Fatigue Properties of Fillet Welded Joints on Piping System

• Published in: QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY Vol. 11; no. 1; pp. 180 - 185
• Main Authors: Nakano, Kouichi, Anzai, Toshio, Kai, Yoshimi
• Format: Journal Article
• Language: Japanese
• Published: JAPAN WELDING SOCIETY 1993
• Subjects: critical size; fatigue; fillet; GTAW; ilmenite; low hydrogen; piping; SMAW; socket; weld
• DOI: 10.2207/qjjws.11.180
• ISSN: 0288-4771

Fatigue tests have been performed on fillet welded joints between piping and sockets so as to investigate the effective factors such as welding methods and leg length of welds. The used materials were structural steel (S25C) and carbon steel pipe for pressure service (STPG38). The applied welding methods were GTAW and SMAW. Two types of covered electrodes were ued like as low hydrogen type and ilmenite type for SMAW. The following conclusions are obtained. (1) As a matter of course, the fatigue strength of the joints by GTAW was higher than that of the joints by SMAW. And the fatigue strength of the joints by low hydrogen type covered electrode was higher than that of the joints by ilmenite type. (2) The critical size S/T (S: leg length, T: base metal thickness) was about 1.2. (3) In case the maximum tensile stress of the welded joints exceeds 147 MPa, it is better to select butt joints rather than fillet jonts.