How Validates Residual Stress Effect on Fatigue Strength and SCC Evaluations?

The availability of several processes for residual stress control is discussed in order to verify residual stress effect on fatigue strength and SCC evaluations The effectiveness protecting from fatigue and stress-corrosion cracking is validated by numerical analysis and actual experiment. In-process control during welding is the easiest method to reduce residual stress without any treatment after welding process. Control of welding pass sequence for multi-pass weld is applied to cruciform joints and butt-joints with X-shaped groove. Other processes after welding are confirmed the validity of residual stress improvement. Water jet peening is useful for obtaining compressive residual stress on the surface, and the tolerance against both fatigue and stress-corrosion cracking is verified. Cladding of corrosion-resistant material is also effective for preventing stress-corrosion cracking by the metallurgical respect on the basis that residual stress at the interface to base metal should be considered carefully. The residual stress of the base metal near the clad edge is confirmed within the tolerance of crack generation. Controlling methods both during and after welding processes are found to be effective for assuring the integrity of the welded components.