Residual Stresses In Weld Component

Jitendra malavNo:09

Residual Stressesstresses that would exist in a body if all

external loads were removed. They are sometimes called internal stressesCaused by to non uniform temperature in

welding

Formation of Residual stressesResulting for mismatch . Produced by unevenly distributed non elastic

strain Thermal stress and resulting residual stressResidual stress and reaction stress in

weldment

Residual Stress in weldHeat flows from the weld area and causing

the joint area to expandThermal expansion and contraction due to

welding can leave behind permanent stressHigher heat input welds are more prone to

residual stress Increased restraint can decrease distortion

but can result in higher residual stress

Residual tensile stresses exist in the weld metal and the adjacent base metal

While residual compressive stresses existing the areas farther away from the weld metal

Effect of residual stressesDecrease the fracture strength.Reduce buckling strength. Compressive residual stress increases fatigue

strengthIn hostile environment residual stress can

causes cracking in matel without any applied load.

Reducing residual stressesSelecting appropriate processes, procedures,

welding sequence and fixturing. Selecting best method for stress reliving and

removing distortion. Selecting design detail and materials to

minimize the effect of residual stresses

Measurement of residual stressesStress-relaxation techniquesX-ray diffraction techniquesTechniques using stress-sensitive propertiesCracking techniques

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