Intermediate Stress Relief
Activity carried out to reduce residual stresses and diffuse hydrogen from completed highly stressed weld joints so that the risk of cracking is minimized upon the weld joint cooling to ambient temperature.
- NOTE: Intermediate stress relief (ISR) may be used to reduce the risk of decreasing the base material properties when multiple welding operations are performed on a component. For example, a flange may receive an ISR after the seal groove inlay, then receive the final PWHT after the flange has been circumferentially welded to its mating component.
Source: API STANDARD 16AR, Standard for Repair and Remanufacture of Drill-through Equipment, First Edition, April 2017. Global Standards