Bead-welding method of inner wall of 90-degree bent pipe

Abstract

The invention discloses a bead-welding method of an inner wall of a 90-degree bent pipe for a large-scale pressure vessel, which can shorten the manufacturing cycle and effectively ensure the bead-welding quality of a transition layer and an anti-corrosion layer. The method is characterized in that the method comprises the following steps: a. selecting a pipe billet of a straight pipe; b. heating the pipe billet of the straight pipe in a furnace, taking out the heated pipe billet of the straight pipe, and performing compression moulding to the pipe billet on a pressing machine by a mould to form the 90-degree bent pipe, wherein the ovality of the formed 90-degree bent pipe is controlled to be less than or equal to 3%; c. performing bead welding to the surface of the inner wall of the formed 90-degree bent pipe by an automatic bead-welding machine for the inner wall of the bent pipe to form the transition layer; and d. performing bead welding to the surface of the transition layer to form the anti-corrosion layer by the automatic bead-welding machine for the inner wall of the bent pipe. According to the method, the pipe billet of the straight pipe is heated to be pressed into the 90-degree bent pipe, and then bead welding is directly performed in the 90-degree bent pipe to form the transition layer and the anti-corrosion layer, so that the working procedures can be greatly reduced, and the bend-welding quality of the transition layer and the anti-corrosion layer can be effectively ensured through ovality control.

Description

technical field [0001] The invention relates to an elbow forming method, in particular to an inner wall surfacing method for a 90° elbow of a large pressure vessel. Background technique [0002] With the rapid development of my country's petrochemical and oil refining industries, the demand for large pressure vessels continues to increase, and pressure vessels have become one of the key products of the group company. Improving the development of new processes and reducing the container manufacturing cycle are the highlights of the competition among major container manufacturers. [0003] In hydrogenation products, due to structural limitations, continuous stainless steel surfacing on the inner wall of the elbow cannot be achieved. It has always been a difficult problem in container production. The traditional elbow manufacturing process usually divides the 90° elbow into three sections and surfacing respectively. Reassembled and welded into a whole (see figure 1 ), the spe...

AI Technical Summary

Problems solved by technology

[0005] The 90° elbow manufactured by the above method has many processes such as groove processing, inner wall surfacing welding, circumferential seam welding, flaw detection and other processes, the manufacturing process takes a long time, and the production efficiency is low, which seriously affects the manufacturing cycle of hydrogenation products.

The assembly welding and flaw detection of the two circular seams in the middle of the elbow greatly increase the manufacturing cost, and the space position is limited when repairing the stack, which makes it difficult to guarantee the quality of the surfacing welding and increases the risk of product quality

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