Effect of welding structure on high-cycle and low-cycle fatigue properties for MIG welded A5083 aluminum alloys at cryogenic temperatures

• Published in: Cryogenics (Guildford) Vol. 41; no. 7; pp. 475 - 483
• Main Authors: Yuri, Tetsumi, Ogata, Toshio, Saito, Masahiro, Hirayama, Yoshiaki
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-07-2001; Elsevier
• Subjects: Aluminum alloy; Applied sciences; Crack initiation; Crack propagation; Cryogenic temperatures; Cryogenics; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fatigue of materials; Fatigue testing; High-cycle fatigue property; Liquefied natural gas; Low-cycle fatigue property; MIG weld; Refrigerating engineering. Cryogenics. Food conservation; Stress analysis; Tanks (containers); Tensile strength; Welding structure; Welds; Cryogenic temperatures; High-cycle fatigue property; Welding structure; Low-cycle fatigue property; Aluminum alloy; MIG weld; Welded joint; Fatigue strength; Cryogenics; Mechanical properties; Cryogenic storage; Aluminium alloy; Liquid hydrogen; MIG welding; Cryogenic temperature; Low cycle fatigue; Storage tank
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/S0011-2275(01)00100-X

High-cycle and low-cycle fatigue properties of aluminum alloy A5083 base and A5183 weld metals and the effect of welding structure on their fatigue properties have been investigated at cryogenic temperatures in order to evaluate the long-life reliability and safety of the structural materials used in liquid hydrogen supertankers and storage tanks and to develop a welding process for these applications. In the high-cycle fatigue tests, the S–N curves of A5083 base and A5183 weld metals shifted to higher stress levels, i.e., the longer life side at lower test temperatures. The ratios of 10
6-cycles fatigue strength (FS) to tensile strength (TS) for A5183 weld metals were slightly lower than those of A5083 base metals at each test temperature. Although the ratios of FS to TS for austenitic stainless steels weld metals at 4 K decreased substantially to about 0.4, that of A5183 weld metal was 0.65 even at 4 K and it indicated an excellent high-cycle fatigue property. Fatigue crack initiation sites in A5183 weld metals were occurred from the blowholes if the blowholes were located in the vicinity of the specimen surfaces. However, effects of the blowholes on high-cycle fatigue properties are not clear or significant. In the low-cycle fatigue tests, the fatigue lives of A5183 weld metals were slightly shorter than those of A5083 base metals at cryogenic temperatures. However, the fatigue lives of A5183 weld metals at 4 K were superior to that of conventional A5083 weld metals. The deterioration of low-cycle fatigue properties of A5183 weld metals at cryogenic temperatures were due to the intergranular fracture surface observed in fatigue crack propagation regions.