Stainless steel sheet is often deformed by welding in welding process for many reasons.
In order to control the deformation in welding, it is necessary to understand the influence of welding methods on welding deformation.
Related reading: How to Fix Stainless Steel Welding Deformation?
Most welding methods need to take production efficiency and welding quality into account, so welding methods, processes and welding procedures will significantly affect the level of welding deformation.
Therefore, the welding method used must have higher deposition efficiency and as few weld beads as possible.
In addition, the heat input should be small.
Generally, the welding methods for stainless steel sheet include single side submerged arc welding, double side submerged arc welding, flux cored wire arc welding, inert gas shielded welding, active gas shielded welding, etc.
The influence of welding heat input on welding residual stress and deformation is recognized by the industry.
Therefore, under the condition of ensuring good weld formation, small welding heat input shall be used as much as possible to ensure that the minimum welding stress and deformation can be obtained.
How to control welding heat input includes reasonable selection of welding current, welding voltage and welding speed.
For TIME welding, the ratio of ternary or quaternary shielding gas should also be considered.
The influence of stainless steel plate thickness on welding deformation decreases with the reduction of plate thickness, which is also the main reason why it is difficult to control the welding deformation of stainless steel plate.
In addition, the quality control of welding deformation of stainless steel sheet includes from the cutting of stainless steel sheet to clamping, spot welding, welding process, post welding treatment, etc., in which the adopted welding method and effective deformation control measures should also be considered.
The influence of cutting method and cutting quality on welding deformation of thin plates is smaller than that of plasma cutting due to the concentration of laser heat source and fast cutting speed, and the proportion in the subsequent residual stress accumulation process is also small.
The cutting accuracy has a significant impact on the guarantee of the welding gap.
The unevenness of the plate edge caused by plasma cutting makes the plate bulge in the middle after spot welding, while the plate cut by laser keeps a relatively flat surface after spot welding.
Spot welding can not only ensure the welding gap, but also have a certain anti-deformation ability.
However, it is necessary to consider the number, size and distance between spot welds.
For the deformation of stainless steel sheet, the spot welding process is not suitable for generating considerable residual welding stress before welding, which will affect the subsequent accumulation of welding residual stress.
Too small spot welding size may lead to cracks during welding and the welding gap can not be guaranteed, and too large spot welding size may lead to lack of penetration at the back of the weld bead and affect the integrity of the joint.
The order of spot welding and the reasonable selection of spot welding distance are also very important, and the influence results are described in many literatures.
Assembly stress and welding procedure shall minimize the stress caused during welding and assembly.
If the stress exceeds the critical stress for deformation, deformation may occur.
Different welding procedures have different effects on welding residual stress.