System inflation welding method for stainless steel pipeline in large air separation cold box

Abstract

The invention relates to a system inflation welding method for a stainless steel pipeline in a large air separation cold box. The system inflation welding method comprises the following steps that a scaffold for welding and a temporary operation platform are built; the stainless steel pipeline is overall divided into a plurality of systems, and each system is divided into a plurality of subsystems; the stainless steel pipeline is hoisted in position and assembled; the systems are isolated through special blind plates, and the subsystems are isolated through temporary blind plates; the subsystems are subjected to inflation welding and radiographic inspection; the temporary blind plates are dismounted, and the systems are subjected to inflation welding and radiographic inspection; the systems are replaced with dry oilless air; air pressure testing is carried out; the special blind plates are dismounted, and the stainless steel pipeline is overall subjected to inflation welding and radiographic inspection; and finally the stainless steel pipeline is overall subjected to airtightness testing and system recovery. According to the system inflation welding method, the construction efficiency is improved, the construction period is shortened, waste of a large amount of argon is avoided, cost is reduced, high-altitude repeated inflation is avoided, and the construction risk is reduced.

Description

technical field [0001] The invention belongs to the technical field of air separation cold box construction, in particular to a system inflation welding method for stainless steel pipes in a large air separation cold box. Background technique [0002] The working temperature in the air separation cold box is cryogenic (about -190°C), so the welding quality requirements for the stainless steel pipes inside the air separation cold box are very high. The welding of stainless steel pipes in the air separation cold box is usually protected by argon filling welding, so that no oxides will be produced inside the pipes to ensure the welding quality. However, the process flow of the stainless steel piping system in the air separation cold box is complicated, and the general argon-filled protective welding method needs to inflate each welding joint in turn. The construction efficiency is low, the construction period is long, and the argon gas is wasted. Narrow, in turn to each weldin...

AI Technical Summary

Problems solved by technology

However, the process flow of the stainless steel piping system in the air separation cold box is complex, and the general argon-filled protective welding method needs to inflate each welding joint in turn, resulting in low construction efficiency, long construction period, more waste of argon gas, and the space inside the air separation cold box It is narrow, and there is a big potential safety hazard for each welding port inflated welding