| Abstract | In this study, the viability of thick-gauge section assembly for hydroelectric turbine manufacture was considered by electron beam welding CA6NM martensitic stainless steel, a widely utilized hydro-turbine cast material. Particularly, bead-on-plate trials on 60 mm-thick CA6NM plates were carried out using a 42 kW high vacuum electron beam welding system. The influence of the heat input, beam position, beam oscillation (XSF-YSF), and in-situ pre-heating conditions on the characteristics of the weldments, such as the bead geometry, weld integrity, fusion zone and HAZ microstructures and hardness were evaluated. A relationship between the welding parameters and the resulting depth of penetration was established. A methodology for in-situ heating of the thick-gauge section prior to welding was developed and evaluated for reducing welding defects in CA6NM. |
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