Inner hole rotary argon arc welding gun head of pipe and pipe plate and welding method

Abstract

The invention discloses an inner hole rotary argon arc welding gun head of a pipe and a pipe plate and a welding method, and relates to the field of welding of heat exchanger pipe fittings and pipe plates. The gun head is mainly composed of a conductive mandrel, a tungsten electrode, an upper positioning insulation sleeve, a lower positioning insulation sleeve and an adjustable nut, the upper positioning insulation sleeve sleeves the upper part of the exterior of the conductive mandrel, the upper part of the upper positioning insulation sleeve is integrally connected with an annular plate for hanging and fixing the whole gun head, the adjustable nut is in threaded connection with the exterior of the upper positioning insulation sleeve, and a protective gas hole is formed in the conductive mandrel. An inlet of the protective gas hole is formed in the axial direction of the conductive mandrel, an outlet is located in the lower portion of the conductive mandrel and extends to the outer side of the conductive mandrel in the radial direction, the tungsten electrode is located below the protective gas hole, the lower positioning insulation sleeve further sleeves the bottom of the conductive mandrel, and a compression screw is further arranged on the bottom face of the conductive mandrel. An argon protective sleeve is further adopted during welding. According to the inner hole rotary argon arc welding gun head and the welding method, the stress corrosion resistance and crevice corrosion resistance stability of a connector are improved, and the safe use performance of equipment is improved.

Description

technical field [0001] The invention relates to the welding field of heat exchanger tube fittings and tube sheets, in particular to a rotary argon arc welding torch head and a welding method for the inner holes of the tubes and tube sheets. Background technique [0002] Heat exchangers are widely used equipment in the petrochemical industry, and the connection of tubes and tube sheets is an important process in the manufacturing process. The joints are generally end welded joints (such as figure 1 ), for equipment with corrosive stress, because the gap between the tube and tube sheet exists in the working condition, the corrosive medium gathers to form a certain residual stress, resulting in stress corrosion; at the same time, the weld is exposed to the front of the corrosive fluid Scouring effect, easy to corrode and crack, greatly reducing the service life of the equipment. Therefore, it is necessary to improve the existing welding method. Contents of the invention ...

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Problems solved by technology

[0003] In order to solve the problem of small inner hole, inconvenient wire addition, and thin tube wall in the welding of heat exchangers, and the heat exchange tube is a coil tube, the conventional back protection cover cannot meet the requirements, and the tube head protrudes inwards. It is difficult to ensure a tight fit with the tube sheet, and a rotating argon arc welding torch head and welding method for the inner hole of the tube and the tube sheet are provided

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