Influence of Reinforcement on Corrosion Fatigue Strength of Welded Joints

Abstract

In this paper, the corrosion fatigue behaviors of as-welded specimens, welded and machined specimens under plane bending cantilever machine, and artificially notched specimens at the H. A. Z. of weld bead under rotary bending cantilever machine were investigated in the dripping of 3% salt water.
Tested materials were mild steels, and welding procedures were performed by submerged arc welding.
The relations between the strength reduction factor βk due to the stress concentration factors of the reinforcement or the artificial notches, the factor βc due to corrosion, and the factor βkc, that by the gathering effects of corrosion with reinforcement or artificial notches, are discussed.
The following conclusions may be drawn from these test results.
(1) At the 10⁷ cycles, the corrosion fatigue strength under dripping salt water was reduced by 40-50% than in air.
(2) In the plane bending, the factor βkc was nearly equal to βk×βc, but in the rotally bending, the factor βkc was smaller than βk×βc.
(3) In the corrosion fatigue test, the welded metals did not form the weak zone for the initiation of cracks so far as the surfaces were smoothly machined.