The stress and deformation of the
ERW pipe will produce stress and deformation on the surface of the ERW pipe as long as it is welded in the production process of the ERW pipe, but the degree is different. The welding stress and deformation caused by the welding process of ERW welded pipe often reduce the quality of welded products and even cause cracks. The change of weld size and shape caused by welding deformation may not be connected with other pipes or the allowance of machining allowance can not be cut off. Below we say the pressure and the deformation.
First of all, the surface stress of steel tube. When the material can not generate displacement under external force, its geometric size will change. This kind of deformation is called strain. When the material is deformed, its internal size is the same, but opposite to the direction of the external force reaction, the internal force distribution at the concentrated point is called stress, the stress and the microarea are internal forces, or the objects are deformed due to external factors (stress, temperature change, etc.), and the internal forces interact with each other in order to resist the external force. The reason is the effect and tries to make the object return to the pre deformed position from the deformation position.
From a mechanical point of view, deformation refers to changes in the shape of a structure (or part thereof). Any structure is made of deformable solid material and will be deformed and displaced under the action of external force. In the process of pipeline production, even if the correction can be carried out, such as mechanical correction or flame correction, both time-saving and labor-saving, additional stress of the pipeline is added, and the construction of negative tube is used. Therefore, we must understand the causes and dimensions of welding stress and deformation, and how to reduce and avoid welding stress and deformation.
