Automatic argon arc seal welding method for narrow gap between deep grooves of tube plate and heat exchange tube

Abstract

The invention discloses an automatic argon arc seal welding method for a narrow gap between deep grooves of a tube plate and a heat exchange tube. The method comprises the following steps that the groove is subjected to polishing cleaning and washing; the tube plate and the heat exchange tube are assembled; a positioning pneumatic expansion sleeve of an automatic tungsten argon-arc welding gun is inserted into the inner wall of the heat exchange tube and is inflated to be expanded; an included angle between a tungsten axis of the welding gun and an axis of the heat exchange tube is adjusted to 12.5-17.5 degrees; after adjustment, the tungsten end part of the welding gun is positioned in the middle of the groove and points to the roots of the grooves of the tube and the tube plate; in the groove, four layers of weld passes are distributed from the bottom of the groove to the surface of the groove, wherein the first layer of backing weld is self fluxing without welding wires, and other three layers are filled with metal wires; in each layer of single-pass weld, a tungsten electrode adopts a cerium tungsten electrode; and after the first layer is welded, welding is stopped, the next layer of welding is carried out step by step until the welding is finished after the weld joint quality is not abnormal. According to the automatic argon arc seal welding method, the quality of deep and narrow groove seal welding is increased, the welding work efficiency is increased, the appearance of weld joints is attractive, the fusing is good, and the inner parts of the weld joints do not have any defect.

Description

technical field [0001] The invention relates to an argon-arc sealing welding method, in particular to an automatic argon-arc sealing welding method with a deep groove and narrow gap between a shell-and-tube heat exchanger tube plate and a heat exchange tube, and belongs to the technical field of argon-arc welding methods. [0002] Background technique [0003] At present, in the field of heat exchangers and reactors in China, the depth of the tube-sheet sealing welding groove generally does not exceed 2mm. If it exceeds this depth, it will bring great inconvenience to the welding workers. [0004] If you encounter a heat exchanger with a complex structure of tube sheets and heat exchange tubes, one of the core technologies for its manufacture is to seal and weld the heat exchange tubes and tube sheets. The gap is narrow, with a depth of 4-5mm and a width of 4mm. The deep and narrow structure of the groove brings great inconvenience to the welding work. First, because the gr...

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Problems solved by technology

[0006] The purpose of the present invention is to provide an automatic argon arc sealing welding method between the tube plate and the heat exchange tube with deep groove and narrow gap, so as to solve the problem that th...

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