Exploratory Development of Improved Cutting Tools for Titanium.

摘要

Substoichiometric WC-Ni sintered carbide cutting tools, optionally doped with small quantities of selected carbonitrides and carbides for grain size control, show significantly improved resistance to localized crater wear over conventional C-2 and C-3 grade carbides in turning Ti6Al4V alloy, at about equivalent flank wear resistance. The best performing alloys are those with a dual grain structure of respectively, 1 to 2 micrometers and 6 to 10 micrometers tungsten carbide, binder contents between 16 and 9 percent by weight, and carbon deficiencies corresponding closely to the borderline of eta-carbide formation. The alloys can be prepared substoichiometric in bulk or by controlled surface depletion of carbon by exposure to reducing atmospheres. Improvements achieved with cobalt-bonded tools of similar stoichiometries were less than with the nickel-bonded tools.