• Surface treatment of high frequency welded steel pipe

    With the sustained economic development in our country, the government has made great efforts to develop the energy industry and long-distance oil and gas pipelines are important ways to ensure energy supply. During the anticorrosive construction of pipeline (gas) pipeline, the pipe surface treatment is the key factor that determines the anti-corrosion service life of pipelines First, it is a prerequisite for the coating and pipe can be firmly combined. The research institutes have verified that the life of the coating depends on the type of coating, coating quality and construction environment and other factors, the impact of the surface treatment of steel pipe coating life expectancy of about 50%, therefore, it should be strictly in accordance with the coating standard. Steel pipe surface requirements, and continue to explore and summarize the continuous improvement of steel pipe surface treatment methods.  1, Cleaning The use of solvent, emulsion cleaning steel surface, in order to achieve the removal of oil, grease, dust, lubricants and similar organic matter, but it can not remove the rust on the steel surface, scale, welding and so on, and therefore only as an adjunct to preservative production. 2, Tool rust The main use of wire brush and other tools on the polished steel surface, you can remove the loose or tilt the oxide skin, rust, welding slag and so on. Manual tool rust can reach Sa2 level, power tool rust can reach Sa3 level, if the steel surface attached to the solid oxide scale, tool rust effect is not satisfactory, reaching the depth of anchor embossed construction requirements. 3, Pickling Generally use chemical and electrolytic pickling two ways to do, pipe corrosion only chemical pickling, you can remove the scale, rust, the old coating, and sometimes can be used as a reprocessing sandblasting rust. Although chemical cleaning can make the surface to a certain degree of cleanliness and roughness, its anchor pattern shallow, and easy to cause environmental pollution.  4, Spray (throwing) shot rust Spraying (throwing) shot rust is driven by high-power motor spray (throwing) shoot high-speed rotation of the blade, so grit, steel balls, wire segments, minerals and other abrasive centrifugal force under the action of spraying (throwing), not only can completely remove the rust, oxides and dirt, but also in the steel under the impact of abrasive and friction, but also to achieve the required uniform roughness. Spraying (throwing) shot rust, not only can expand the physical adsorption of the pipe surface, but also can enhance the coating and pipe surface mechanical adhesion. Therefore, spray (throwing) throw rust is ideal anti-corrosion pipe rust way. In general, shot peening (sand) rust is mainly used for pipe surface treatment, shot blasting (sand) rust is mainly used for pipe surface treatment.
  • Storage of welded pipe

    Storage of welded pipe : 1, Whether naked pipe or anti-corrosion pipe, for a long time to store, from the beginning of storage should be used opaque cover protection, to avoid corrosion of pipe and corrosion coating aging, Alice edge and so on. 2, Covering should be strong and durable, to prevent prolonged sun and rain rot and leakage. 3, The pipe cover should ensure that the surface of the pipe ventilation, to avoid the difficult evaporation of water vapor in the surface pool. 4, Pipe storage should be supported, and a certain distance from the ground to ensure that the pipe ventilation. 5, Welded pipe stacking storage, should remove the tube end protector, to avoid moisture in the tube end protector and pipe contact surface collection and difficult to volatilize. 6, Welded pipe storage should pay attention to the pile of welded pipe, to avoid too much layer caused by the pipe end of the local stress, so that the pipe has a radial plastic deformation and coating damage. 7, Welded pipe storage to avoid contact with contaminants oil, copper and so on. 8, To develop long-term welded pipe system documents, and in accordance with the system implementation.
  • Heat treatment of quenched and tempered steel

    Pre-heat treatment In order to eliminate and improve the organizational defects and internal stresses of the former process (casting, forging, rolling and drawing) and to make the organizational and performance preparation for the later process (quenching, cutting and drawing), annealing or normalizing Process is pre-heat treatment. On the pre-quenched and tempered steel prior to cutting heat treatment, pearlite steel can be carried out in the Ac3 above a normalizing or annealing; martensitic steel with high content of alloying elements are first Ac3 above an air-cooled quenching, and then Ac1 The following high-temperature tempering, so that the formation of tempered sorbite.  The final heat treatment Quenched and tempered steel general heating temperature above Ac3 30 ~ 50 ℃, quenching martensitic organization. Tempering sorbite should be obtained by tempering at high temperature after quenching. Tempered tempering temperature according to the performance requirements of the parts, generally take between 500 ~ 600 ℃, depending on the specific scope of the chemical composition of steel and parts of the technical conditions may be. Because alloying elements will slow down the decomposition of martensite, carbide precipitation and aggregation and the transformation of residual austenite and other processes, the tempering temperature will shift to higher.
  • Welded pipe production

    Welded pipe production methods are mainly straight seam welded pipe and spiral welded pipe. At present, there are about 1600-1800 straight ERW welded joints, 5 sets of straight seam large diameter submerged arc welded pipe units and 90 sets of spiral welded pipe units with an annual production capacity of 9 million tons or more. Welded pipe production in both non-ferrous and black production have a faster development. Small and medium straight seam welded pipe are basically produced by roll continuous molding machine, the unit has the advantages of simple equipment, less investment, high output, low cost, good mechanical property, high precision, uniform wall thickness, smooth surface and good weld quality features. High-frequency welded pipe machine currently produces φ5 ~ 660 × 0.5 ~ 15mm water gas pipelines, boiler tubes, tubing, oil drilling pipe and machinery industry tubes. When using roll forming method, the product specifications can be expanded to φ400 ~ 1220 × 6.4 ~ 22.2mm. UOE method is the main method of producing large diameter straight seam welded pipe, which can produce φ406 ~ 1625 × 6.0 ~ 32mm, up to 18m pipe. The United States first applied this method to production in 1951. With the development of the oil and gas industry, the demand for large-caliber high-strength pipe increased sharply, which promoted the development of the production law. The world's ownership is more than 30 sets. In recent years, rapid development, the new 4 sets of UOE. Spiral welded pipe appeared in 1888. Currently the United States, West Germany has produced a diameter of 3m above the thickness of 25.4 mm spiral welded pipe. Compared with UOE, spiral welding can use the same wide coil production of different diameter pipe; inside and outside the weld is spiral, with the role of enhancing the rigidity of the pipe; tube straightness, without setting the straightening machine, the outer diameter Ovality is small, but the outside diameter deviation is greater than the UOE method; the production process is easy to mechanization, automation and continuity; equipment appearance is small, less investment.
  • Steel surface treatment

    First of all equipment, valves, flanges and pipelines paint removal derusting, sand blasting process, completely remove the rust layer. After the derusting with clean compressed air purge the surface, after passing the inspection, in no more than 8 hours for spraying treatment. After cleaning the quality of steel surface rust should be achieved, "pre-painted steel surface pretreatment specification" (SY / T0407-97), Sa3 level standards. Specific criteria are as follows: sandblasting rust completely remove the scale rust, the old coating and other dirt. After cleaning, there is no visible grease, grease, lime soil, scale, old coating on the steel surface, and the metal surface shows uniform metallic luster and roughness.
< 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ... 67 >