Effects of Insert Metal on Some Properties of Spheroidal Graphite Cast Iron Welds : Study on Electron Beam Welding of Spheroidal Graphite Cast Iron (Report 2)
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概要
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When butt welding 500 MPa class spheroidal graphite cast iron (FCD500) by EBW (6 kW class), such defects as cracks and porosities tend to occur. In an attempt to prevent them austenitic stainless steel (SUS304) was used as an insert metal and its influence on some room temperature properties of the welds was examined. When the welding condition is such that a wedge-type bead is obtained, a considerable amount of the base metal, i.e. FCD500, is melted and mixed into the fusion zone which consists mainly of the insert metal, resulting in the following various structural changes. Hardness of the fusion zone increases and a fine cell-dendrite structure changes into an irregular-shaped solidification structure. Martensite, eutectic and cementite are formed along the peripheries of the graphite nodules in the fusion zone and the heat-affected zones, increasing local hardness and causing cracks. Carbon and silicon in the fusion zone increase with an increasing number of passes, while manganese, phosphorus, nickel and chromium decrease. Decrease of nickel and chromium is especially remarkable in a 2-pass welding. EPMA, both line and scanning analysis, revealed diffusion layers of chromium along the peripheries of graphite in the fusion zone and heat-affected zones. A strong segregation of silicon was also observed around graphite in the fusion zone. In addition, a remarkable segregation of some elements, mainly deoxidizing elements such as carbon, silicon, manganese or chromium, was observed in the fusion zone.
- 社団法人溶接学会の論文
- 1991-04-01
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関連論文
- Effects of Porosities on Welded Joint Strength of Spheroidal Graphite Cast Iron Welds Using Insert Metals : Study on Electron Beam Welding of Spheroidal Graphite Cast Iron (Report 3)
- Formation Mechanism of Weld Defects of Spheroidal Graphite Cast Iron Welds : Study on Electron Beam Welding of Spheroidal Graphite Cast Iron (Report 1)
- Effects of Insert Metal on Some Properties of Spheroidal Graphite Cast Iron Welds : Study on Electron Beam Welding of Spheroidal Graphite Cast Iron (Report 2)