Local compression process avoiding toughness change

• Published in: Welding in the world Vol. 67; no. 3; pp. 607 - 615
• Main Authors: Ozawa, A. Takumi, Kosuge, B. Hiroaki, Mikami, C. Yoshiki, Kawabata, D. Tomoya
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2023; Springer Nature B.V
• Subjects: Chemistry and Materials Science; Crack propagation; Crack tips; Fatigue failure; Fatigue tests; Fracture toughness; Heat treating; Jigs; Ligaments; Materials Science; Metallic Materials; Numerical analysis; Research Paper; Solid Mechanics; Theoretical and Applied Mechanics; Fracture toughness value; Weld specimens; Local compression technique
• ISSN: 0043-2288; 1878-6669
• DOI: 10.1007/s40194-022-01386-2

The local compression technique is used to achieve a straight crack front in weld specimens. However, some interested parties have reported that it decreases the fracture toughness value. The authors investigated the better local compression condition for securing a straight crack front while maintaining the fracture toughness value by a numerical analysis, and as a result, some local compression conditions, which do not involve compression of the crack tip, identified as promising. Fracture toughness tests were also conducted with these local compressions, and the test results showed that the fatigue precrack shape and fracture toughness value follows those estimated tendency by the numerical analysis. Two local compression conditions, which compress at the future notch side and ligament side by a square jig and at the ligament side by a circle jig, achieved a straight crack front while maintaining the fracture toughness value. The authors concluded that these new techniques are superior to that recommended in ISO 15,653.