The ERW steel pipe Resistance is high frequency straight seam welded pipe, the English Electric hold Welding, abbreviation abbreviation for ERW, used for transporting oil, gas and vapor liquid object, can meet the requirements of high and low pressure various, currently in the field of conveying pipe in the world occupies a pivotal position.
1, welded pipe refers to the common "submerged arc welding steel pipe," marked "SC" electrical engineering, can be used as water gas pipe can also make the threading pipe, thick.
2, line pipe, wire and tube, thin, with a "T", said can only do threading works.
3, ERW pipe is "high-frequency resistance welding steel tube", unlike ordinary welded pipe welding process, welding seam is composed of steel belt ontology of parent metal melting and mechanical strength than the general welding control.
ERW said resistance welding, resistance welding with high production efficiency, low cost, save material, easy automation, etc, therefore widely used in aviation, aerospace, energy, electronics, automobile, light industry and so on various industry sectors, is one of the important welding process.
ERW steel pipe and seamless steel tube the biggest difference lies in the ERW a weld, this also is the key of the ERW steel tube quality.Modernization of ERW steel pipe production technology and equipment, due to the international, especially the years of unremitting efforts, such as the United States made the seamless ERW steel pipe have satisfactory solution.Someone of ERW steel pipe seamless tumble into geometric seamless and physical seamless.Seamlessly geometry is inside and outside the burr removal of ERW steel pipe.Due within the burr removal system's structure and tools of continuous improvement and improvement of the steel pipe within the burr removal of large and medium caliber have had a better processing.Within the burr can be controlled in 0.2 mm ~ o. 5 mm or so.Physical seamlessly refers to the inside of the weld microstructure and the difference between the parent metal and led to the decrease of the mechanical properties of weld area, some measures are needed to make it uniform and consistent.ERW steel pipe, high frequency welding thermal process caused the tube billet temperature gradient near the edge, and formed the melting zone, half melting zone, overheating organization, is fire area, incomplete area is fire area, back to the fire area and other features.The overheated zone tissue due to welding temperature above 1000 ℃, the austenitic grain size grew up sharply, under the condition of cooling can form the coarse grain of hard and brittle phase, furthermore the existence of the temperature gradient can produce welding stress.Thus formed the mechanical properties of the weld area is lower than the parent metal, physical seamlessly is weld local conventional heat treatment process by using medium frequency induction heating device is the area of the welding heat in the AC3 (927 ℃), and then to 60 m length and speed in air cooling process of 20 m/min, water-cooled again when necessary.This method is used to eliminate stress, soften and refine the organization, improving the purpose of the welding heat affected zone comprehensive mechanical performance.At present, the world's advanced ERW unit has been widely used this method to deal with weld, has obtained better effect.High grade ERW steel pipe not only unable to recognize weld, and the welding seam coefficient reaches 1, implements the weld area and matching of the parent metal.
ERW steel pipe by using hot rolled plate as raw material, wall thickness can be controlled around + / - 0.2 mm, tube two terminal according to the APl standard or standard, GB/T9711.1 repair end groove, specified length of delivery, etc.In recent years, the natural gas pipe network engineering and gas companies has been widely used in ERW steel tube as the main pole of city pipe network.