Fracture behaviour of welded joints fabricated in HSLA steels of differentstrength level

Effects of strength differences (mismatch) between weld metal and two base metals, as well as local variations of strength within weld HAZ zones, on t he fracture toughness properties of welded joints were discussed. Due to hi gh global weld joint mismatch, fracture deviation from CGHAZ into weld or b ase metal occurred. This event occurred in both weld joints provided on ste els of equal and different strength level. Therefore, the result was not a correct measurement of HAZ fracture toughness. The significance of the loca l crack tip opening displacement measurement technique was also discussed b y comparing the CTOD results of delta(5) and British Standard delta(BS) Som e differences in the two methods were discussed, in particular, for CGHAZ t oughness weld joints provided on steels of equal and different strength lev el. (C) 1999 Elsevier Science Ltd. All rights reserved.