Performance Improvement of Friction Stir Welds by Better Surface Finish Project Manager(s)/Lead(s) machining (EDM) notches placed in and along the weld. Then samples will be cut from these panels and Sam Russell/EM20 pulled in a tensile test machine to measure the strength (256) 544–4411 of the shaved and unshaved panels. Mindy Nettles/XP50 The baseline self-reacting-friction stir weld (SR-FSW) (256) 544–1569 panels include (a) eight baseline panels that have been welded and PAUT tested, (b) two baseline panels that Sponsoring Program(s) have been machined into tensile specimens for room temperature, liquid nitrogen (LN ), and liquid hydro- 2 Human Exploration and Operations Mission Directorate gen (LH ) testing; this work is complete, (c) five base- 2 Space Launch System Advanced Development line panels that have been laid out for EDM notches; this work is complete, and (d) one EDM notched base- Project Description line panel that has been given to EM10 to measure the notches; however, they are having trouble measuring The as-welded friction stir weld has a cross section that the notches. A few work-arounds are currently being may act as a stress concentrator. The geometry associ- assessed. ated with the stress concentration may reduce the weld strength and it makes the weld challenging to inspect The SR-FSW panels with raised weld land (~0.025 inch) with ultrasound. In some cases, the geometry leads to include (a) one panel with raised weld land, welded to false positive nondestructive evaluation (NDE) indica- determine the best method for machining the raised tions and, in many cases, it requires manual blending weld-land, (b) seven panels with raised weld land have to facilitate the inspection. This study will measure the been welded and PAUT inspected; these panels had stress concentration effect and develop an improved a slight ridge that was not machined off and was hand phased array ultrasound testing (PAUT) technique for sanded to remove the slight ridge, then reinspected friction stir welding. with PAUT (five panels were identified for probability of detection inspections), (c) two panels with raised Post-welding, the friction stir weld (FSW) tool would weld land have been machined into tensile specimens be fitted with an end mill that would machine the weld for room temperature, LN , and LH testing; this work 2 2 smooth, trimmed shaved. This would eliminate the is complete, and (d) five panels with raised weld-land need for manual weld preparation for ultrasonic inspec- have been laid out for EDM notches; the work has been tions. Manual surface preparation is a hand operation scheduled. that varies widely depending on the person preparing the welds. Shaving is a process that can be automated References and tightly controlled. Crumbly, C.M.; Bickley, F.P; and Hueter, U.: “Space Notable Accomplishments Launch System Spacecraft/Payloads Integration and Evolution Office Advanced Development FY 2014 Two sets of panels will be welded with FSWs. One set Annual Report,” NASA/TM—2015–218201, NASA will be prepared in the usual manner; the second set Marshall Space Flight Center, Huntsville, AL, January will be shaved by milling. These panels will be used to 2015. estimate the phased array testing detectability of defects in the surface. The defects will be electro-discharge 54 Joint Efficiency of Welded Panels at Room Temperature 0.85 0.83 0.81 0.79 y c n 0.77 e ci Effi 0.75 SL oint 0.73 Smoothed S J A 0.71 D As-Welded 0.69 0.67 0.65 Joint efficiency of welded panels at room temperature. Welded panel. 55