Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3865585 A
Publication typeGrant
Publication dateFeb 11, 1975
Filing dateMay 22, 1973
Priority dateMay 26, 1972
Also published asCA993689A1, DE2225577A1, DE2225577B2, DE2225577C3
Publication numberUS 3865585 A, US 3865585A, US-A-3865585, US3865585 A, US3865585A
InventorsRademacher Leo
Original AssigneeWitten Edelstahl
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Cobalt chromium based alloy
US 3865585 A
Abstract
A cobalt/chromium based alloy suitable for use in making dental prostheses and surgical implants, and also for use in making machine parts which are subject to severe corrosive conditions and mechanical loads at high temperatures, comprises by weight, 26 percent to 31 percent chromium, from 4 percent to 6.5 percent molybdenum, up to 2 percent silicon, up to 6 percent maganese, up to 1 percent iron, up to 0.5 percent boron, up to 0.5 percent carbon, from 0.15 percent to 0.5 percent nitrogen, and the remainder cobalt except for impurities, the sum of the carbon and nitrogen contents not exceeding 0.7 percent.
Images(3)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent Rademacher Feb. 11, 1975 [54] COBALT CHROMIUM BASED ALLOY 2,381,459 8/1945 Merrick 75/171 3,606,615 9 I97] R d' t l. 75 HI Invent: Rademacher, w'tten'Heven 3,758,299 9i1973 Eh nis e t ..75i171 Germany [73] Assignee: Edelstahlwerk Witten Prim ry ExaminerR. Dean Aktiengesellschaft, Witten, Germany A rn y, Ag n or Fi -T wn, M eady and 221 Filed: May 22, 1973 Stanger [21] Appl. No.: 362,867 [57] ABSTRACT A cobalt/chromium based alloy suitable for use in [30] Foreign Application Priority Data making dental prostheses and surgical implants, and May 26, 1972 Germany 2225577 for in making machine Parts which are subject to severe corrosive conditions and mechanical loads at 52] us. c1 75/171, 3/1, 32/2, high temperatures, comprises by Weight 26 Percent to 32/10 A 31 percent chromium, from 4 percent to 6.5 percent 51 1m. 01 C22c 19/00 molybdenum "P to 2 Permt Silicon, "P to 6 P 581 Field of Search 75/171, 170; 148/32, 32.5; maganese "P 1 Percem P 05 Percent 3/1; 32/], 2 10 A ron, up to 0.5 percent carbon, from 0.15 percent to 0.5 percent nitrogen, and the remainder cobalt except [56] References Cited for impurities, the sum of the carbon and nitrogen contents not exceeding 0.7 percent.

10 Claims, No Drawings 1 COBALT ,CHROMIUM BASED ALLOY This invention relates to cobalt/chromium based alloys suitable for use in making dental prostheses structures and surgical implants.

Cobalt/chromium alloys are used in machinery construction predominantly for making components which are subjected to severe corrosive conditions and me chanical loadings at high temperatures. They are however equally well known in surgery for the making of implants and in dentistry for making prosthetic struc tures.

In these medical fields, alloys which, in addition to cobalt as the basic element, also contain by weight from 26 percent to 31 percent chromium, from 4 percent to 6.5 percent molybdenum, up to 1 percent each of silicon, manganese and iron, and from 0.3 percent to 0.5 percent carbon, are of particular importance. In addition, alloys are also used which, principally owing to the cost of cobalt content, contain instead up to 20 percent nickel. These may also have the silicon and manganese contents raised up to 6 percent, and may also be provided with additions of copper, aluminium, titanium, niobium, vanadium, zirconium, tantalum, beryllium and boron, either individually or in combination.

The use of these alloys in surgery and dentistry is based upon the fact that they are resistant to the corrosive conditions existing in the body and in the oral cavity; are easy to cast to the frequently very complicated shapes required; are easy to work, and possess a high modulus of elasticity and high strength and hardness. The published values are: for the modulus of elasticity an average of 220,000 N/mm and depending upon the strength of the alloy, .for the technical elastic limit (0.01 limit) approximately 390 and 440 N/mm respectively, for the 0.2-limit approximately 600 and 625 N/mm respectively, and for the tensile strength approximately 880 and 910 N/mm respectively. Values for the hardness are 340 and 380 Brinell hardness respectively.

A disadvantage of these cobalt/chromium alloys is their low capacity for deformation, that is low ductility. This is usually expressed by the elongation at rupture. The published values vary considerably but are predominantly in a range from 2 percent to 6 percent. The highest value published is 8 percent. Because of these low elongation values for the alloys, severe limits are set on the plastic deformations which can be applied to articles made from them, for example straightening operations on the holding braces of dental prosthetic structures, if the risk of breakage is to be avoided.

For this reason, titanium-containing alloys with a cobalt base having improved capacity for deformation for the same or an increased strength have been developed. These alloys contain, by weight, in addition to cobalt, from percent to percent chromium, from 5 percent to percent nickel, up to 3 percent molybdenum, up to 1 percent carbon, silicon, manganese, aluminium and/or iron and from 4 percent to 10 percent titanium. The published values of their elastic limit range, for the 0.2-limit from approximately 560 to 800 N/mm for the tensile strength from approximately 845 to 1,110 N/mm for the elongation from 10 to 12.7 percent and for the Brinell hardness from 330 to 380 kp/mm Due to the very high affinity of titanium for oxygen, these alloys suffer from the substantial disadvantage that they must be melted under vacuum or under a protective gas, and that, when manufacturing prostheses and implants, they can be melted only by using an acetylene-oxygen-burner with a flame adjusted absolutely to neutral, and not by the high frequency induction heat sources which are also frequently used.

Finally, alloys having a cobalt/chromium base are also known which, in addition to cobalt, contain, by

weight, from 20 percent to 28 percent chromium, from 10 percent to 20 percent nickel, from 3.7 percent to 4.1 percent molybdenum, and from 0.18 percent to 0.22 percent carbon. As a result of this narrow limitation of the molybdenum and carbon contents, the e1ongation is raised to from 10 percent to 14.5 percent. This advantage is however offset by the substantial disadvantage of an appreciable drop in the elastic limit. The values published are, for the 0.l-limit from 375 to 415 N/mm for the tensile strength from 595 to 715 N/mm and for the Diamond Pyramid hardness from 270 to 310 kp/mm It is the object of this invention to provide an alloy which avoids the disadvantages mentioned above while at the same time exhibiting an adequate or even an improved ductility.

To this end, according to this invention, an alloy comprises, by weight, from 26 percent to 31 percent chromium, from 4 percent to 6.5 percent molybdenum, up to 2 percent, and preferably only up to 1.5 percent silicon, up to 6 percent and preferably only up to 3 percent manganese, up to 1 percent iron, up to 0.5 percent boron, up to 0.5 percent carbon and from 0.15 percent to 0.5 percent nitrogen the remainder cobalt except for impurities, and the sum of the carbon and nitrogen contents not exceeding 0.7 percent The nitrogen content is preferably from 0.20 percent to 0.35 percent, or advantageously up to a maximum of only 0.30 percent.

For some applications, both the silicon and the manganese contents should not exceed 1 percent each. A boron content of preferably from 0.01 percent to 0.15 percent, is advantageous.

Examples of alloys in accordance with the invention are set out in Table 1. Table 11 gives the associated mechanical properties.

Table I Chemical Composition (/0 by Weight) Example C N (C N) Si Mn Co Cr Mo B 3. Table ll Mechanical Properties 0.2- Tensile Elongation Hardness Elastic Strength HV 30 Example limit (Nlmm (N/mm") (7:) (kg/mm) 1 580 735 8.2 3 l6 2 565 795 l4.6 31 l 3 570 845 l7.l 308 4 675 lOOO I20 327 5 685 1005 12.0 316 6 655 960 8.3 326 7 655 940 10.9 332 8 635 895 7.1 339 9 725 1010 8.2 328 .ness is nevertheless somewhat reduced. This suggests that the increase in the tensile strength values in the tensile test is a direct result of the improved deformability. From a comparison of Examples 7 and 9 with Example 8, it is apparent that in the total content of carbon and nitrogen, the carbon should preferably constitute the smaller component and should preferably not exceed approximately 0.2 percent.

In Examples 4 to 6 and 9, the manganese content has been raised to approximately 3 percent, in order to increase the dissolving capacity of the alloys for nitrogen. An addition of boron improves the capacity for casting (Examples 5 and 6). The mechanical properties are not in any way thereby adversely affected.

I claim:

1. An alloy consisting essentially of from 26 percent to 3l percent chromium, from 4 percent to 6.5 percent molybdenum, up'to 2 percent silicon, up to 6 percent manganese, up to 1 percent iron, up to 0.5 percent boron, up to 0.5 percent carbon, from 0. [5 percent to 0.5 percent nitrogen, with the ,balance being cobalt and impurities, the sum of said carbon content and said nitrogen content not exceeding 0.7 percent.

2. An alloy as claimed in claim 1, wherein said silicon content is no more than 1.5 percent.

3. An alloy as claimed in claim 1, wherein said manganese content is no more than 3 percent.

4. An alloy as claimed in claim 1, wherein said nitrogen content is from 0.2 percent to 0.35 percent.

5. An alloy as claimed in claim 1, wherein said carbon content is no more than 0.2 percent.

6. An alloy as claimed in claim 1, wherein said silicon content and said maganese content are each no more than 1 percent.

7. An alloy as claimed in claim 1, wherein said boron content is from 0.01 percent to 0.15 percent.

8. A dental prosthesis made from an alloy as claimed in claim 1.

9. A surgical implant made from an alloy as claimed in claim 1.

10. A machine component made from an alloy as claimed in claim 1.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2165849 *May 23, 1939Jul 11, 1939Joel Grossman CornellDental casting alloy
US2381459 *Dec 10, 1941Aug 7, 1945Austenal Lab IncTurbine bucket for exhaust turbine superchargers
US3606615 *Apr 21, 1970Sep 21, 1971Krupp GmbhTooth prostheses and surgical implants
US3758299 *Mar 10, 1971Sep 11, 1973Int Nickel CoChromium nickel alloys and articles and parts made therefrom
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4116724 *May 10, 1977Sep 26, 1978Fried. Krupp Gesellschaft Mit Beschrankter HaftungMethod of heat treating cobalt-chromium-molybdenum based alloy and product
US4668290 *Aug 13, 1985May 26, 1987Pfizer Hospital Products Group Inc.Dispersion strengthened cobalt-chromium-molybdenum alloy produced by gas atomization
US4714468 *Jan 27, 1987Dec 22, 1987Pfizer Hospital Products Group Inc.Prosthesis formed from dispersion strengthened cobalt-chromium-molybdenum alloy produced by gas atomization
US4728495 *Mar 20, 1986Mar 1, 1988Thyssen Edelstahlwerke AgRemovable dental appliances
US5002731 *Apr 17, 1989Mar 26, 1991Haynes International, Inc.Carbon, nitrogen, tungsten, chromium, and molybdenum
US5462575 *Dec 23, 1993Oct 31, 1995Crs Holding, Inc.Consolidating powdered alloy charge having controlled amounts of carbon and nitrogen to produce article with high strength, hardness, ductility, corrosion resistance
US5904720 *Aug 12, 1997May 18, 1999Johnson & Johnson Professional, Inc.Cobalt-chromium alloy
US6053729 *Mar 2, 1998Apr 25, 2000Ortho CorporationUnitary substantially nickel free alloy injection molded orthodontic bracket
US6227849Sep 7, 1999May 8, 2001Ortho Organizers, Inc.Unitary substantially nickel free alloy injection molded orthodontic bracket
US6773520 *Sep 13, 2000Aug 10, 2004University Of North Carolina At CharlotteEnhanced biocompatible implants and alloys
US7166256 *Jun 27, 2003Jan 23, 2007J.P. Winkelstroeter Kgcapable of forming a thin oxide layer guaranteeing adhesion between metallic and ceramic surfaces; is substantially free of rare earth elements and carbon
US7396505 *Aug 27, 2004Jul 8, 2008Diamicron, Inc.Use of CoCrMo to augment biocompatibility in polycrystalline diamond compacts
US7520947May 23, 2003Apr 21, 2009Ati Properties, Inc.Cold working, aging; increase the tensile strength, yield strength, hardness, wear resistance, and fatigue strength; articulating medical implants
US7556763Aug 28, 2004Jul 7, 2009Diamicron, Inc.mixing a carbide of Ti or Nb with TiC, enclosing mixture in a niobium can, pressing it into a spherical component by hot isostatic pressing; superhard
US7569116Feb 9, 2006Aug 4, 2009Nhk Spring Co., Ltd.Co-Cr-Mo-based alloy and production method therefor
US7569176Aug 28, 2004Aug 4, 2009Diamicron, Inc.Hardness; sintering; by-product free; nontoxic
US7588650Mar 18, 2005Sep 15, 2009Hitachi, Ltd.Alloy containing silicon, nickel, carbon, at least a refractory metal which promotes work hardening is selected from molybdenum, niobium, tungsten, tantalum, rhenium, balance is cobalt; having good wear resistance, as well as good ductility due to content of hard particles (e.g. carbide) reduced
US7665898Oct 21, 2008Feb 23, 2010Diamicron, Inc.Bearings, races and components thereof having diamond and other superhard surfaces
US7678325Apr 5, 2006Mar 16, 2010Diamicron, Inc.Use of a metal and Sn as a solvent material for the bulk crystallization and sintering of diamond to produce biocompatbile biomedical devices
US8016889Dec 14, 2007Sep 13, 2011Diamicron, IncArticulating diamond-surfaced spinal implants
US8449991Apr 10, 2009May 28, 2013Dimicron, Inc.Use of SN and pore size control to improve biocompatibility in polycrystalline diamond compacts
US8603181Apr 8, 2010Dec 10, 2013Dimicron, IncUse of Ti and Nb cemented in TiC in prosthetic joints
US8663359Jun 25, 2010Mar 4, 2014Dimicron, Inc.Thick sintered polycrystalline diamond and sintered jewelry
EP1655384A1 *Nov 5, 2005May 10, 2006Cordis CorporationA cobalt-chromium-molybdenum fatigue resistant alloy for intravascular medical devices
EP1698709A1 *Feb 17, 2006Sep 6, 2006Nhk Spring Co.Ltd.Co-Cr-Mo-based alloy and production method therefor
EP2676684A1May 15, 2013Dec 25, 2013Biotronik AGCobalt alloy for medical implants and stent comprising the alloy
EP2676686A1May 15, 2013Dec 25, 2013Biotronik AGStent made of a cobalt alloy
WO2000074637A1 *May 31, 2000Dec 14, 2000Osfix Internat Ltd OyDental implants and method for their coating
Classifications
U.S. Classification420/436, 420/440, 433/207
International ClassificationA61K6/04, C22C19/07, A61K6/02
Cooperative ClassificationA61K6/04, C22C19/07
European ClassificationC22C19/07, A61K6/04