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Gas & Steam Turbine

Surface Finishing for Gas & Steam Turbine Applications

Gas and Steam Turbines are critical power generating tools both for powering our day-to-day lives and for critical propulsion applications in the aerospace industry and others.  These devices commonly operate under extremely high loads and speeds, place high performance demands on their components such as gears and airfoils.

REM’s ISF® Process is an isotropic superfinishing technology that has been utilized to polish the surfaces of Gas and Steam Turbine airfoil/compressor blade applications for over thirty years due to its high process reliability/repeatability and its unique process features and benefits.

ISF Processed TurbineFor airfoil and compressor blade applications, the ISF Process has been proven to produce extremely low surface roughness finishes (< 2µin / 0.5 µm ) on milled or shot-peened surfaces while maintaining critical blade geometries including leading edges, trailing edges, blade tips, and dovetails.  The surface texture generated by the ISF Process has been shown to maintain higher levels of cleanliness in operation thereby not only increasing turbine efficiency due to the improved laminar flow properties of the ISF® Surface, but also maintaining it across the thousands of hours of operating life to the turbine.  Due to the unique chemical-mechanical nature of the ISF Process, it has also be shown to have passivating effects on stainless steel alloys resulting in increased resistance to stress corrosion cracking.

For gear applications, the ISF Process is proven increase gear life, especially in the high load and speed operating conditions which are commonly experienced in a turbine generator.  This increase in life is linked to improved load distribution, reduced surface friction, and improved resistance to scuffing.

The ISF Process represents a significant upgrade in process control, repeatability, and final product as compared to standard abrasive tumbling operations and hand/robotic belting operations.  Lastly, the ISF Process has successful been used to repair/refurbish used, lightly damaged power transmission gears and gas/steam turbine compressor blades.

Common Gas & Steam Turbine Applications for the ISF Process:

  • Compressor Blades
  • Hot Section or Hot Side Airfoils
  • Blisks
  • Accessory Drive Gears

Component Benefits for Gas & Steam Turbine Applications:

  • Reduced Friction/Roughness
  • Increased Resistance to Micropitting
  • Increased Resistance to Scuffing
  • Increased Resistance to Contact and Bending Fatigue
  • Increased Part Durability/Reduced Wear
  • Reduced Lubricant/System Operating Temperatures
  • Reduced Vibration and Noise
  • Increased Power Density Allowable/Component Load Carrying Capacity
  • Reduced Lubrication Requirements and Cost (anti-wear additives, etc.)
  • Increased Lubricant Lambda Ratio
  • Increased Fuel Efficiency/Operating Efficiency
  • Increased Average Time Between Maintenance
  • Improved Laminar Flow Properties/Reduced Turbulence
  • Eliminated Break-in Step Requirement
  • Reduced Warranty Maintenance Costs
  • Increased Resistance to Stress Corrosion Cracking
  • Increased Cleanliness during Operation
  • Potential to Refurbish Used Gears/Compressor Blades

Production Benefits for Gas & Steam Turbine Applications:

  • Eliminate Abrasive Tumbling
  • Eliminate Hand Polishing or Robotic Polishing
  • Potential to Reduce Milling Surface Finish Requirements
  • Potential to Eliminate Coating Requirements
  • Potential to Reduce Grinding Surface Finish Requirements

Common Gas & Steam Turbine Alloys REM can Assist with:

  • Standard Gear Steels (ex. SAE 4340, DIN 34CrNiMo6)
  • Specialty Steels (ex. M50/M50 NIL, SAE 4122-MOD)
  • Stainless Steels (ex. 15-5 PH, 17-4 PH, 300 series, 400 series)
  • Aluminum Alloys
  • Titanium Alloys (ex. Ti 6Al-4V)
  • Nickel-based Superalloys (ex. Inconel® 625, Inconel® 718, Hastelloy® X, JBK-75, NASA HR1)

Common Gas & Steam Turbine Component Forming Methods the ISF Process can Improve:

  • Cast
  • Forged
  • Milled

Interested in learning more, ready to start a project, or have an application that you don’t see listed here?  Contact us today to see how we can help solve your surface finishing/polishing needs.