Corrosion and wear resistant cemented carbide

Details Corrosion and wear resistant cemented carbide Corrosion and wear resistant cemented carbide

2001-08-03

2003-03-25

Mai, Ngoclan (Department: 1742)

Specialized metallurgical processes, compositions for use therei

Compositions

Consolidated metal powder compositions

Reexamination Certificate

active

06537343

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to chromium carbide-cemented carbide compositions, articles made therefrom and their processing.
2. Background
A chromium carbide (Cr
3
C
2
) nickel based (i.e., greater than 50 w/o Cr
3
C
2
) grade of cemented carbide has been made for many years. However, it has been difficult to control the grain growth of chromium carbide during liquid phase sintering. The chromium carbide grain size of this material is coarse. These coarse grains result in a material having reduced strength, toughness, hardness/abrasion resistance which greatly limits its commercial application. An example of a prior art commercial grade of chromium carbide—nickel is a composition reportedly having 85 w/o chromium carbide 15 w/o nickel, Rockwell A hardness of 88.5, density of 7.00 g/cc, transverse rupture strength of 100 ksi (689 N/mm
2
) and A04 porosity. A microstructure of this prior art material is shown in FIG.
1
.
It would, therefore, be desirable to produce a chromium carbide based (i.e., at least 50 w/o Cr
3
C
2
) cemented carbide composition having a combination of high corrosion resistance with high strength, toughness and hardness/abrasion resistance.
SUMMARY OF THE INVENTION
In accordance with the present invention, an article of manufacture is provided having a chromium carbide based composition having a combination of excellent corrosion resistance and good wear resistance, strength and toughness.
In accordance with the present invention, the chromium carbide based composition has chromium carbide grains, having an average grain size of less than 10 &mgr;m disbursed in and cemented together by a nickel and/or chromium based binder.
Preferably, the average grain size of the chromium carbide grains are less than 8 &mgr;m and more preferably less than 5 &mgr;m.
Preferably, the chromium carbide based composition has a porosity rating of A02 or better.
Preferably, the chromium carbide composition has an average transverse rupture strength of at least 875 N/mm
2
, more preferably at least 1000 N/mm
2
, and most preferably at least 1075 N/mm
2
.
A particularly preferred composition in accordance with the present invention has a nickel content of 13 to 17 weight percent and a chromium carbide content of 83 to 87 weight percent, with a chromium carbide average grain size of less than 8 &mgr;m, a porosity rating of A02 or better, a Rockwell A hardness of at least 89.5, and an average transverse rupture strength of at least 1075 N/mm
2
.
These and other aspects of the invention will become more apparent upon consideration of the drawings, which are briefly described below, in conjunction with the Detailed Description of the Invention.


REFERENCES:
patent: 2753621 (1956-07-01), Wellborn
patent: 3532492 (1970-10-01), Powell
patent: 3552937 (1971-01-01), Mito et al.
patent: 4173457 (1979-11-01), Smith
patent: 5778301 (1998-07-01), Hong
patent: 5833838 (1998-11-01), Heyse et al.
patent: 6258256 (2001-07-01), Heyse et al.
patent: 1202844 (1970-08-01), None
“Kennametal Specialty Carbide Products” Brochure, Kennametal Inc., A93-35- (10) A5, 1993, 15 pages.
ASM Handbook, vol. 3, Alloy Phase Diagrams, 1992, ASM International, Materials Park, Ohio, 3 pages.
Metals Handbook Ninth Edition, vol. 13, Corrosion, 15 pages.
Brookes, Kenneth J A, CEng FIm FJI, World Directory and Handbook of Hardmetals, Fourth Edition, International Carbide Data, 1987, 4 pages.
Brookes, Kenneth J A, CEng FIM FCIJ, World Directory and Handbook of Hardmetals and Hard Materials Fifth Edition, International Carbide Data, 1992, 5 pages.
Carmet PCC Structurals, Inc., Grade Conversion Properties, 1999, 3 pages, at www.carmetcarbide.com/grade_conversion. htm.
Carmet PCC Structurals, Inc., Carmet Quality Products, 3 pages, at www. carmetcarbide.com/products.htm.
Schwarzkopf, Dr. Paul, and Kieffer, Dr. Richard, “Cemented Carbides,” The MacMillan Company, 1960, 6 pages.
General Carbide Corporation “Get Your Nickel's Worth,” “A Guide to Carbide Grade Selection,” 4 pages, at www.generalcarbide.com/products
ickel_performs.
Carmet PCC Structurals, Inc., Material Property Data Grade CA-815,) 1 page.
Kny, E. and Schmid, L. (Metallwerk Plansee Gesellschaft, Reutte, Austria, New Hardmetal Alloys with Improved Erosion and Corrosion Resistance, R&HM Sep. 1987, 4 pages.

Affiliated with

Also associated with

Rating

Corrosion and wear resistant cemented carbide does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Corrosion and wear resistant cemented carbide, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Corrosion and wear resistant cemented carbide will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3074752