Residual stresses arise from material fabrication, surface treatment and any other process that introduces permanent deformation. They exist independently of external loading and have a significant effect on fracture resistance and component life in many critical applications.
Near Surface Stress Distributions
BEAR now offers a wide range of residual stress measurements that include: near surface stress distributions due to shot peening, laser treatment, welding, machining and heat treatment of parts with flat or curved surfaces such as a valve seat inside a valve body as shown below:
Through-Thickness Stress Distributions
BEAR can also measure through-thickness stress distributions due to welding, fabrication and heat treatment. Examples include fillet and butt welds, and water-quenched and cladded parts.
Our high-precision, through-thickness residual stress measurements are based on the compliance and single slice methods. The first method uses the strains measured when a cut of progressively increasing depth is introduced by wire electric discharge machining to obtain the stress normal to the faces of the cut. The second method uses the strains measured when a thin slice is removed from a mid-section of a part to obtain a 2-D distribution of the axial stress.
Production Components
BEAR can implement, or assist your engineers in implementing, a proven ultrasonic method to check strategic locations. This method is based on refracted longitudinal wave measurement and is calibrated using our high-precision slice method and Finite Element Analysis of the subject part.
