Abstract The subject invention provides a method of treating the working surfaces of high speed steel metal cutting tools to reduce the friction between the surface of the cutting tool and the workpiece and/or the chip and the novel tool produced thereby. The method involves a transformation of the working surface on the steel tool which transformation involves the removal of the multitude of tiny carbide particles that appear in random positions on the working surface. This modified surface layer from which the carbide particles are removed leaves a honeycomb like hole structure where they were, extends to a depth equal to about the average size of carbide particles, at most in the low hundred thousandths of an inch. The removal of this surface layer of carbide particles appears to reduce friction between the active tool surfaces and the workpiece and/or chip is substantially reduced, with consequent reduction in buildup of material on the edge of the tool and reduction of friction of the tool with the chip and/or the workpiece. The process of the invention is advantageous in the surface treatment of high speed steel cutting tools such as twist drills and the like. It is particularly advantageous for the treatment of drills employed to drill holes into soft, gummy metals like aluminum, copper, titanium, and some stainless steels and the like, but is not limited thereto. The high speed steels employed for making the metal-cutting tools herein disclosed comprise a major proportion of iron, containing carbon, and alloying metals known as ''''carbide formers'''' including molybdenum, tungsten, chromium and vanadium. Cobalt may also be present. These alloying elements are suitably proportioned to provide the particular properties desired for a specific tool as is well understood in the art.
A method of surface treating a steel cutting tool having chip engaging surfaces to reduce the friction of said chip-engaging surfaces with the chip, which method comprises subjecting said surfaces to electrolytic treatment with the tool as an anode in the electrolytic bath of substantially equal parts of sodium hydroxide and sodium cyanide in water at a Baume of approximately 16* at the start and at a temperature of approximately 135* to 140*F at a current density of approximately 0.5 to 2 amperes per square inch for a period of from 3 to 10 minutes to remove carbide particles from chip engaging surfaces of the tool.
Claim 2
Dependent Claim
23 words
The method of claim 2 wherein the tool is a twist drill having lands, flutes and a point, said point having cutting edges.
Claim 3
Independent Claim
61 words
The method of smoothing tool marks and removing exposed carbide particles from the working surface of a high speed steel cutting tool containing hard carbide particles exposed at the working surface which comprises subjecting the said working surfaces to electrolysis with the cutting tool serving as an anode in an electrolyte of substantially equal parts of sodium hydroxide and sodium cyanide.
Claim 4
Dependent Claim
115 words
Method of producing a high speed steel twist drill of superior performance in drilling relatively soft, tenacious metals which comprises forming a drill of high speed steel which contains iron and carbon and one or more carbide forming alloying metals and contains resulting carbide particles distributed throughout the same, said drill comprising a shank, a body having flutes, lands, margins, a web, lips and cutting edges, and electrolytically removing exposed carbide particles from the surface of the flutes and cutting edges whereby the resulting twist drill will give superior performance on drilling soft, tough metals by virtue of the reduced friction between the surfaces of the drill and the workpiece and the chips produced therefrom.