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Steam turbines are large rotating machinery, with many blades, that convert steam power into rotary motion. In the interwar period, 1918 - 1939, they were used principally in power plants and naval propulsion, as far as I know.

How were they typically manufactured during this time? I'm especially interested in whether the blades were cast into molds, or else had to be forged and shaped by a machine. This has huge implications for cost.

Note I have a related yet much more specific question about steam turbine blade alloy.

  • Reasoning from first principles, the low volume , absence of super alloys (only invented in the 1940's) , and demanding manufacturing standards leads me to expect custom manual manufacturing as the norm. – Pieter Geerkens Aug 7 '18 at 20:54
  • I expect like today, some were cast and some are forged. Especially for gas turbines. Steam turbine are likely more often forged. They are often 13% Cr stainless, while gas turbines use various alloys. Not counting the carbon fiber , etc. used in gas turbine fan blades. If cast , it is with an shell or investment mold ; A one use mold made around a wax or plastic pattern that is burned out. Casting also adds the possibility of single crystal/grain , longitudinal grains, and cooling holes the length of the blade ( gas turbine hot section). – blacksmith37 Aug 8 '18 at 3:17
  • @blacksmith37 Yeah but do you know if that was done in the 1930's, or is it just more modern methods? Especially the 13% Cr, that would be very important to know what time period. I understand steam turbines operate at lower temps than gas turbines, so they don't need to be the superalloys of today, but it's still important to know the alloy. – DrZ214 Aug 8 '18 at 6:35
  • Steam turbines likely did and do also use low alloy and .carbon steels. GE in particular uses 13 Cr in steam for corrosion resistance because of CO2 in the steam. A little CO2 in clean water/steam makes it acidic. I never examined blades from the 30's. – blacksmith37 Aug 9 '18 at 3:37

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