The thick wall elbow
Thick wall elbow is mainly used in boiler pipe in the pipe system such as, thermal power plant, with the increasing of electric installation unit capacity, such as main steam steaming-water pipe design is becoming more and more thick, and many have reached more than 70 mm thick, the traditional pipe welding operation can not meet the needs of factory piping, therefore, must improve the thick-walled elbow welding process.
The thick wall elbow is connected to the pipe fitting, including a curved pipe, which is characterized by a connecting flow through the curved pipe. Thick wall elbow has reasonable structure, can make the piping stress evenly, can simplify the pipeline system, convenient operation, can save investment, can reduce the pipeline resistance, optimized pipeline arrangement, is helpful to reduce operation cost and to balance air distribution, reduce piping vibration, to ensure the safe operation of the equipment and pipeline.
In the case of P91 steel thick wall elbow, preheating and interlayer temperature tracking is done。 According to the analysis of P91 welding performance must be strictly controlled welding temperature, preheating temperature and welding layers asked before the TIG welding preheating temperature 100 ~ 150 ℃, SMAW heating to 250 ~ 250 ℃, in the whole welding process, welding interlayer temperature using infrared thermometer monitoring。 In welding, argon protection is adopted。 P91 steel due to high alloy content, poor iron water, the root is easy to burn。 Argon gas can fully protect the metal molten pool from the oxidation and improve the mechanical properties of weld and welding according to the actual production before a set of simple argon filling equipment, air chamber is formed within the pipeline, and can ensure the quality of the welding of thick-walled elbow joint。 P91 iron water is poor, so the weld of thick wall elbow is very easy to form slag。 Use the Angle to clean the machine at the scene, do not use the hammer, the chisel is used hard to hit, in order to avoid the crack。 In addition, according to the welding code, the wall thickness is greater than 70m welding and must be tested between layers。 When the weld thickness reaches 20 ~ 25mm, stop the welding and immediately heat the heat treatment。 After the RT is qualified, continuous welding is performed。
The thick wall elbow is used as the base material with high quality wear-resistant steel, which can be used in the piping system of various situations. Such as abrasive wear, corrosion wear, erosion wear, impact wear, etc.
Thick wall elbow? Features: anti-corrosion. Resistance to acid and alkali. The service life is long, the price is reasonable, the surface is smooth, the acid and alkali resistance is high temperature, the price calculation is reasonable, the appearance is beautiful, the texture performance is strong.
Thick wall elbow? Application: used for petroleum pipeline engineering, natural gas pipeline engineering, chemical plant, power plant, shipyard, pharmaceutical, dairy, beer, beverage, water conservancy etc.