# Wahl Correction Factor

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Wahl correction factor, abbreviated as K, also called Wahl factor, Wahl stress factor or spring stress correction factor, a dimensionless number, is a measure of the degree to which external stress is amplified at the curvature of the spring coil.  It is used in stress analysis and engineering to account for the stress concentration effect caused by changes in the cross-sectional shape or discontinuities in a structural member.

When a structural component has a geometric irregularity, such as a hole, fillet, or notch, the stress distribution around that irregularity becomes non-uniform, resulting in stress concentration.  The Wahl correction factor is applied to adjust the calculated stress in the vicinity of the irregularity to account for this concentration effect.  The Wahl correction factor is specific to the type and geometry of the irregularity and is determined based on empirical data or experimental results.  It depends on parameters such as the shape, size, and orientation of the irregularity, as well as the material properties of the structural member.

The Wahl correction factor is commonly used in conjunction with stress concentration factor calculations to estimate the maximum stress in a component or to assess the fatigue life and structural integrity of a structure.  It helps engineers account for the localized stress intensification caused by geometric irregularities and ensures more accurate and conservative stress predictions.  It's important to note that the Wahl correction factor is specific to certain types of stress concentration, and different correction factors may be used for different types of irregularities.  Therefore, it is crucial to consult relevant design codes, handbooks, or specialized references to obtain appropriate Wahl correction factors for specific irregularities or stress concentration scenarios.

## Wahl correction factor formula

$$K = \frac{ 4\;C \;-\; 1 }{ 4\;C \;-\; 4 } + \frac{ 0.615 }{ C }$$
Symbol English Metric
$$K$$ = stress correction factor $$dimensionless$$
$$C$$ = spring index $$dimensionless$$