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."

Shaffer explained that he applies a 0.0012" waterfall, or oval, edge preparation to direct cutting forces at 15º to 20º angle into the tool. That edge prep reportedly increases corner strength six to 10 times.

With its corner-strengthened tools, SRL began conducting tests earlier in the year and generated postive results. For example, in a test conducted Sept. 23 at Weartech International Inc., Santa Fe Springs, Calif., a 3"-dia. Stellite 6 casting with a hardness of 46 HRC was turned with a grade-SK11 Hyper-Carbide CNG332 insert at a cutting speed of 600 sfm, a 0.004-ipr feed rate and a 0.010" DOC when dry machining, and when a water-soluble coolant was applied.

According to SRL, the insert showed no wear after a 10" length of cut. In contrast, Weartech previously applied a grade-907 CNG4321t carbide insert at 100 sfm, 0.005 ipr and a 0.010" DOC with coolant, and a grade-670 CNG4321t ceramic insert reinforced with silicon-carbide whiskers at 250 sfm, 0.004 ipr and a 0.010" DOC with coolant. These inserts exhibited wear after the same length of cut.

In another test the same day at Accufab Inc., Ontario, Calif., SRL compared its grade-SP17 SNG432 insert to a PCBN insert when turning a 1:-dia., M-2 HSS workpiece hardened to 64 HRC for a 1.25" length of cut. The PCBN tool ran at a cutting speed of 150 to 300 sfm, a feed of 0.002 ipr and a DOC less than 0.020" with coolant. SRL's insert was able to dry turn the material at up to 1,000 sfm, a 0.002-ipr feed and a 0.080" DOC.

Although all the tests have been conducted for continuous cutting, the company plans to do interrupted-cutting tests. Also, the company performed the tests with uncoated tools, but the tool material can be coated with commercially available coatings.

SRL plans to offer its tool material for commercial industrial applications in 2011. For more information, visit the company's Web site for its new material: www.hypercarbide.com.