ACCELERATED STRESS CORROSION CRACKING SCREENING TEST METHOD FOR HY-130 STEELS

ACCELERATED SMALL SPECIMEN SCREENING TESTS FOR SCC RESISTANCE ARE NECESSARY FOR COST/TIME EFFICIENT EVALUATION OF WELD/BASE METAL FORMULATIONS IN WELD OR ALLOY DEVELOPMENT PROGRAMS AND FOR QUALITY CONTROL OF WELDED HY-130 STEELS. TEST DATA THAT IS CAPABLE OF MEASURING THE STRESS INTENSITY FOR CRACK INITIATION IN CATHODICALLY PROTECTED VESSELS IN NATURAL SEA WATER IS NECESSARY FROM DESIGN CONSIDERATIONS. IN THIS PHASE I EFFORT, AN EXISTING ACCELERATED SCC TEST METHOD USING CHARPY-SIZED SPECIMENS WITH THE STARTER CRACK LOCATED AT DIFFERENT MICROSTRUCTURAL REGIONS OF THE WELD AND IN THE BASE METAL WILL BE USED TO GENERATE PRELIMINARY, BASE-LINE DATA AT THE ONSET OF THE PROGRAM. CONCURRENTLY, A SCALED-UP VERSION OF THE EXISTING ACCELERATED SCC TESTING PROCEDURE WILL BE DESIGNED AND BUILT TO TEST FULL THICKNESS WELDED PLATES. IN EFFECT, THE MODIFIED DESIGN WILL CHANGE THE CURRENT CONSTANT LOAD CANTILEVER BEAM TEST TO A DISPLACEMENT CONTROLLED, SLOW STRAIN RATE TEST. QUANTITATIVE KISCC MEASUREMENTS OF VARIOUS MICROSTRUCTURAL REGIONS OF THE WELD WILL BE COMPARED TO SMALL SPECIMEN FULL-THICKNESS TEST RESULTS FOR BOTH AS-WELDED AND STRESS-RELIEVED WELDS. EXTREMES WITH REGARD TO SCC WILL BE USED TO ILLUSTRATE THE FEASIBILITY OF THE METHOD AS A QUALITY CONTROL TEST.