Design, manufacture and process of carbon steel elbow

The design, manufacture and process of carbon steel elbow

The hardness of carbon steel elbow shall be considered during the design and manufacture of carbon steel elbow. The carbon steel elbow shall be heated to a certain temperature and kept warm for a period of time, and then cooled slowly, which is called annealing. Annealing of hot pressed elbow is a heat treatment method that heats the steel to the temperature where phase transformation or partial phase transformation occurs, and slowly cools it after heat preservation. The purpose of annealing is to eliminate the structural defects. The actual effect is to homogenize the composition of the main structure and refine the grain, improve the mechanical properties of the hot pressed elbow, and reduce the residual stress

Carbon steel elbow is a steel hot pressed or forged reducer. Its connection mode is to directly butt weld the reducer with the steel pipe. The main manufacturing standards of concentric reducer are generally GB/T12459, GB/T13401, ASME B16.9, SH3408, SH3409, HG/T21635, HG/T21631, SY/T0510. Corresponding to the concentric reducer is the eccentric reducer, which is made of carbon steel, alloy steel and stainless steel

Carbon steel elbow is widely used in petroleum, natural growth gas, chemical industry, hydropower, construction, boiler and other industries. The forming process of butt welding elbow of pipeline system is complex, and it needs to be welded according to different materials and uses, and gradually formed under determined pressure

The advantages of the forming process of carbon steel elbow are mainly shown in the following aspects:. The raw material of this reducer is special, and it does not need to add the raw material of tube blank, so it is easy to control during processing

2. It does not need pipe blank as raw material, which can save the cost of pipe making equipment and mold, and it can be deeply used for carbon steel elbow with any large diameter and relatively thin wall thickness

3. Due to the above two reasons, the manufacturing cycle can be shortened and the production cost can be reduced. Since no one-to-one equipment is required, it is especially suitable for on-site processing of carbon steel reducers

The carbon steel elbow shall first weld a polygonal polygonal annular shell or a polygonal fan-shaped shell with closed ends. After the internal pressure medium is filled, internal pressure is applied. Under the internal pressure, the cross-section gradually changes from polygon to circle, and finally becomes a circular annular shell. As required, a circular ring shell can be cut into four 90 ° elbows or six 60 ° elbows or elbows of other specifications. This process is applicable to manufacturing large elbows of any specification with the ratio of elbow pitch diameter to elbow inner diameter greater than 1.5. It is an ideal method for manufacturing large carbon steel elbows at present