW formation process like this: the wire in contact with the workpiece, press the start button and instantly after pressing, welding wire and workpiece energized wire Withdrawing arc ignition, welding carriage forward, under continuous wire to transport, maintain Arc burning at the solder layer, formed under the arc weld pool. In an arc around the solder melts to form a cavity. This empty and the pool continues to advance, but the pool behind the metal solidified, forming a continuous weld....

　　Spiral steel packaging should be able to avoid loose and damaged during normal handling, transport and storage. 　　If the demand side of the spiral steel packaging materials and packaging have special requirements should be specified in the contract; if not specified, packaging materials and packaging methods are available for parties to choose from. 　　Packaging materials shall comply with the relevant requirements. If there is no requirement of packaging material, it should be up to comply with the intended use, avoiding waste and environmental pollution. 　　If the customer can not have a bump spiral pipe and other damage in appearance, can be considered between the spiral steel pipe protection device. 　　Since the thin-walled spiral pipe thin walled tube can be used within or outside the tube support framework for the protection measures. Bracket and frame materials and using the same material steel spiral pipe material. 　　Spiral pipe ends such as threaded, thread protector...

　　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...

　　Spiral pipe surface quality problems mainly in the surface oxide thick, surface cracking, heavy leather surface, surface mechanical bumps and so on. Hot-rolled carbon steel pipe after completion, after, or cold-rolled steel and then heat treated, will form a layer thick and strong adhesion, high temperature oxide. The presence of oxide steel look not only poor quality, also affect the use of steel, which is the standard are not allowed. Such oxide with the general sandblasting is difficult to remove, to use pickling or mechanical polishing method to clear. 　　Mechanical bruising is the most common quality problems, arising primarily from the production, handling and transportation. Pipe bumps are formed at a structural discontinuities, use is a source of stress concentration, but also chipped sensitive. Compared with crack, mechanical defects bruised outline clear, do not involve injuries metal, so the standard allows some bumps depth exist, but in some of the more sensitive applica...

　　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 ...

　　In the screw steel tube feeding unit, the rolled strip steel is gradually rolled up to form an open circular pipe gap, the extrusion roll is reduced and adjusted, the weld gap is controlled at 1-3mm, and the weld end face is flush. 　　1. If the gap is too large, resulting in reducing the proximity effect, eddy current lack of heat, weld crystal combined indirect adverse arising from lack of fusion or cracking. 　　2. The gap is too small, causing the proximity effect increases, excessive soldering heat, cause weld Burning; weld or extruded, rolled after the formation of the pit, affecting the quality of the weld surface. 　　After the two edges of the tube is heated to welding temperature in the extrusion of squeeze rollers, spiral pipe to form a common metal grain mutual penetration, crystallization, eventually forming a strong weld. If the spiral pipe extrusion pressure is too small, the number of co-crystal formation is small, the weld metal strength is reduced by the force will...

    If it is drinking water, IPN8710 anticorrosion spiral pipe is needed for water transportation. The IPN8710 anticorrosion spiral tube is composed of waterborne aliphatic polyurethane prepolymer and epoxy resin, high quality pigment, additive and solvent. It is specially used for food, drinking water and other equipment contact, pipeline water pipe, drinking water tank surface corrosion.     The main material of spiral pipe is carbon steel and pipeline steel series x42-x70. Storage of water supply spiral pipe products on site or warehouse should be selected in a clean and clean place away from harmful gas or dust in the production plant. Remove weeds and all debris on the ground and keep the steel clean.     There are many corrosive media for water transportation and supply. There are acids, bases, salts, oxidizers and steam. The coating must be chemically inert and acid and alkali resistant. The coating has compact structure, good water permeability...

    First, the spiral pipe thermal expansion method     Bulging method     One is placed in the tube of rubber, the top with a punch compression, so that the pipe protruding forming; the other method is hydraulic bulge forming, the middle of the tube filled with liquid, the liquid pressure drum into the desired shape, the bellows Most of the production is using this method.     2 forging method     With a forging machine to be part of the end of the pipe to punch, so that the outer diameter to reduce the commonly used forging machine rotary, connecting rod, roller type.     3. Bending forming method     There are three methods are more commonly used, a method called extension method, the other method is called stamping method, the third wheel method, there are 3-4 rolls, two fixed rolls, a roll adjustment, fixed roll distance, finished tube It is curved.     4 stamping method    ...