Twist drilling of Haynes 282 superalloy

Experimental work is presented detailing tool wear and workpiece integrity results when drilling next generation Haynes 282 aeroengine casing material using coated carbide tooling with high pressure (50 bar) cutting fluid. Testing involved variation in cutting speed and feed rate typically used for Ni-based superalloys. At lower combinations of operating parameters, flank wear was generally uniform however extensive wear/fracture of the tool corner chamfer was evident in the majority of tests. Adhered material up to similar to 250 mu m long was observed on all machined surfaces, which increased with worn tooling and at higher operating conditions. Microhardness results showed an increase in hardness (up to 50 HK0.05 above the bulk) within the first 50 mu m. Surface/subsurface microstructural damage consisted of deformed grain boundaries up to a depth of similar to 15 mu m with a discontinuous white layer of up to similar to 6 mu m from the surface. (C) 2012 Published by Elsevier Ltd. Selection and peer-review under responsibility of Prof. E. Brinksmeier