JPS6143717A - Production of glasses frame - Google Patents

Abstract

PURPOSE:To produce a glasses frame where soldering is made easy and the required soldering strength is secured, by subjecting a composite billet, which has a metal consisting essentially of Ti subjected to beta treatment as the billet core material and has a noble metal as a sheath material, to hot hydrostatic pressure extrusion and using materials obtained in this manner. CONSTITUTION:A composite billet 7 which is produced with the metal consisting essentially of Ti subjected to beta treatment and set to <=200mum crystal particle size as the billet core material and the noble metal as the billet sheath material and consists of a core part 8, a body part outside cylinder 9, etc. is subjected to hot hydrostatic pressure extrusion at 550-700 deg.C, and the obtained extruded material is subjected to the area reducing processing to obtain a composite wire rod. This composite wire rod is annealed for <=20min at 550-650 deg.C before it is worked plastically into a glasses frame shape and a temple shape, and thereafter, plastical working is performed, and individual parts are soldered at <=700 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to glasses frames! l! ! ! Regarding the method of sending
In particular, the present invention relates to a method of manufacturing eyeglass frames using a composite wire material in which the core material is made of gold mainly made of Ti and the outer sheath material is made of a noble metal.

(Prior Art) Ti is a material with excellent corrosion resistance, workability, plating properties, etc., and is also lightweight, so it has recently attracted attention as a material for metal eyeglass frames.

However, eyeglass frames are manufactured by brazing the eyeglass frames, temples, and other parts, and Ti is disadvantageous in that it has poor brazing properties.

Therefore, a composite wire material has been proposed in which Ti is used as a core material and a noble metal with excellent brazing properties is bonded by craft to the surface of the core material.

(Problem to be solved by the invention) However, in this composite wire, a very brittle metal interlayer compound is formed between the core material and the outer sheath material during heating for brazing, so brazing is difficult. The problem is that it is small.

From this point of view, the core material is made of gold mainly composed of Ti,
A Ti-based wire material for eyeglass frames is proposed in which the surface layer is made of a noble metal, and the intermediate layer interposed between the core material and the surface layer is made of a metal that does not form a brittle intermetallic compound with Ti at high temperatures, such as a Ni layer. has been done.

Although this proposed conventional Ti-based wire material for eyeglass frames has certain advantages, it is difficult to manufacture because it has a so-called three-layer structure, making it unsuitable for mass production. For the glasses frames, processing is essential, such as forming lens grooves, and for the temples, swaging and pressing are required to create a flat cross-sectional shape.There is no solution to the problem of thinning of the surface layer during plastic processing. Since this method had not yet been developed, it was currently not suitable for use in eyeglass frames.

In view of these circumstances, the present invention provides a so-called 27i structure eyeglass frame in which the core material is a metal mainly composed of T and the outer covering material is made of a highly decorative precious metal. There is no possibility of forming or producing intermetallic compounds between the outer covering material, and the outer covering material does not become selectively thinner when plastic working into the shape of the eyeglass frame, and brazing is also possible. The object of the present invention is to provide a new method for manufacturing eyeglass frames with excellent decorative properties, which allows easy and necessary brazing to ensure strength without forming intermetallic compounds.

(Means to solve the problem) The following measures will be taken to achieve the above objectives.

That is, as a material for eyeglass frames, a composite billet assembled with a billet core material made of a Ti-based metal that has been subjected to β treatment and whose crystal grain size is 200 μm or less and a noble metal used as a billet outer material is used as a material for eyeglass frames. A composite wire manufactured by hot isostatic extrusion at 700°C and surface reduction processing of the obtained extruded material was used, and the composite wire was heated at 550 °C prior to plastic working into the shape of an eyeglass frame and the shape of a temple.
The parts are annealed at ~650°C for 20 minutes or less, and then subjected to the above-mentioned plastic working, and then brazed at 700°C or less.

(Function) According to the above method, the composite wire material that is the material of the eyeglass frame is made of a billet core material made of a Ti-based metal that has been subjected to β treatment and has a crystal grain size of 200 μm or less.
, a composite billet assembled with precious metals as a billet jacket material is hot isostatically extruded, and the resulting extruded material is subjected to area reduction processing, so it can be used not only as an extruded material but also as a core material and a jacket material of a composite wire. The interface of
Since the process is carried out at a temperature of ~700°C, no intermetallic compounds that cause peeling of the jacket are generated at the interface between the core material and the jacket material. Then, before plastic working the composite wire into the shape of an eyeglass frame and the shape of a temple, it is heated at 550 to 650°C
Since the annealing is performed for less than 0 minutes, the formation of intermetallic compounds at the interface is suppressed, the deformation resistance between the core material and the outer sheath material is lowered, and the two are brought as close together as possible. Interfacial destruction due to slipping can be reliably prevented. Furthermore, when brazing various parts,
Since it is carried out at a temperature of 700° C. or lower, no intermetallic compounds are formed at the interface, and peeling, which conventionally occurs in brazing parts, can be prevented as much as possible.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

No. 1ryJ shows an example of glasses 1 having a glasses frame obtained by the present invention. The eyeglass frame is composed of a temple 5 and the like, and at least a portion indicated by the reference numeral 6 is soldered.

Referring to FIG. 2, a flowchart of the present invention is shown as an example. A composite wire material that is a material for eyeglass frames is made by hot isostatic extrusion and area reduction processing, and this composite wire material is used to form eyeglass frames. A spectacle frame including at least a temple is manufactured by brazing each component.

Therefore, the process of making a composite wire by hot isostatic extrusion, and the process of plastic working the composite wire into the shape of an eyeglass frame and brazing can also be performed as a series of processes. However, in the current industrial structure, the process of making composite wire is carried out by so-called material manufacturers, and the process of processing it into the shape of eyeglass frames is carried out by so-called eyeglass frame processing companies. It is often carried out by dividing the labor separately.

Therefore, for the sake of explanation, a method for making a composite wire will first be described in detail, and then a method for manufacturing an eyeglass frame using the composite wire will be described in detail.

In FIG. 2, A is an ingot serving as a core material, for example, KS50. It is made of pure titanium such as KS70, and the in-boll A is subjected to hot forging process B and then scale removed.
After machining process C such as dimension matching is carried out, β treatment is carried out, followed by a degreasing process to clean the bonding interface.

On the other hand, the precious metal bending plate that becomes the outer covering material is formed into a cylindrical body B to be used as the barbed outer cylinder of the extruded billet described later, and then subjected to a degreasing process C to clean the bonding interface. will be attached.

The noble metal used as the outer covering material is a material that forms intermetallic compounds with Ti, or brazing during frame forming produces a significantly large amount of intermetallic compounds even at the processing temperature (usually 500 to 750°C). Materials that do not produce compounds,
Furthermore, the softening temperature of the molding curvature (usually 500 to 750°C)
It is necessary to select materials that do not generate intermetallic compounds. In addition, since glasses are exposed to a salt atmosphere due to sweat and the like, they must be resistant to corrosion, and must have excellent corrosion resistance.

Platinum (Pt) is a precious metal that satisfies the above requirements.
, gold (Au), PL-Au-Ag, palladium (P
Alloys such as d), Pd-Ag, Au-Ag5 and Au-Ni are conceivable, but the ease of extrusion during hot isostatic extrusion, ease of molding and softening must also be taken into consideration.

In other words, alloys such as pt, I't-1r, and Pt-Ru have a melting point of 1,771 to 1,885°C, high resistance to hot deformation, and a high softening temperature, so they are not preferable (Pd, Pd, etc.).
-Ru also has a relatively high melting point of 1550 to 1580°C, and the same can be said. On the other hand, Ag is soft but has poor sulfidation resistance, so it is not preferred. In this sense, Pd-8g alloy and ^1l-A(I alloy are superior. That is,
The melting point and hardness of the I'd-tt5 alloy differ depending on the Pd content, but the 10-80% Pd alloy has high hardness and high wear resistance, and has improved sulfidation resistance compared to Ag, and has a high resistance to Pd. The effect of organic gas is less compared to that of A.
u-Ag alloy also has excellent sulfidation resistance and corrosion resistance, and has a melting point of 10
Since the temperature is around 00°C, molding and softening treatment are easy.

From the above points of view, the noble metals used as outer covering materials are:
Preferred are Au-Ag alloy, Ag-Pd alloy, and Pd-Cu alloy. Furthermore, in consideration of the suitability of the softening temperature, those marked with a circle in Table 1 are preferable.

(Next page) Table 1 (Continued from Table 1) Then, the core material and outer covering material that have undergone the degreasing steps E and C' are shown in Figure 3 after passing through the fitting step F and the electron beam welding step G. A composite billet 7 as shown is obtained. In addition, prior to the fitting process F, the core material and the outer sheath material are cleaned by a degreasing process EC'. It is possible to suppress the formation of intermetallic compounds at the interface between
A good extruded material is obtained.

As shown in FIG. 3, the composite billet 7 is fitted inside the body outer cylinder 9, which is made by bending a noble metal plate serving as the jacket material, and the body outside M9, and It consists of a core part 8 formed of material, an a-head conical part 12 and a bottom part 10 that are joined to both ends of the body outer cylinder 9, and the core part 8 is attached to both ends of the body outer cylinder 9. , frustoconical part 12 and bottom part 10 under vacuum
are obtained by integrating them via a seal portion 11 by electron beam welding. Incidentally, the truncated conical portion 12 and the bottom portion 10 may be made of an inexpensive copper material, and these are prepared separately by being processed into a predetermined shape, degreased and cleaned.

Here, prior to creating the composite billet 7, the core material (titanium) is made of an ingot of 700 to 900
It is hot worked at ℃ in the same manner as before, and then subjected to β treatment annealing to eliminate the anisotropy. At this time, the treatment temperature and holding time determine the grain size of the core material after β treatment. You need to select an appropriate value for the base.

The crystal grain size of the core material greatly affects the interfacial properties between the core material and the outer covering material in the extruded material obtained by hot isostatically extruding a composite billet, and the finer the crystal grains, the better the interfacial properties. . That is, in order to uniformly apply a thin noble metal layer to the surface of the titanium core material, the surface of the titanium core material needs to be as smooth as possible.

In order to reduce the crystal grain size, the holding time after heating the billet core material to the β treatment temperature may be made as short as possible. Even if the holding time is made as short as possible, there is no problem in terms of erasing anisotropy, since the anisotropy will be erased even if the holding time is extremely close to O. In addition, the crystal grains are
If the β treatment temperature is high, the grains will become coarse, but the grains can be made finer even if cold working is performed after the β treatment.

For example, FIG. 13 (2) shows a microstructure photograph (50x magnification) showing the crystal grains of a titanium material that has been subjected to 20% cold drawing after β treatment (950°C x 30 minutes), and A composite billet was prepared using a GA-Ni alloy as a billet core material and a billet outer covering material, and the composite billet was heated to 700°C.
A photograph (3.5x magnification) of the cross-sectional macrostructure of an extruded material obtained by hot isostatic extrusion in The unevenness at the interface with the material is extremely small, less than 50 μm.
It has a smooth surface. On the other hand, Fig. 13 (1) shows a microstructure photograph (the magnification is the same as (]) showing the crystal grains of a titanium material that has been subjected to only β treatment (950°C x 30 minutes) and a billet core material using the titanium material. (The outer cover material is shown in Figure 13 (11)
A photograph of the cross-sectional macrostructure of an extruded material (same as ) (magnification is +
11), but the titanium crystal grains are coarse and irregular, and the unevenness of the interface of the extruded material is 200 to 300.
It is quite large, on the order of μm.

In addition to the case shown in Figure 13 (2), hot isostatic extrusion was performed at 650 to 700°C with various pretreatment conditions for the titanium material serving as the billet core material, and the interface of the extruded material was investigated. It is shown in Table 2.

(Next page) From Table 2, it was found that good interface properties were obtained when the titanium crystal grain size was 200 μm or less. Furthermore, it can be seen that the crystal grains are finer when cold working is performed after the β treatment than when cold working is not performed.

In addition, the magnitude of cold working is preferably 6 to 20%. This is because if it is less than 6%, the grain refining effect will be small, while if it exceeds 20%, there is a fear of seizure during cold working.

The composite billet 7, an example of which is shown in FIG. 3, is subjected to a heating (550° C. to 700° C.) step indicated by the symbol 1 in FIG. , is extruded using a die coated with Mo32 paste by the hot isostatic extrusion method shown by reference numeral I in FIG. 2 to obtain an extruded material in which the noble metal and Ti bonding interface are in a diffusion bonded state.

Here, the reason why the temperature of the composite billet 7 is set in the range of 550°C to 700°C is as follows.

The higher the billet heating temperature, the lower the deformation resistance of the workpiece, which shortens the manufacturing process by processing high-reduction surfaces, but if the billet is heated to 750°C or higher and extruded, brittle intermetallic compounds will form at the composite interface. Therefore, the upper limit is set at 700°C. That is, as shown in the EPMA analysis results of the interface of the extruded product in Figure 8 (1) and (2), almost no intermetallic compounds are observed at the extrusion temperature of 700°C (Figure 8 Tl
)), whereas this is evident from the fact that at an extrusion temperature of 750°C, this was observed as shown in Figure 8 (2).

On the other hand, lowering the billet heating temperature is not preferable as a thin wire manufacturing condition because the extrusion ratio decreases and the number of drawing steps after extrusion increases, and the temperature is set at 550° C. or higher. 50
This is because the deformation resistance decreases markedly at temperatures above 0°C, and stability in actual operation is taken into consideration.For example, as shown in Figure 9, the hardness of various precious metals sharply decreases at temperatures above 500°C. is observed.

Although the extrusion ratio in hot isostatic extrusion differs depending on the extrusion temperature, the billet temperature (500°C or higher)
750℃ or lower), the lower limit can be lowered to 4 or lower, but as a rough guideline, 4 or higher. It can be used as a hit.

The extruded material thus extruded is subjected to a descaling process J by pickling and a drawing process K by cold drawing (not shown in FIG. 2), and then to the shape of the temple 5 shown in FIG. In the drawing process K, the drawing rate per elongation is set at 10 to 2.
0%, and the approach angle of the drawing die is taken into consideration so that the elongation rates of the core material and the outer covering material are constant, wire drawing is performed without annealing, and intermediate annealing is omitted.

That is, normally, the die angle for wire rods is smaller than that for tubes, and a range of 5 to 16 degrees is often used, and in this invention Since the object is a wire rod, it can be applied in the same way as a normal cotton swab.

However, since eyeglass frames are required to have a glossy surface, the area reduction rate is set at 20% or less to prevent wire breakage during drawing due to the 1g frictional force required for drawing, and in consideration of productivity. The lower limit of the area reduction rate is set at 10%.

Eyeglass frames are manufactured using the composite wire material manufactured in the above manner through plastic processing, brazing, plating and other coatings P, and final inspection Q.The eyeglass frames are formed into a cross-sectional shape. In order to do this, the swaging process h shown in Figure 2 is required for the crane 5.
° produces the plastically worked temple 5A shown in Fig. 6, and furthermore, the press working N'' produces the plastically worked temple 5 shown in Fig. 7. On the other hand, the eyeglass frame 3 is drawn. Alternatively, the preliminary processing M by roll rolling is plastically processed from the composite round bar material shown in Fig. 4 to the composite flat moon 3B, and further plastically processed by grooving N by drawing or roll rolling to form the lens groove 2A. (Figure 5 shows before and after processing).

Both the eyeglass frame 3 and the temple 5 of the eyeglass frame require plastic working as described above, and since this is a strong work, heat treatment is required before the work.

On the other hand, the composite wire rod has a two-layer structure as described above (1), and brazing by high frequency, resistance welding, etc. shown in Fig. 2 as a post-process takes process 0 into account and generates intermetallic compounds at the bonding interface between Ti and precious metals. It is important to try to suppress this, and
It is important to prevent the outer sheath material from becoming thinner due to plastic working, and for this reason, the deformation resistance of the core material and the outer sheath material should be made as close as possible to eliminate interfacial failure due to slippage at the bonding interface. Prior to plastic working, the numbers in Figure 2 are shown.

It is subjected to an annealing process at <550°C to 650°C for 20 minutes or less as indicated by Lo.

Although the annealing steps are shown separately in FIG. 2 for convenience of explanation, it is obvious that the extruded composite wire may be annealed without performing each step separately.

The reason why the annealing temperature and time at L' in the annealing process were specified will be explained with reference to FIGS. 10, 11, and 12+11 to (4).

That is, if the heat treatment temperature is high, intermetallic compounds will be generated, and in this example, the outer cover material is an Ag-Pd alloy and the core material is KS50, and both soften at 500 ° C. or higher. 1. The upper limit of the heat treatment temperature is set at 650° C. in consideration of the stability of the mulberry industry.

In other words, although the upper limit may actually be 700°C, the temperature is set at 650°C as shown in Figure 12 (11 (21).
When annealing was carried out at 700°C for 20 minutes, no intermetallic compounds were observed at the boundary, as shown in figure (1); however, when annealing was carried out at 700°C for 20 minutes, no formation of intermetallic compounds was observed in the same figure (1).
3+, Since the formation of intermetallic compounds is observed as shown in (4), the annealing time is set to 20 minutes or less,
Taking actual operation performance into consideration, 2 to 10 minutes is optimal. In consideration of safety, the upper limit temperature is set at 650°C.

On the other hand, the softening properties of KS-50, which is the core material of the composite material, are the first.
As shown in Fig. 1, the hardness decreases significantly above 520°C, so the lower limit of the annealing temperature is set at 550°C with a margin.
It is said to be ℃.

In addition, the glasses frame material is 1.5 to 4. A round wire of Qmmφ is press-formed into a flat plate, or plastic processing such as groove processing is performed, and at this time the core material is Ti.
For composite wire rods whose main material is metal and the outer sheath material is a noble metal, the outer sheath material is softer than the core material, and the outer sheath material tends to become thinner locally, so it is important to heat treat it (intermediate annealing). There is. By specifying the temperature range, the hardness ratio between the outer covering material and the core [O] should be as close to 1.0 as possible.
That is, by making ri and the deformation resistance of the noble metal as close as possible, it is possible to eliminate interface failure due to slippage at the bonding interface (see FIG. 10). From this point of view, the annealing temperature is set at 550°C to 650°C, and the annealing time is set at 20 minutes or less.

Note that the timing of such heat treatment is preferably during the process of drawing a round wire with a continuous drawing rate of 90% or more. On the other hand, the composite wire rod in this case used as a material for eyeglass frames can be continuously drawn and has a track record of continuous drawing processing rate of 98%, and the hardness (Hv) of the continuous drawn material varies depending on the component ratio in Ag-Pd alloys. But 150-200.

For KS-50, it is 260-280.

The frame material annealed prior to plastic working is subjected to downward pressing M and grooving N to form an eyeglass frame 3 as a part of the eyeglass frame, as shown in FIG.
Swaging M'% Bracing N' is performed to form temples 5 as parts of the eyeglass frame, and parts including these are brazed at various locations shown in FIG. 1 by high frequency or resistance welding.

This brazing process uses BAg-4 as the brazing material at a temperature of 6.
Experiments were conducted at 00°C, 650°C, 700°C, 750°C, and 800°C for a heating time of 2 minutes.

The result of observing the cross section of the sample and investigating the formation of intermetallic compounds at the interface between the core material KS-50 and the silver-palladium alloy was 700.
At temperatures below 7°C, almost no intermetallic compounds are formed.
At 50°C and 800°C, the above-mentioned compound was observed at the interface.

It should be noted that the time involved in brazing is a practical matter, and the manufacturing of eyeglass frames is a so-called assembly line work, so it does not pose a problem as it can be completed instantly, and the lower temperature limit for brazing depends on the selection of the brazing material and workability. It will be different.

(Effects of the Invention) In summary, the present invention provides the following advantages as a method for manufacturing eyeglass frames.

During bending tests that add strain after brazing eyeglass frames, the brazed parts may peel off11, and peeling of the brazed parts is an important issue as this is a problem that occurs after going through many crafting processes. It becomes.

There are two types of this problem: brazing, which has a potential cause of peeling, and brazing, which sometimes causes peeling.

In the former case, after intermetallic compounds are formed at the interface due to the extrusion temperature and intermediate annealing conditions, cracks occur when cold working is applied because the intermetallic compounds are hard and brittle. The crack will develop and become exposed.

The latter is because intermetallic compounds are generated when the temperature is high during brazing, and cracks occur in the brittle intermetallic compound phase during strain application tests, leading to peeling. The brazing material is joined at the surface of the outer sheathing material, and does not affect the internal interface diffusion, so the temperature at which the brazing material is applied is the same as that at the brazing temperature.

In view of this point of view, in the present invention, the composite wire rod as a material for eyeglass frames is a core material manufactured by reducing the area of an extruded material obtained by hot isostatic extrusion at 550'C to 700C. Since it is a composite wire material whose main material is Ti and the outer sheath material is a noble metal, brazing may cause parts to peel off.
That is, it is advantageous in that potential causes are excluded from the material itself.

In addition, it is a potential cause during plastic processing of eyeglass frames using the above-mentioned materials.

When intermetallic compounds are formed, their significance disappears,
Moreover, prior to plastic working, it should be noted that brazing does not only ensure strength but also reduces the decorative function of the eyeglass frame due to local thinning of the outer covering material due to plastic working. This problem can be solved by annealing at 650°C for 20 minutes or less, and the problem of peeling during brazing can be solved by annealing at a temperature of 700°C or less. Furthermore, since the outer covering material is an expensive precious metal, the outer covering thickness of the composite wire is often required to be 10 to 50 μm, and therefore the interface between the core material and the outer covering material must be smooth. However, this requirement does not apply to composite billet
This is achieved by subjecting the i-core to β treatment and reducing the crystal grain size to 200 μm or less.

As described above, the method for manufacturing eyeglass frames of the present invention includes strict quality control and
High quality is ensured through temperature control, and it is excellent for producing highly decorative, high-quality eyeglass frames while keeping production costs down.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of glasses obtained by the present invention, Fig. 2 is a flowchart showing an example of the present invention, Fig. 3 is a cross-sectional view showing an example of a composite billet, and Fig. 4 is for glasses. 5 is a sectional view showing an example of the lower pressing knee of the frame, FIG. 5 is a sectional view showing an example of the same groove forming knee, FIG. 6 is a perspective view of an example of the swaging knee of the same crane, and FIG. 7 is a sectional view of the same pressing knee. Example perspective view,
Figure 8 is a diagram showing the EPMA analysis results of the extruded product interface.
Figure 9 is a graph showing the relationship between heating temperature and hardness for various noble metals and Ti, Figure 1θ and Figure 11 are graphs showing the relationship between hardness and annealing conditions, and Figure 12 (11 to (4) is Figure 13 shows the EPMA analysis results at the boundary during annealing of the composite wire. Yes. 1...glasses, 3...=glasses frame, 5...vine, 6
~... Brazing is part, l... isostatic pressure extrusion process, Lo
-...Annealing process, M, M', N, N'--Plastic working process, 0...-Brazing is a process.

Claims (1)

[Claims] 1. A composite billet assembled with a billet core made of a Ti-based metal that has been subjected to β treatment and whose crystal grain size is 200 μm or less and a noble metal used as a billet outer covering material.
Hot isostatic extrusion is performed at 50 to 700°C, the area of the obtained extruded material is reduced to obtain a composite wire, and the composite wire is used to prepare eyeglass frames and temples, and each part is brazed. Targeting a method for manufacturing eyeglass frames, the composite wire is annealed at 550 to 650°C for 20 minutes or less before plastic working into the eyeglass frame shape and temple shape, respectively. A method for manufacturing eyeglass frames, characterized by brazing parts at 700°C or less.