Carbon steel elbow design and manufacture must consider the hardness of carbon steel elbow, carbon steel elbow heated to a certain temperature and thermal insulation for some time, and then make it slowly cooling, called annealing. The annealing of hot pressing elbow is to heat the steel to the temperature of the phase transition or part of the phase transition, and the heat treatment method after heat preservation. The purpose of annealing is to eliminate the defects of the organization, to improve the composition uniformity and to refine the griain size, to improve the mechanical properties of the hot press, and to reduce the residual stress.

      Carbon steel elbow is steel hot pressing molding or forging play forming different diameter pipe and its connection form is directly to the different diameter pipe and steel pipe butt welding, concentric different diameter pipe of the main manufacturing standards is generally GB/T12459, GB/T13401, ASME B16.9, SH3409, HG/T21635, HG/T21631, SY/T0510. Corresponding to the concentric reducer, the material has carbon steel, alloy steel and stainless steel.

      Carbon steel elbow is widely used in industries, oil, natural gas, chemical, water, electricity, construction, boiler and so on pipeline butt welding elbow and molding process is complex and need according to different materials and use of welding, under a certain pressure is gradually forming.

      The advantages of the forming process of carbon steel elbow are mainly reflected in the following aspects:

      One, do not need to billet is used as a raw material, save the tube making equipment and the mold expense and arbitrary large diameter and wall thickness relatively thin head size can be obtained. The size of the raw material is relatively special, do not need to join the tube blank material, easy to control during processing.

      Two, without tube blank as raw material, can save pipe equipment and tooling costs, and can be arbitrarily large diameter and wall thickness of the relatively thin carbon steel elbow.

      Three, due to the above two reasons, can shorten the manufacturing cycle, production costs greatly reduced. Because does not need and special equipment, eapecially suitable for on-site processing of carbon reducer.

      Carbon steel elbow first welding a cross-sectional polygon polygon ring shell or closed at both ends of the multiple edges of fan-shaped shells, interior flushes the full pressure medium, subjected to internal pressure, internal pressure under the effect of cross section by the polygon gradually became round, eventually becoming a circular ring shells. According to the need, a circular ring shells can be cut into four 90 101 elbow or six 60 101 elbow or other specifications of the elbow and the technology application in manufacturing bend diameter and bend diameter ratio greater than 1.5 any specification of large elbow, is currently making the ideal method for the large carbon steel elbow.