Heat treatment and machining is a very important in Transformer corrugated fin wall making machine manufacturing process.
What is Welding Stress and Welding Deformation?
Welding stress is the internal stress existing in the weldment during and after the welding process. Welding deformation is the change of weld size caused by welding.
Which reasons cause Welding Stress and Deformation?
1. Non-uniform Heating of Welds
(1) The stress and deformation of unconstrained rods during uniform heating belong to free deformation, so there will be no internal stress during heating and no residual stress and deformation after cooling.
(2) The stress and deformation of the restrained bar under uniform heating. If the heating temperature is higher and reaches or exceeds the material yield point temperature (T>TS=600), compressive plastic deformation will occur in the bar. The internal deformation consists of elastic deformation and plastic deformation.
(3) Stress and Deformation Induced by Central Heating of Long Slab (Similar to Surfacing)
(4) Stress and Deformation Caused by Heating on One Side of Long Slab (Equivalent to Surfacing on the Edge of Slab)
2.The shrinkage of weld metal.
When the weld metal is cooled and transformed from liquid to solid, its volume will shrink. As the weld metal is closely related to the base metal, the weld metal can not shrink freely. This will cause the deformation of the whole weldment and the residual stress in the weld.
3.Changes in Metal Microstructure
The metallographic structure of steel changes during heating and cooling. The specific volume of these structures is different, which will also cause welding stress and deformation.
4.Rigidity and restraint of Weldments
The greater the rigidity of the weldment itself and the degree of restraint around it, the smaller the welding deformation and the greater the welding stress; conversely, the smaller the rigidity of the weldment itself and the degree of restraint around it, the greater the welding deformation and the smaller the welding stress.
Rigidity – refers to the ability of weldments to resist deformation.
Constraint – The constraints on welding deformation imposed by objects around the weldment.
Why JTFY Transformer corrugated fin wall making machine need be heat treated?
All work is to insure whole machine running with high precision and stable, to guarantee produce high precision transformer corrugated tank wall.