Testing Hyper-Carbide limits: Turning Performance

When SRL Nano Corp. developed carbide-grade tools that use a patented binder material with a melting threshold similar to that of carbide—about 2,870º C—naturally the Rosemead, Calif., company dubbed the new material Hyper-Carbide. And once you view the video below that captures a series of cutting tool tests, it’s easy to see why.

By comparison, carbide tools that use cobalt as the binder melt at about 1,495º C because that is the heat threshold for cobalt. And at 2,000 HV and harder, Hyper-Carbide is about three times harder than cobalt binder-style carbide. That makes Hyper-Carbide tools suitable for machining hardened steels, hardened high-temperature alloys, compacted graphite iron and even carbide, according to SRL.

Scott Gore, a technical support specialist with Setech Inc., Murfreesboro, Tenn., provides the commentary for a series of Hyper-Carbide cutting tool tests captured on video. Presented as a Web-based supplement to an Industry News item in Cutting Tool Engineering’s December 2010 issue, the brief report includes video supplied by Setech and SRL Nano Corp., a California company specializing in high-strength cutting materials.

The hardness of the material, however, also makes it more brittle than other carbide grades, so obtaining sufficient corner strength on a cutting tool is difficult. SRL said Hyper-Carbide is tougher than cemented carbide when both materials have the same hardness, and the average tranverse rupture strength of one Hyper-Carbide grade is 700 ksi.

SRL experimented with applying K-lands and other edge preparations to the cutting edges, but obtained inconsistent results, noted Scott Gore, who works with SRL on testing applications. “Tools live and die with their corner strength,” he said.

For a solution to this problem, SRL turned to Conicity Technologies, a manufacturer of equipment for creating edge preparations on cutting tools. The Greensburg, Pa., company initially treated the Hyper-Carbide tools like conventional carbide but then changed the parameters to those more typical for edge prepping PCBN and PCD tools, noted Bill R. Shaffer, Conicity’s executive vice president. “I actually have to run the equipment at settings that would destroy both PCBN and PCD, and what I got was a beautifully controlled prep,” he said. “The tool material immediately responded to the increased corner strength.”