The deformation caused by the welding process directly affects the performance and use of the welded steel pipe, so it is necessary to use different welding processes to control and prevent the deformation of the steel pipe, and to correct the components that produce welding deformation.
Types of welding deformation
There are 7 forms of welding deformation.
① Longitudinal shrinkage deformation: shrinkage along the length of the weld.
② Lateral shrinkage deformation: transverse shrinkage perpendicular to the direction of the weld.
③ Angular deformation: the angular displacement around the axis of the weld.
④Deflection deformation: bending deformation caused by asymmetrical shrinkage of the neutral axis of the component.
⑤ Instability and deformation: under the action of welding residual compressive stress, the thin-walled structure is locally unstable and wavy;
⑥Wrong side deformation: the wrong side in the thickness direction caused by inconsistent expansion of the welding edge during the welding process.
⑦ Distortion deformation: deformation caused by irregular longitudinal and lateral shrinkage of the weld due to poor assembly and unreasonable welding procedures.
Prevention and Control of Welding Deformation
The size of welding deformation is related to the size, quantity and arrangement of welds. First of all, it is very important to reasonably determine the number of welds, the shape and size of the groove from the design, and properly arrange the position of the welds to reduce deformation.
Correction of welding distortion
Welding deformation is often corrected by mechanical means. For the deformation of the thin plate shell structure caused by long and regular butt welds, a good correction effect can be obtained by rolling the weld and its two sides with a steel wheel. The flame straightening method, which uses local heating to produce compression plastic deformation to shrink the long weldment after cooling, has the advantages of strong mobility and simple equipment, and has been widely used.
Types of welding deformation
There are 7 forms of welding deformation.
① Longitudinal shrinkage deformation: shrinkage along the length of the weld.
② Lateral shrinkage deformation: transverse shrinkage perpendicular to the direction of the weld.
③ Angular deformation: the angular displacement around the axis of the weld.
④Deflection deformation: bending deformation caused by asymmetrical shrinkage of the neutral axis of the component.
⑤ Instability and deformation: under the action of welding residual compressive stress, the thin-walled structure is locally unstable and wavy;
⑥Wrong side deformation: the wrong side in the thickness direction caused by inconsistent expansion of the welding edge during the welding process.
⑦ Distortion deformation: deformation caused by irregular longitudinal and lateral shrinkage of the weld due to poor assembly and unreasonable welding procedures.
Prevention and Control of Welding Deformation
The size of welding deformation is related to the size, quantity and arrangement of welds. First of all, it is very important to reasonably determine the number of welds, the shape and size of the groove from the design, and properly arrange the position of the welds to reduce deformation.
Correction of welding distortion
Welding deformation is often corrected by mechanical means. For the deformation of the thin plate shell structure caused by long and regular butt welds, a good correction effect can be obtained by rolling the weld and its two sides with a steel wheel. The flame straightening method, which uses local heating to produce compression plastic deformation to shrink the long weldment after cooling, has the advantages of strong mobility and simple equipment, and has been widely used.
