The technical treatment of the fully welded ball valve body
Addtime：2023-07-18 From： View：467
Everyone must have seen the valve body of a fully welded ball valve. They know that the welding joints are generally designed as narrow-gap thick-walled submerged arc welding, and most fully welded valve bodies are large-diameter cylindrical welded joints with extremely high thickness. Everyone must be wondering why this is the case, right?
Heat treatment technology processing
The thick-walled multi-layer welding process involves repeated heating and cooling of the metal material, resulting in the unevenness and deterioration of the welding joint structure, generating high residual stress, and even causing welding defects. Welding is the final process after the assembly of this product. There are non-metallic sealing materials such as rubber and polytetrafluoroethylene plastic inside the valve cavity, and post-weld heat treatment cannot be carried out.
2: Handling of the joint area
In the design of valve body welding joints, to ensure alignment and positioning, there is a circular gap at the root of the weld. Under the action of internal pressure and external loads, this gap will generate stress concentrations several times greater than the normal working stress. This also makes it difficult for engineers to handle.
The stress concentration, residual stress and poor microstructure at the root gap of the valve body welding joint have become the weak links in the valve body structure, attracting attention from the valve industry both at home and abroad. However, no relevant solutions to this problem have been reported yet, posing a potential hazard to the boundary integrity of this product structure.
Heat treatment technology processing
The thick-walled multi-layer welding process involves repeated heating and cooling of the metal material, resulting in the unevenness and deterioration of the welding joint structure, generating high residual stress, and even causing welding defects. Welding is the final process after the assembly of this product. There are non-metallic sealing materials such as rubber and polytetrafluoroethylene plastic inside the valve cavity, and post-weld heat treatment cannot be carried out.
2: Handling of the joint area
In the design of valve body welding joints, to ensure alignment and positioning, there is a circular gap at the root of the weld. Under the action of internal pressure and external loads, this gap will generate stress concentrations several times greater than the normal working stress. This also makes it difficult for engineers to handle.
The stress concentration, residual stress and poor microstructure at the root gap of the valve body welding joint have become the weak links in the valve body structure, attracting attention from the valve industry both at home and abroad. However, no relevant solutions to this problem have been reported yet, posing a potential hazard to the boundary integrity of this product structure.