What causes residual stresses?
Process
Casting
Machining like grinding, turning, milling etc.
Heat treatment
Joining, like welding
Mechanial influence
Plastic deformation caused by material-removal-process
Shrinkage
Thermal influence
Temperature-gradient during cooling
Gradient caused by friction
Temperature-gradient during cooling and heating
Temperature-gradient during cooling and heating
Microstructure
Phase transformation
Phase transformation during machining- process at elevated temperature
Phase transformation
& volume change
Phase transformation (HAZ)