Senior research engineer, The Foundation of Scientific and Industrial Research at the University of Trondheim (SINTEF),
Pages: 21 Published: Jan 1978
The fatigue performance of steel weldments can be improved significantly by remelting the toe region using standard tungsten inert gas (TIG) equipment. While the cost of TIG dressing is much lower than for comparable methods, the TIG process causes an increase in maximum hardness in the base metal adjacent to the remelted material. This may preclude the use of the TIG method for some applications. The hardness distribution in TIG dressed T- joints of St 52.3N and NVE 36 steel plates with thickness ranging from 20 to 38 mm was studied. A modified TIG dressing technique involving a second (tempering) run was developed, and a substantial reduction in maximum hardness as compared with conventional TIG dressing was obtained. Fatigue tests were performed on specimens with load carrying fillet welds in the as-welded and TIG-dressed conditions. The material was a quenched and tempered steel with a yield strength of 880 MN/mm2 (128 ksi). The increase in fatigue strength at the endurance limit due to TIG dressing amounted to approximately 65 percent.
fatigue tests, weldments, hardness in welded joints, fatigue (materials), fatigue strength at N cycles, gas tungsten arc welding
Paper ID: STP33392S