Weld Residual Stress Calculator
Estimate residual stress magnitude and distribution based on welding parameters and restraint conditions.
Residual Stress Characteristics
| Location | Stress Type | Magnitude |
|---|---|---|
| Weld centerline | Longitudinal | Tension (max) |
| HAZ region | Longitudinal | Tension (high) |
| Away from weld | Longitudinal | Compression |
| Weld ends | Transverse | Tension |
| Weld center | Transverse | Lower tension |
Understanding Weld Residual Stress
Origin of Residual Stress
- Thermal Expansion/Contraction: Heated weld metal expands then contracts on cooling against cooler surrounding material
- Phase Transformations: Volume changes during solid-state transformations (austenite to martensite)
- Plastic Strains: Yielding during thermal cycle leaves permanent strain incompatibilities
- Restraint: External restraint prevents free contraction, increasing residual stress
Typical Stress Distributions
- Longitudinal: Tensile at weld (up to yield), compressive away from weld (self-equilibrating)
- Transverse: Tensile at weld ends, varies along length
- Through-Thickness: Usually lower magnitude, varies with joint type
Effects of Residual Stress
- Fatigue: Tensile residual stress reduces fatigue life
- SCC: Stress corrosion cracking requires tensile stress
- Brittle Fracture: Increases risk at low temperatures
- Distortion: Residual stress released during machining causes movement
Stress Relief Methods
- PWHT: 60-85% reduction typical, temperature and time dependent
- Vibratory: 20-40% reduction, less effective than thermal
- Peening: Introduces beneficial compressive surface stress
- Mechanical Overload: Can redistribute but not eliminate stress