NONDESTRUCTIVE MEASUREMENT OF RESIDUAL STRESSES IN POWERPLANT PIPING WELDS USING MAGNETOELASTIC TECHNIQUES

A METHOD TO MEASURE NONDESTRUCTIVELY THE BIAXIAL RESIDUAL STRESSES IN FERRITIC PIPING WELDS WITHIN FOSSIL-FIRED AND NUCLEAR-POWERED ELECTRICITY GENERATING PLANTS IS PLANNED. THE METHOD USES THE MAGNETICALLY INDUCED VELOCITY CHANGES OF ULTRASONIC WAVES TO DETERMINE THE STRESSES. IT IS BEING SHOWN THAT THE METHOD CAN DETERMINE THE ABSOLUTE VALUES, SIGN, AND ORIENTATION OF THE AXIAL AND CIRCUMFERENTIAL STRESS COMPONENTS. PHASE I DEMONSTRATES THE FEASIBILITY OF THE PROPOSED METHOD THROUGH EXPERIMENTS ON PIPE WELD SPECIMENS TOGETHER WITH MODELING AND SOFTWARE DESIGN FOR DATA ANALYSIS AND DISPLAY. IN PHASE II, THE AVAILABLE HARDWARE FOR EXPERIMENTATION WILL BE MINIATURIZED AND INTEGRATED WITH THE SOFTWARE TO YIELD A PORTABLE PERSONAL COMPUTER-BASED SYSTEM FOR FIELD IMPLEMENTATION.