Stock material or miscellaneous articles – All metal or with adjacent metals – Having metal particles
Patent
1992-08-25
1994-05-10
Walsh, Donald P.
Stock material or miscellaneous articles
All metal or with adjacent metals
Having metal particles
428546, 419 38, 419 10, 419 14, 419 15, 419 16, 419 25, B22F 310
Patent
active
053106059
ABSTRACT:
A process for producing a ceramic-metal composite body exhibiting binder enrichment and improved fracture toughness at its surface. The process involves forming a shaped body from a homogeneous mixture of: (a) about 2-15 w/o Co or about 2-12 w/o Ni binder, (b) excess carbon, (c) optionally, 0 to less than 5.0 v/o B-1 carbides, and (d) remainder tungsten carbide. The mixture contains sufficient total carbon to result in an ASTM carbon porosity rating of C06 to C08 at the core of the densified body. The weight ratio of excess carbon to binder is about 0.05:1 to 0.037:1. The shaped body is densified in a vacuum or inert atmosphere at or above about 1300.degree. C. and slow cooled, at least to about 25.degree. below the eutectic temperature. Alternatively, the sintered body may be cooled to a holding temperature at or slightly above the eutectic temperature, isothermally held for at least 1/2 hr, and further cooled to ambient. The core zone of the resulting densified body exhibits an ASTM carbon porosity rating of about C02-C08, while its surface zone exhibits an ASTM carbon porosity rating of about C00. The surface zone has an outer surface layer enriched in binder content to a depth of about 5-200 .mu.m, improving the surface fracture toughness of the body. Sintering temperature and pressure may be tailored to produce efficiently either a tool suitable for coating or a tool suitable for brazing.
REFERENCES:
patent: Re32111 (1986-04-01), Lambert et al.
patent: Re34180 (1993-02-01), Nemeth et al.
patent: 3999953 (1976-12-01), Kolaska et al.
patent: 3999954 (1976-12-01), Kolaska et al.
patent: 4150195 (1979-04-01), Tobioka et al.
patent: 4277283 (1981-07-01), Tobioka et al.
patent: 4497874 (1985-02-01), Hale
patent: 4548786 (1985-10-01), Yohe
patent: 4610931 (1986-09-01), Nemeth et al.
patent: 4830930 (1989-05-01), Taniguchi et al.
patent: 4911989 (1990-03-01), Minoru et al.
ASTM Designation: B 276-86, "Standard Test Method for Apparent Porosity in Cemented Carbides," American Society for Testing and Materials, Philadelphia, Pa.
B. J. Nemeth et al., "The Microstructural Features . . . of the High Edge Strength Kennametal Grade KC850," Proc. 10th Plansee Seminar, 1, Reutte/Tyrol, pp. 613-627 (1981).
G. P. Grab et al., "An Advanced Cobalt-Enriched Grade Designed to Enhance Machining Productivity," High Prod. Machining, V. K. Sarin, Ed., ASM (1985) pp. 113-120.
H. Suzuki et al., "The .beta.-Free Layer Formed near the Surface of Vacuum-Sintered WC-.beta.-Co Alloys Containing Nitrogen," Trans. J. Inst. Met., 22 [11] 758-764 (1981).
H. Tsukada et al., "The Development of a Nitrogen-Contained Cemented Carbide and the Cutting Performance of the Grade A30N . . . ," Sumitomo Elec. Technol. Rev., No. 24 (Jan. 1985).
A. Doi et al., "Thermodynamic Evaluation of Equilibrium Nitrogen Pressure and WC Separation in Ti-W-C-N System Carbonitride," Proc. 11th Plansee Conf., HM8, pp. 825-843 (1985).
M. Schwarzkopf et al., "Kinetics of Compositional Modification of (W,Ti)C-WC-Co Alloy Surfaces," Mat. Sci. Eng., A105/106 (1988) 225-231.
Baldoni, II J. Gary
Bennett Stephen L.
Greaves John N.
Panagos Bill C.
Valenite Inc.
Walsh Donald P.
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