Title of Invention

"A METHOD FOR TREATING COPPER BASED ALLOY"

Abstract Method using a Cu-based alloy comprising one or several heat-deformation steps in the bi-phased alpha-beta structure, and one or several hot treatment steps to obtain a mono-phased alpha structure. The alloy contains copper, zinc, nickel and manganese and is resistant to corrosion, hotably to inks and gel-inks. The alloy is especially suited to the production of tips and reservoirs for writing implements.
Full Text The present invention a copper-based alloy and its applications and more precisely a copper-nickel-zinc alloy intended for use in the manufacture of ballpoint pen components.
It is known to use copper-based alloys of different composition to form tubular ink guides, ink reservoirs and tips of writing implements. Certain known alloys however have the inconvenience of being incompatible with the low-viscosity inks used in new generation ballpoint pens.
The incompatibility between the alloy and the ink can then reduce the implement's functional efficiency and comfort of writing. The ink leaks that may result cause the quality of the writing to deteriorate and, in the worst cases, stains and smears.
The resistance to gel-inks can be improved by increasing the alloy's copper content, as for example in alpha brass and in alpha copper-nickel-zinc alloys. This solution has however the inconvenience of reducing the alloy's heat-deformability. The poor heat-deformability of the prior art alloys implies higher production costs.
Another limitation of brass is that its yellow coloration is not appreciated by all consumers.
It is thus an aim of the present invention to propose an alloy and ballpoint pen components free from the limitations of the prior art.
According to the invention, these aims are achieved by the alloys, the devices and the methods that are the object of the claims of the corresponding categories, and for example by an alloy including:
between 44.1 and 45.6 parts by weight of Cu; between 35.6 and 37.1 parts by weight of Zn;

between 11.8 and 12.7 parts by weight of Ni; between 4.6 and 5.4 parts by weight of Mn.
The present invention will be better understood by reading the attached claims and the description given by way of example and illustrated by the attached figures, in which:
Fig. 1 represents a metallographic sectaiof an alloy according to the invention in a mono-phased alpha structure.
Fig. 1a represents a micrograph corresponding to figure 1.
Fig. 2 represents a metallographic section of a prior art copper-nickel-zinc alloy in a bi-phased alpha-beta structure.
Fig. 2a represents a micrograph corresponding to figure 2.
Fig. 3 represents a metallographic section of a prior art bi-phased copper-nickel-zinc alloy corroded following exposition to ink.
Fig. 3a represents a micrograph corresponding to figure 3.
Fig. 4 represents a diagram of a beta phase ratio of an alloy according to the invention according to the hot treatment temperature.
According to one aspect of the invention, the inventive alloy is a copper-nickel-zinc alloy of white, gray or silver color, having the following composition:

Table 1
(Table Removed)
This alloy has the characteristic of having two types of microstructures that can be controlled by hot treatment. The first, i.e. the mono-phased alpha structure, is essentially composed of a single crystalline phase of uniform structure. Figure 1 represents a microphotography of a metallographic section of the alloy according to the invention, showing the alpha structure. It will be observed that the alloy is composed essentially of a uniform solid solution of its components 10, apart from the black lead particles 82.
The inventive alloy can also have the bi-phased alpha-beta structure. This structure, represented in figure 2, has grains of a second phase 20, i.e. the beta phase, having a lower copper content than that of the alpha phase and which can be distinguished in figure 2 by their darker color.
The different structures of the inventive alloy are adapted to specific forming and machining processes. In particular, the bi-phased alpha-beta structure is favorable to heat-deformation, whilst the mono-phased alpha structure is favorable to cold-deformation.
The adjunction of lead in the alloy makes the machining operations easier, for example slicing. It would however also be possible to omit the lead, or to reduce its content, if this property is not required.
The inventive alloy can thus appear in both the mono-phased alpha structure and the bi-phased alpha-beta structure. It is however possible to control the structure by a hot treatment between 570°C and

780°C during 1-3 hours, followed by a fast cooling to ambient temperature. Following this treatment, the alloy's structure is essentially alpha.
The invention also includes alloys to which, besides the elements having the nature and proportions as defined by the table 1 here above, are added low quantities of other elements, metallic or not, such as magnesium (Mg), aluminum (Al), iron (Fe), phosphorus (P) or any other chemical element or species.
In a second example of alloy according to the invention, the alloy's composition is determined, except for unavoidable impurities, by the table 2 here after:
Table 2
(Table Removed)

Figure 4 represents the beta phase ratio according to the hot treatment temperature. The choice of the temperature of the hot treatment allows the ratio of the beta phase to be modified and, consequently, to obtain materials having different properties. In particular, hot treatment in the TT temperature range at temperatures included between 630°C and 7?0°C gives rise to a mono-phased alpha structure. The temperature range E is favorable to extrusion.
The diagram of figure 4 is specific to the alloy composition specified in table 2. According to another aspect of the invention, it would also be possible to adopt different proportions of Cu, Zn, Ni, Mn and Pb and obtain an alloy whose ratios of alpha and beta phases can be modified by hot treatment. In particular, the proportion of each of the alloy's components can be varied independently within the value range indicated

in table 1 or beyond. The temperatures required for modifying the structure of the obtained alloy will then be different.
The inventive alloy has increased resistance to corrosion due to gel-inks when it is in the mono-phased alpha structure. The beta phase is in fact the only one that is dissolved by gel-inks. Figure 3 represents a metallographic section of an alpha-beta copper-nickel-zinc alloy corroded by the chemical reaction with the ink. It can be observed that only the beta phase is attacked and that its dissolution leaves cavities 25.
Although the alloy of the invention described here above is particularly suited to making tips of writing implements, and in particular of ballpoint pens, the present invention is not limited to this specific use but also includes any other use of the inventive alloy.
According to another aspect of the invention, the alloy having the composition here above is first cast in small rods or bars or in any other shape adapted to heat-deformation.
Contrary to alpha copper-nickel-zinc alloys, the inventive alloy offers excellent deformability at high temperature. All the usual heat-deformation processes are possible. Typically, the small rods are heat-extruded at a temperature included between 720°C and 870°C, a temperature at which its structure is bi-phased alpha-beta. The wires thus obtained are then hot treated between 630°C and 720°C, as explained here above, to obtain the mono-phased alpha structure.
As the mono-phased alpha structure is suited to cold deformation, the extruded material is then drawn to obtain bars or wires of suitable diameter to form the tubes of ink guides, ink reservoirs or tips for writing implements.
The material thus obtained can easily be shaped by cold-working and machining, for example by embossing, machining, crimping, lathe turning, milling or any other process.

The mechanical characteristics of the inventive alloy treated as described here above depend on its level of cold working according to the following table:
Table 3

(Table Removed)
The mechanical resistance and breaking elongation in the above table have been determined according to the standardized method EN10002-1.





We claim:-
1. A method using an alloy composed of:
between 43 and 48 parts by weight of Cu;
between 33 and 38 parts by weight of Zn;
between 10 and 15 parts by weight of Ni;
between 3.5 and 6.5 parts by weight of Mn;
between 0 and 4 parts by weight of Pb;
where the alloy can have a mono-phased alpha structure a and a bi-phased alpha-beta structure α/ß, characterized in that the method comprises:
one or several steps of heat-deformaiton of the alloy in the bi-phased alpha-beta structure α/ß,
one or several steps of hot treatment to obtain said mono-phased alpha structure a.
2. A method as claimed in claim 1, characterized in that the method
comprises:
a step of casting the melted alloy;
one or several steps of heat-deformation of the alloy in the bi-phased alpha-beta structure α/ß;
one or several steps of hot treatment to obtain said mono-phased alpha structure a,
one or several steps of cold-deformation of the alloy in the mono-phased alpha structure a.
3. A method as claimed in claim 1, characterized by the temperature of
said hot treatment being comprised between 570ºC and 780ºC.

4. A method as claimed in claim 1, characterized by the temperature of said hot treatment being comprised between 630ºC and 720ºC.
5. A method as claimed in claim 4, characterized by the temperature of said heat deformation being comprised between 720ºC and 870ºC.
6. The use, in the making of writing tips or ink reservoirs of writing implements or ball-point pens, of an alloy composed of;
between 43 and 48 parts by weight of Cu;
between 33 and 38 parts by weight of Zn;
between 10 and 15 parts by weight of Ni;
between 3.5 and 6.5 parts by weight of Mn;
between 0 and 4 parts by weight of Pb;
characterized in that the alloy has a mono-phased alpha structure a that can be obtained by a hot treatment.
7. The use as claimed in claim 6, characterized by the alloy being
composed of:
between 44.1 and 45.6 parts by weight of Cu;
between 35.6 and 37.1 parts by weight of Zn;
between 11.8 and 12.7 parts by weight of Ni;
between 4.6 and 5.4 parts by weight of Mn;
between 1.35 and 1.85 parts by weight of Pb.
8. The use as claimed in claim 6, characterized by the temperature of said hot treatment being comprised between 570ºC and 780ºC.
9. A writing implement, comprising an alloy composed of: between 43 and 48 parts by weight of Cu;
between 33 and 38 parts by weight of Zn; between 10 and 15 parts by weight of Ni; between 3.5 and 6.5 parts by weight of Mn; between 0 and 4 parts by weight of Pb; a that can be obtained by a hot treatment.

10. A writing implement as claimed in the preceding claims, characterized by
the alloy being comprised in an ink reservoir and/or a writing tip.
11. A biphasic, non-homogeneous system for resolving a compound of
Formula A substantially as herein described with reference to the
foregoing description and examples.

Documents:

4215-DELNP-2005-Abstract-(15-10-2007).pdf

4215-delnp-2005-abstract.pdf

4215-delnp-2005-assignments.pdf

4215-DELNP-2005-Claims-(15-10-2007).pdf

4215-delnp-2005-claims.pdf

4215-DELNP-2005-Correspondence-Others-(05-09-2008).pdf

4215-DELNP-2005-Correspondence-Others-(15-10-2007).pdf

4215-delnp-2005-correspondence-others.pdf

4215-DELNP-2005-Description (Complete)-(15-10-2007).pdf

4215-delnp-2005-description (complete).pdf

4215-DELNP-2005-Drawings-(15-10-2007).pdf

4215-delnp-2005-drawings.pdf

4215-delnp-2005-form-1.pdf

4215-delnp-2005-form-13-(05-09-2008).pdf

4215-delnp-2005-form-18.pdf

4215-DELNP-2005-Form-2-(15-10-2007).pdf

4215-delnp-2005-form-2.pdf

4215-DELNP-2005-Form-3-(15-10-2007).pdf

4215-delnp-2005-form-3.pdf

4215-delnp-2005-form-5.pdf

abstract.jpg


Patent Number 223587
Indian Patent Application Number 4215/DELNP/2005
PG Journal Number 40/2008
Publication Date 03-Oct-2008
Grant Date 16-Sep-2008
Date of Filing 19-Sep-2005
Name of Patentee SWISSMETAL-UMS USINES METALLURGIQUES SUISSES SA
Applicant Address CH-2732 RECONVILIER, SWITZERLAND.
Inventors:
# Inventor's Name Inventor's Address
1 VINCENT, EMMANUEL RUE DE TIVOLI 49A, CH-2610 ST.-IMIER, SWITZERLAND.
2 TRAN, HUNG-QUOC CH. DE BARTOLOME 13C, CH-2504 BIENNE, SWITZERLAND.
3 GILLIERON, STEPHANE CH.DE I'ORGERIE IC, CH-2710 TAVANNES, SWITZERLAND.
PCT International Classification Number C22C
PCT International Application Number PCT/CH2004/000051
PCT International Filing date 2004-01-30
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 496/03 2003-03-21 Switzerland