Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
1999-07-01
2001-02-27
Zimmerman, John J. (Department: 1775)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C428S679000, C428S685000, C428S941000, C148S530000
Reexamination Certificate
active
06194088
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an intermetallic-compound coated stainless steel, which can be used for parts requiring excellent rigidity, toughness, wear resistance and corrosion resistance, for example, structural parts such as gears and bearings, and cutting tools such as hair clippers and blades for electric shavers, and a method of producing the same.
2. Disclosure of the Prior Art
In the past, carbon tool steels, high carbon stainless steels, or precipitation-hardening stainless steels have been used to structural parts such as gears and bearings, and cutting tools such as hair clippers and blades for electric shavers. Although these materials are excellent in toughness, the wear resistance is not enough. To improve the wear resistance, conventional ceramics can be used. However, they have not been practical yet in applications requiring complex configuration or sharp edge because of poor toughness and workability of the ceramics. On the other hand, a surface modification of the foregoing steels can be performed by coating a hard material having excellent corrosion resistance such as alumina by means of physical vapor deposition (PVD) method or chemical vapor deposition (CVD). In this case, since a thickness of the coated hard material is very thin, for example, 0.1 &mgr;m, sufficient wear resistance has not been obtained yet. In addition, there is a problem that the adhesion between the coated hard material and the steels is not enough.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an intermetallic-compound coated stainless steel having excellent rigidity, toughness, wear resistance and corrosion resistance. That is, the coated stainless steel comprises a substrate of a martensite stainless steel, and a hard film having a bottom surface adhered to the substrate and an exposed top surface. The stainless steel of the substrate has a Vickers hardness of 400 or more. The hard film has an outermost layer made of a compound selected from the group consisting of a Ti—Ni intermetallic compound, Ti—Fe intermetallic compound, and a mixture of the Ti—Ni intermetallic compound and a Ti—Cu intermetallic compound.
When the outermost layer is made of the Ti—Fe intermetallic compound, it is preferred that the hard film has a TiFe
2
layer, and a TiFe layer formed on the TiFe
2
layer as the outermost layer.
When the outermost layer is made of the Ti—Ni intermetallic compound, it is preferred that the hard film has a TiNi
3
layer, and a TiNi layer formed on the TiNi
3
layer as the outermost layer.
When the outermost layer is made of the mixture of the Ti—Ni intermetallic compound and the Ti—Cu intermetallic compound, it is preferred that the hard film has a mixture layer of TiNi and TiCu as the outermost layer.
A further object of the present invention is to provide a method of producing the intermetallic-compound coated stainless steel. That is, a laminate is prepared by cladding an outer sheet of Ti or a Ti alloy directly on a surface of the martensite stainless steel, or cladding the outer sheet on the martensite stainless steel through an intermediate sheet of Ni, Fe or a Ni—Cu alloy. Then, a quench hardening treatment is performed to the laminate. That is, the laminate is heated and kept at a temperature of 900° C. to 1150° C. for 30 seconds to 5 minutes, and then cooled at a cooling rate of 1° C./sec or more. By the quench hardening treatment, the stainless steel is hardened to a Vickers hardness of 400 or more, and at the same time the hard film is formed on the hardened stainless steel. When the laminate is prepared by cladding the outer sheet on the stainless steel sheet through the intermediate sheet, the hard film having the outermost layer made of an intermetallic compound between Ti of the outer sheet and the metal element of the intermediate sheet is formed on the stainless steel by the foregoing hardening treatment. On the other hand, when the laminate is prepared by cladding the outer sheet directly on the stainless steel sheet, the hard film having a TiC layer, a TiFe
2
layer formed on the TiC layer, and a TiFe layer formed on the TiFe
2
layer as the outermost layer, is formed on the stainless steel by the foregoing hardening treatment.
When using the intermediate sheet, it is preferred that a thickness of the outer sheet in the laminate is within a range of 1 to 10 &mgr;m and a thickness of the intermediate sheet in the laminate is 1 to 3 times of the thickness of the outer sheet.
In the above method, when the laminate is worked by a plastic deformation prior to the foregoing hardening treatment, it is preferred to perform the working after an annealing treatment in which the laminate is heated and kept at a temperature of 700° C. to 800° C. for 15 seconds to 2 minutes.
These and still other objects and advantages will become apparent from the following detail description of the preferred embodiments and examples of the invention referring to the attached drawings.
REFERENCES:
patent: 2786265 (1957-03-01), Keay, Jr.
patent: 3015885 (1962-01-01), McEuen et al.
patent: 3071491 (1963-01-01), Horn et al.
patent: 3125805 (1964-03-01), Horigan, Jr.
patent: 3615902 (1971-10-01), Lesney
patent: 4485149 (1984-11-01), Sprenger et al.
patent: 4612259 (1986-09-01), Ueda
patent: 4839242 (1989-06-01), Murayama et al.
patent: 5190831 (1993-03-01), Banker
patent: 62-203687 (1987-09-01), None
patent: 63-318985 (1988-12-01), None
patent: 1-35918 (1989-07-01), None
patent: 1-309791 (1989-12-01), None
patent: 3-115559 (1991-05-01), None
patent: 10-29104 (1998-02-01), None
Fujimoto Shinji
Hamada Tadashi
Imai Junji
Iwane Fumio
Sakon Shigetoshi
Arent Fox Kintner & Plotkin & Kahn, PLLC
Daido Steel Co. Ltd.
Zimmerman John J.
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