A method of manufacturing welded steel pipes for the chord arm of crawler cranes

Abstract

The invention discloses a manufacturing method of a welding steel pipe for a crawler crane string abdomen arm. The manufacturing method includes the following steps of (1), steel plate preparation; (2), bending forming; and (3), high-frequency welding. Compared with the prior art, the manufacturing method has the following beneficial effects that (1), a steel plate is bent and welded into a steelpipe, a series of defects generated when a seamless steel pipe is applied to the crawler crane string abdomen arm are overcome, and the manufactured welding steel pipe can well meet the technical requirements of the crane string abdomen arm; (2), the steel plate is gradually bent into a W type and then subjected to closed forming, the purpose that after the steel plate is bent, two longitudinal sides are longitudinally straight, and no height fall exists in the transverse direction is achieved, the stability generated during welding is achieved, and the problem that in C type bending in the prior art, rebounding force of the steel plate is too large, and welding is not stable is solved; and (3), the method has simple steps and is convenient to operate.

Description

technical field [0001] The invention relates to the field of manufacturing welded steel pipes, in particular to a method for manufacturing welded steel pipes used for the chord arm of a crawler crane. Background technique [0002] Crawler crane is a boom rotating crane that uses crawlers to walk, and it is an indispensable main lifting equipment for engineering hoisting operations. Since the operating characteristics of crawler cranes determine that they are special and safety equipment, strict requirements are put forward for safety indicators. [0003] The steel pipes used in the existing conventional crawler crane chord arms are all seamless steel pipes, which are made of solid round bars that are pierced and rolled into hollow steel pipes, and then made by head making, pickling, cold drawing, heat treatment and straightening. However, due to the limitation of the manufacturing process of the seamless steel pipe, the decarburization of the inner and outer surfaces of the...

AI Technical Summary

Problems solved by technology

[0003] The steel pipes used in the existing conventional crawler crane chord arms are all seamless steel pipes, which are made of solid round bars that are pierced and rolled into hollow steel pipes, and then made by head making, pickling, cold drawing, heat treatment and straightening. However, due to the limitation of the manufacturing process of the seamless steel pipe, the decarburization of the inner and outer surfaces of the seamless steel pipe is difficult to control, and the wear resistance of the workpiece is poor, so it is difficult to meet the design requirements of the crawler crane chord arm, and the radial direction of the seamless steel pipe There is a large difference in wall thickness, and defects such as pits, pits, and warped skins on the surface of the steel pipe cannot be avoided during perforation, which makes it easy to form anti-corrosion omissions after assembly and spraying of the crane webbing arm. Therefore, seamless steel pipes with poor comprehensive performance have gradually Unable to adapt to the development trend and needs of the crane industry, so technicians thought of using steel strips rolled into welded steel pipes instead of seamless steel pipes to improve the safety indicators of cranes

[0004] However, the existing welded steel pipes are directly subjected to C-shaped bending when the steel strip is rolled and welded. Since the steel strip has rebound force when bending, the thicker the steel strip, the greater the rebound force, which greatly affects the The stability of welding affects the quality of the subsequent welded steel pipes. Due to the poor quality of the welded steel pipes, they cannot meet the technical requirements of the crane web jib

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