| 摘要 |
PURPOSE:To produce efficiently a moving blade that has a shield and is excellent in strength at the joined section, by joining an erosion shield and a shield support using the diffusion bonding technique, and welding the shield support and a blade base. CONSTITUTION:The last stage moving blades of a steam turbine will be wasted due to cavitation erosion by high speed impingement of condensed water droplets contained in steam. To overcome this, an erosion shield (a) of a stellite alloy containing about 50% Co that is excellent in resistance to cavitation erosion is joined to a 12-Cr base steel of the blade base (b) at the forward edge of the forward end section of the blade where wastage will occur more thereby protecting the forward edge. To join the shield (a) to the blade base (b), first the shield (a) is joined to the shield support (c) by the diffusion bonding technique, and then the shield support (c) and the blade base (b) are welded. Thus, an article that is high in strength at the joined section can be obtained highly efficiently. |
