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Publication numberUS3802939 A
Publication typeGrant
Publication dateApr 9, 1974
Filing dateMar 22, 1971
Priority dateMar 22, 1971
Publication numberUS 3802939 A, US 3802939A, US-A-3802939, US3802939 A, US3802939A
InventorsS Ohtani, M Nishigaki
Original AssigneeKobe Steel Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Surface-hardened titanium or zirconium and their alloys and method of processing same
US 3802939 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent 1 1 Ohtani et al.

[ SURFACE-HARDENED TITANIUM OR ZIRCONIUM AND THEIR ALLOYS AND METHOD OF PROCESSING SAME [75] Inventors: Shitoshi-Ohtani, Suita; Minoru Nishigaki, Akashi, both of Japan [73] Assignee: Kobe Steel, Ltd., Fukiai-ku, Kobe,

Japan 221 Filed: Mar. 22, 1971- [21 Appl. No.: 126,630

[52] U.S. Cl 148/133, 29/198, 148/32.5, 148/34, 148/127 [51] Int. Cl. C22f l/l8, B32b 15/00 [58] Field of Search 148/31.5, 32.5, 34, 133,

[56] References Cited V UNITED STATES PATENTS 3,645,803 2/1972 Huber et al 148/127 X 3,560,274 2/1971 Ogden....., 29/198 2,940,163 6/1960 Davies 29/198 X 3,493,353 2/1970 Bergmann et al 29/l98 X .1 3,802,939 I Apr. 9, 1974 2,932,887 4/1960 McCuaiget a1. 29/198 X OTHER, PUBLICATIONS Metallurgio, December 1957, pages 277-282 Metal Selector,- 1963 Edition Reprinted from Oct. 14, 1963 Steel, page S40 Primary E.\'aminerCharles N. Lovell Attorney, Agent, or Firm-Oblon, Fisher, Spivak, Mc- Clelland & Maier 57 ABSTRACT Surface-hardened pure titanium or pure zirconium,

titanium-base alloys, or zirconium-base alloys having thereon, and aging said coated alloyat temperatures of-200-600C. Y 12 Claims, 2 Drawing Figures HARDNESS (Hv) ATENTEBAPR 9 974 AFTER E 8 Lu 5 5 I L 6 i 2 J BASE METAL DEPOSIT w o 600- E a AFTER AGING 50c 40W AFTER SOLUTION TREATMENT 2 IOO- INVENTORS SHITOSHI OHTANI MINORU NISHIGAKI I ("Q") 6 fl 2 J @rg g .;'$,/o%

BASE METAL DEPOSIT SURFACE ATTORNEYS 1 SURFACE-HARDENED TITANIUM OR ZIRCONIUM AND THEIR ALLOYS AND METHOD OF PROCESSING SAME BACKGROUND OF THE INVENTION 1. Field Of Invention This invention relates to surface-hardened titanium, zirconium or their alloys and to a method of preparing same. Moreparticularly, this invention relates to surface-hardened, pure'titanium, pure zirconium, titanium-base alloys, or zirconium-base alloys, and to a method of surface-hardening such metals.

2. Description Of The Prior Art Generally, titanium and zirconium have superior corrosion resistance in comparison with the other metals,

and accordingly they are broadly used in the chemical 800C. to form a solid solution of nitrides and a diffusion layer. Usually, the titanium or zirconium is contact-treated with a nitriding gas at temperatures of from 8009 OOC. so as to harden their surfaces. Although this method has been commercially applied, since the surface-hardened layer obtained is extremely thin, its 4 endurance period is very short, in spite of the very complicated treating operation. Other priorart methods also have similar disadvantages, and hence are similarly ineffective for many commercial applications.

SUMMARY OF THE INVENTION Accordingly, one object'of the present invention is to eliminate the aforementioned disadvantages of conventional methods and to provide a novel and improved Briefly, these and other objects are attained in one aspect of the present invention wherein surfacehardened pure titanium or zirconium is provided by a process which comprises coating a metastable beta alloy layer of a titanium or zirconium-base metal onto said pure metal, and agingsaid coating to give a hardness of at least 400 Vickers hardness or above. The

' aforementioned metastable beta alloys may be any of the Ti(Zr)-Mo type, Ti(Zr)-V type, Ti(Zr)-Fe type, Ti(Zr)-Cr type, Ti(Zr)-Mn type, Ti(Zr)-Nb type, Ti(Zr)-Ta, and multi-element type alloys containing three or more elements of the aforesaid two-element type alloys.

According to another aspect of the present invention,

surface-hardened titanium-base or zirconium-base alloys are provided by a process which comprises coating a metastable beta alloy' layer of a titanium or zirconium-base metal onto said alloy and aging as above. The

aforesaid titanium-base alloys may be of a Ti-6Al-4V type, Ti-5Al-2Cr-lFe type, Ti-5Al-2.5Sn type, Ti-

0.2Pd type, Ti-8Mn type, Ti-8Al-lMo-lV type, Ti6Al- 6V-2 Sn type,-Ti-4Al-3Mo-1V type, Ti-2Cu type, Ti- 2Al-2Mn type, Ti-2.25Al-llSn-5Zr-l-Mo-O.1Si type, Ti-5Al-5Sn-5Zr type, and the like.

The'aforesaid zirconium-base alloys may be Zircaloy' 2', Zircaloy-4, and the like.

According to afurth er aspect of this invention, there is provided a method of hardening the surface of pure titanium, pure zirconium, or titanium-base or zirconium-base alloys, which comprises the steps of coating a metastable beta alloy of a titanium-base or zirconiumbase metal thereon and aging said coated alloy at temperatures of 200-600C. Thus, a surface-hardened layer may be very effectively formed on the surface of the metal to be treated according to this invention, in various thickness suitable for the intended purpose.

In the method of this invention, if the metastable beta alloy of the titanium-base or zirconium-base metalis aged at low temperatures of 200600C., the beta phase is decomposed to precipitate the alpha phase or its intermediate phase, i.e., omega phase, and the alloy is extremely hardened. This fact is utilized in this invention in such a manner that the metastable beta phase alloy of this type is coated in advance on the surface of the metal to be treated, and then the coated surface is aged at a low temperature region so as to harden only the surface layer, providing a titanium or zirconium product.

The coating of the metastable .beta phase alloy may be provided on the surface of the metal to be treated, for example, by diffusion welding or explosive pressure welding. The most effective and simplest method, however, will often be deposit welding. In this case, since the metastable beta phase alloy to be deposited on the metal surface to be treated is common to the metal to be treated in the base metal, the welded portion will have no possibility of becoming fragile by metallurgical reaction.

In the method of this invention, the coated surface is aged in the temperature range of 200-600C. for a suitable period of time in the range of 5 minutes to 20 BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention will be readily obtained as the same becomes better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings, wherein:

FIGS. 1 and 2 are graphical representations of the hardness distribution obtained from a titanium-base alloy treated in accordance with the'present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference is now made to FIG. 1, which shows the hardness distribution obtained by the method of this invention. Pure titanium plate was prepared as the base metal to be treated. Ti- 1 5Mo-5Zr type alloy was deposited by TIG welding on the surface of the pure titanium plate, which was then held in aging treatment for six hours at 450C. Thus, as shown in FIG. 1, a surfacehardened layer having sufficiently high hardness could be obtained.

Referring now to FIG. 2, which also shows the hardness distribution obtained by the method of this invention, a titanium-base alloy plate of the Ti-5Al-2Cr-1Fe type was prepared as the'base metal to be treated. This alloy was also deposited in a manner similar to the method described above with reference to FIG. 1. The deposited alloy was then subjected to solution treatment at a temperature of 800C. for 2 hours, cooled by water, age treated at a temperature of 450C. for 6 hours, and finally cooled by air. Thus, as shown in FIG. 2, a surface-hardened layer having sufficiently high hardness could also be obtained.

It will be understood from the foregoing description that the surface-hardened pure titanium, pure zirconium, or titanium-base or zirconium-base alloys of this invention have a coating of a metastable beta alloy layer of a titanium or zirconium-base metal which has been aged to a sufficienthardness. The thickness of the surface-hardened layer may be selected in accordance with the intended use. Furthermore, since this layer before the aging treatment is relatively soft, as seen from the graphs shown in the drawings, it is possible to easily work the metai, such as by cutting it or the like, even after the metal is coated, and thereafter age the coating to form the hardened surface. Thus, the method of this invention is particularly adapted for producing agitator blades, valves, bushings, etc.

It should also be understood that since the method of this invention forms an aged coating of a metastable beta phase alloy of the same type of metal as that to be treated, the thickness of the surface-hardened layer may be suitably selected to suit the desired product. It is also possible to work the metal to any shape, due to the aforementioned effects.

It will be appreciated that, while the foregoing disclosure relates only to preferred embodiments of the invention for preparing surface-hardened pure titanium or zirconium, or titanium-base or zirconium-base alloys, numerous modifications or alterations will be apparent to those skilled in the art without departing from the spirit and scopeof the invention as set forth in the appended .claims.

What is claimed as new and intended to be secured by letters patent of the United States is:

l. A titanium or titanium base alloy having a deposited Ti metastable beta alloy layer thereon, said deposited layer being in an age hardened condition and having a hardness of at least 400 Vickers wherein said titanium base alloy is selected from the group consistingof T i-6Al-4V, Ti-SAl-ZCr-lFe, Ti-5Al-2.5Sn, Ti-0.2Pd, Ti-BMn, Ti-8Al-Mo-1V, Ti-6Al-6V-2Sn, Ti-4AI'73MO- 1V, Ti-2Cu, Ti-2Al-2Mn, Ti-2.25Al-l1Sn-5Zr-lMohaving a hardness ofatleast 400 Vickers, wherein said zirconium base alloy is selected from the group consisting of zircaloy-Z and zircaloy-4 and wherein said metastable beta alloy is selected from the group consisting of Zr-Mo, Zr-V, Zr-Fe, Zr-Cr, Zr-Mn, Zr-Nb and Zr- Ta, and alloys containing three or more elements of the aforesaid two element alloys.

3. The titanium or titanium base alloy of claim 1, wherein said age hardening was conducted at a temperature of from 200 600C.

4. The zirconium or zirconium base alloy of claim 2, wherein said age hardening was conducted at a temperature of from 200 600C.

5. A method of hardening the surface of a titanium or titanium base alloy which comprises depositing a layer of a Ti metastable beta alloy onto the surface of said titanium or titanium base alloy, solution heat treating, quenching, and aging said alloy layer at temperatures of 200 600C. for a period of 5 minutes to 20 hours to a Vickers hardness of at least 400, wherein said titanium base alloy is selected from the group consisting of Ti-6Al-4V, Ti-5Al-2Cr-1Fe, Ti-5Al-2.5Sn, Ti-0.2Pd, Ti-8Mn, Ti-8Al-Mo-IV, Ti-6Al-6V-2Sn, Ti- 4Al-3Mo-1V, Ti-ZCu, Ti-2Al-2Mn, Ti-2.25Al-l lSn- 5Zr-lMo-0.1Si, and Ti-5Al-5Sn-5Zr and wherein said metastable beta alloy is selected from the group consisting of Ti-Mo, Ti-V, Ti-Fe, Ti-Cr, Ti-Mn, Ti-Nb, Ti-Ta and alloys containing three or more elements of the aforesaid two element alloys.

6. A method of hardening the surface of a zirconium or zirconium base alloy which comprises:

depositing'a layer of a Zr metastable beta alloy onto the surface of said zirconium or zirconium base alloy, solution heat treating, quenching, and aging said alloy at temperatures of 200 600C. for a period of 5 minutes to 20 hours to a Vickers hardness of at least 400, wherein said zirconium base alloy is selected from the group consisting of zircaloy-2 and zircaloy-4 and wherein said metastable beta alloy is selected from the group consisting of Zr- Mo, Zr-V, Zr-Fe, Zr-Cr, Zr-Mn, Zr-Nb and Zr-Ta, and alloys containing three or more elements of the aforesaid two element alloys.

7. The method of claim 6, wherein said metastable beta alloy is formed by diffusion welding.

'8. The method of claim 6, wherein said metastable beta alloy is formed by explosive pressure welding.

9. The method of claim 6, wherein said metastable beta alloy is fonned by deposit welding.

10. The method of claim 5, wherein said metastable beta alloy is coated by diffusion welding.

11. The method of claim 5, wherein said metastable beta alloy is forming by explosive pressure welding.

12. The method of claim 5, wherein said metastable beta alloy is forming by deposit welding.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4167427 *Oct 18, 1977Sep 11, 1979Mitsubishi Jukogyo Kabushiki KaishaHeat treatment of titanium alloys
US4263375 *Dec 26, 1978Apr 21, 1981The Boeing CompanySuperplastically formed titanium structure
US4751044 *Aug 15, 1985Jun 14, 1988Westinghouse Electric Corp.Composite nuclear fuel cladding tubing and other core internal structures with improved corrosion resistance
US4871274 *Dec 24, 1987Oct 3, 1989Brother Kogyo Kabushiki KaishaTypewriter
US5247550 *Mar 27, 1992Sep 21, 1993Siemens Power CorporationCorrosion resistant zirconium liner for nuclear fuel rod cladding
US6306196 *Aug 4, 2000Oct 23, 2001Hitachi Metals, Ltd.Sintered Ti-system material product derived from injection molding of powder material and producing method thereof
US7396595 *Aug 30, 2002Jul 8, 2008Citizen Holdings Co., Ltd.Soft metal and method for preparation thereof, and exterior part of watch and method for preparation thereof
US7883662Nov 15, 2007Feb 8, 2011Viper TechnologiesMetal injection molding methods and feedstocks
US8124187Sep 8, 2009Feb 28, 2012Viper TechnologiesMethods of forming porous coatings on substrates
US20040231159 *Aug 30, 2002Nov 25, 2004Yoshitsugu ShibuyaSoft metal and method for preparation thereof, and exterior part of watch and method for preparation thereof
US20090129961 *Nov 15, 2007May 21, 2009Viper Technologies Llc, D.B.A. Thortex, Inc.Metal injection molding methods and feedstocks
Classifications
U.S. Classification428/636, 148/537, 428/938, 428/940, 148/407, 428/660, 148/672, 428/669, 148/669
International ClassificationC22C14/00, C22C16/00, C22F1/18, B23K35/32
Cooperative ClassificationY10S428/938, B23K35/325, C22C16/00, Y10S428/94, C22C14/00, C22F1/186
European ClassificationC22F1/18D, C22C14/00, C22C16/00, B23K35/32C