Case Study: Burnishing Inconel Valve Body

Summary Of Results


A customer of ours was trying to achieve a required surface finish by boring but could only maintain 16-20 Ra (0.4 – 0.5 Ra µm) 
Material: Inconel 718
Diameter:  1.00 in (25.40mm)
Machine: Nakamura 5-axis mill-turn
Part: Valve Body
Finish Required: 8 Ra microinch (0.2 Ra µm)
Part preparation:  Single point boring tool
Inconel valve body burnished with a roller burnishing tool


We recommended they use a multi-roll ID burnishing tools made by Elliott Tool Technologies. Here is the data for this burnishing operation:
Speed: 500 RPM
Feed: 0.040”/rev (1.0mm/rev)
Pre-Op: Bored to 60 – 80 Ra (1.5 – 2.0Ra µm) 
ID multi roller burnishing tools grouped together


The multi roll burnishing tool achieved a surface finish of 4-6Ra micro inch which was within the requirement. The manufacturer did not need secondary operations to achieve the required surface finish and cycle time was reduced due to a faster boring cycle. 
Finish Achieved: Less than 8 Ra micro inch (less than 0.4 Ra µm)