Design of Welding Fixture For Long Seam Welding and Nozzle Welding Arrangement

Abstract

In the manufacturing of pressure vessel, welding is primary process by which different parts are joined to each other. In Pressure vessel manufacturing, submerge arc welding is widely used method for welding thick section. Welding is carried out in down hand position (1G Position) being a highly economical method for fabrication. In welding, welding fixture having a direct impact upon the weld Quality and Productivity.

Present work discusses design of welding fixture for longitudinal seam welding. In longitudinal seam welding two edges of the circular plate welded together along the length shell. Shell are fabricated either by rolling a single plate into cylindrical shell for smaller diameter or fabricated in circular segments for larger diameter and welded together.

In the current work, It is required to either modify the existing setup of long seam welding or designing a new setup in order to increase productivity and maximize floor utilization. Long Seam welding setup is designed for shell diameter range from 3000 mm to 6000 mm and shell length up to 3500 mm including run in/out. For a new design it is required to provide conceptual design considering various parameters like loading and unloading of shell, welding facility and space utilization. From diffrent conceptual design, the design which gives best performance is selected for long seam welding station.

In Nozzle welding arrangement, it is required to provide solution for the auto sagita adjustment in order to improve the weld quality. For the auto sagita adjustment main task is to keep the motors stationary of vertical slides as there is a loss of signal when it pass through the slip-ring. Nozzle welding arrangement is required to design for a nozzle diameter range from 250 mm to 1200 mm and sagita adjustment of up to 250 mm.