Fatigue Resistance of HPS-485 W (70 W) Welded Butt-Splice Connections Using Narrow Gap Improved Electroslag Welding

The writers investigated the performance of narrow gap improved electroslag weld (NGI-ESW) procedures in welded butt splices using high-performance steel grade HPS-485 W (70 W) through comparison against similar specimens fabricated using submerged arc welding (SAW). Five NGI-ESW and five SAW specimens were tested in fatigue at very high stress ranges, and all achieved run-out at or above 2 million cycles. Two each of the specimens created using SAW and NGI-ESW were tested an additional 3 million cycles; the NGI-ESW specimens did not experience fracture, whereas one SAW specimen failed in the base metal and another completed the additional cycles without failure. All intact specimens were statically tested to failure and results were compared. All 10 specimens performed considerably better than predicted by the AASHTO (2007) fatigue life equation. The NGI-ESW specimens performed at least as well as the SAW specimens under fatigue and static testing, suggesting that inclusion of the NGI-ESW process in AWS D1.5 may be appropriate when used with HPS-485 W (70 W). Additionally, testing supports extension of current code provisions to the use of NGI-ESW in fracture-critical applications.