Gate Valve Stem Burnishing – Case Study

Gate Valve Stem Burnishing Case Study

The Challenge

A customer of ours was manufacturing gate valve stems made of Inconel alloy 718 using a Takisawa CNC Lathe. The valve stems were 11.81” (300mm) long, had a diameter of 1” (25.527mm), and required a finish of 16 Ra microinch (0.4 Ra) or better on the main diameter of the stem. Before contacting us, they had to transfer the part to a CNC grinding machine to achieve the required surface finish which was very time consuming.

Turning Operation prior to burnishing:

  • Speed: 450 RPM
  • Feed: 0.004”/rev (0.1mm/rev)
  • Finish achieved: 48 Ra microinch (1.2 Ra)

Our Solution

After we assessed their operation, we suggested they use a S2327-00M Single Roll Burnishing Tool made by Elliott Tool Technologies. Here were the statistics after using this burnishing tool:

  • Speed: 450 RPM
  • Feed: 0.002”/rev (0.05mm/rev)
  • Radial load: 0.04” (1mm)
  • Finish achieved: 6-8 Ra microinch (0.16-0.20 Ra)

Final Results

The single roll burnishing tool achieved a finish of 6-8 Ra microinch (0.16-0.20 Ra). It also allowed the shaft to be finished in one machine, eliminating the costly grinding process. They also saved 30 minutes on each part they made using our burnishing solution.