JPS6211066B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention focuses on Co--Fe--Si--B, which is an amorphous metal.
Regarding plastic working methods for alloys, the gist is that in plastic working of metal-metalloid amorphous alloys at high temperatures, the vertical axis of a piece number table with logarithmic scale on the vertical axis is the surface material heating time (unit: seconds), and the horizontal axis is the processing temperature (unit: °C), and the straight line extending horizontally from the position where the material heating time is 14 seconds is the processing temperature of 400 seconds.
Let P ₁ be the intersection with the line extending upward from the ℃ position,
The intersection of the line extending horizontally from the position where the material heating time is 5 seconds and the line extending upward from the position where the processing temperature is 500℃ is P ₂ , and the processing temperature is 400℃ below the straight line connecting P ₁ and P ₂ .
The area surrounded by ~500 is defined as the plastic processing area, and a coining die with a textured surface is used to process Co.
- A method for plastic working an amorphous metal, which is characterized by plastic working a Fe-Si-B alloy. The material of the outer blade for conventional electric razors is
SUS420j2 (stainless steel alloy) was used.
However, the strength of this stainless steel alloy in the quenched state is 180 Kg/mm ² , Young's modulus 2.1×10 ⁴ Kg/mm ² ,
Hardness is 575HV. Currently, attempts are being made to increase the aperture ratio and reduce the thickness of the outer blades for electric shavers in order to achieve a closer shave, but there are limits to their strength. The above-mentioned materials had problems in terms of corrosion resistance when washed with water. The present invention has been made in view of the drawbacks of the conventional examples, and its purpose is to provide a method for plastic working of amorphous metals having excellent corrosion resistance and high strength. The present invention will be described in detail below with reference to illustrated embodiments.
Metal-metalloid amorphous alloy (amorphous Co-
In more detail, the Fe-Si-B alloy) is amorphous.
_It is _a Co _70.5 Fe _4.5 Si _{12.5 B 12.5} alloy _. The details of _the amorphous Co _{70.5 Fe 4.5 Si 12.5} B _12.5 alloy ( _metal -metalloid amorphous alloy) will be described below. _Figure 1 shows the _temperature dependence of _the tensile properties _{of the amorphous Co70.5Fe4.5Si12.5B12.5 alloy} . In the figure, the solid line indicates the breaking stress (maximum stress), the units of which are scaled on the left, and the broken line indicates plastic elongation, whose units are scaled on the right. The test was carried out at a tensile rate of 1 mm/min after holding at each temperature in the temperature range of 0 to 600°C for 15 minutes. here
It can be seen that clear yielding occurs at around 470 to 510°C, showing plastic elongation of about 30% or more. Also,
It can be seen that when the temperature exceeds the glass transition temperature (Tg≒510°C), many pieces break early due to embrittlement, and the strength decreases significantly. Generally, metal-metalloid amorphous alloys are
As the temperature rises, the following crystallization process occurs.

[Table] The above glass transition temperature (Tg) is estimated to be near the metastable phase (MS), and above the glass transition temperature (Tg), the material becomes completely brittle due to crystallization and breaks early. It becomes like this. Therefore, it is desirable that the upper limit of the temperature range when applying plastic working to amorphous metals is below the glass transition temperature (Tg) (approximately 500°C for this alloy);
It is necessary to satisfy the plastic elongation (approximately 20% or more) required for producing outer blades for electric shavers, and the lower limit of the temperature range is preferably approximately 400°C or higher for this alloy. Next, the embrittlement behavior of metal-metalloid amorphous alloys due to thermal instability will be explained. This embrittlement phenomenon of metal-metalloid amorphous alloys depends on the transition process from the amorphous phase to the crystalline phase, and is formed by phase separation due to structural relaxation that occurs in the pre-crystallization stage. Caused by various brittle precipitates. Note that after crystallization, embrittlement becomes extremely noticeable. Figure 2 shows _the temperature _dependence of embrittlement in the pre _- crystallization stage of the amorphous _{Co70.5Fe4.5Si12.5B12.5} alloy when _{the material} was heated for _{10 minutes} . Material heating time
An example of the time dependence of the same alloy at 500 (±5)°C is shown. 2 and 3, the embrittlement coefficient EP on the vertical axis is plotted on a logarithmic scale, and further, in FIG. 3, the material heating time on the horizontal axis is also plotted on a logarithmic scale. However, the embrittlement coefficient EP was defined by the following equation based on the bending test. However, EP: embrittlement coefficient t: Thickness of test piece (mm) Rmin: Minimum bending radius (mm) In general, amorphous metals undergo multiple sliding deformations.
Although 180° tight bending is possible, if it becomes brittle due to high-temperature treatment, its deformability decreases significantly and it begins to show brittle fracture. In addition, an amorphous metal that has been rapidly cooled can be bent closely by 180 degrees, so Rmin→0 and EP→1. On the other hand, as it becomes brittle, Rmin increases and EP reaches zero.
approach. Now, referring to Figures 2 and 3,
The embrittlement of metal-metalloid alloys is caused by heating temperature,
It can be seen that this becomes more noticeable as the heating time increases. Therefore, the optimum value of the machining time is determined by the machining temperature T.
(400≦T≦500°C) It can be seen that it is sufficient to take the temperature within the prescribed range from the lower limit (400°C). Also, the third
From the time dependence of embrittlement in the figure, it can be seen that at a heating temperature of 500°C, the properties change after a heating time of 5 seconds, and it is desirable to heat the material within 5 seconds. On the other hand, FIG. 4 shows the heating time dependence of the shear stress τ using a heating temperature T: 432 (±3)° C. as an example.
In the figure, the shear stress τ on the vertical axis and the material processing time on the horizontal axis are plotted on a logarithmic scale. In addition, the said shear stress (tau) was defined by the following formula by the tear test. τ=P/l・t (Kg/mm ² ) (2) where τ: Shear stress (Kg/mm ² ) P: Load (Kg) l: Single crack length (mm) t: Plate thickness (mm) Heating time T: At 432°C, the shear stress τ rapidly decreased after the heating time of 10 seconds and the material became brittle, indicating that it is desirable to heat the material within 10 seconds. Based on the above considerations, it is desirable that the optimum pressure application conditions for manufacturing a good razor outer cutter made of a metal-metalloid amorphous alloy be within the range of the hatchings shown in Figures 5A and 5B. In addition, in the figure (b), the material heating time on the vertical axis is scaled on a logarithmic scale. Next, we will discuss in detail the case where this alloy is used for the outer blade of an electric shaver. FIG. 6 shows an example of the structure of a coining die A for manufacturing an outer cutter for an electric shaver using the present invention. Cartridge heaters 5 are placed on both sides of the mold to heat the mold, and the main amorphous alloy, which is the material 1, is placed between the cavity 3 and the coining plate 2.
The structure is such that the cavity shape is transferred to the material 1 by inserting it between the two and pressing the punch 4. Note that after coining, the material 1 is ground and drilled to produce an outer cutter. (Soft Stamp Processing) Here, the coining plate 2 was made of a soft metal such as aluminum or copper, which can be used even in high temperature conditions, is easily deformed, and has relatively high elongation, and the cavity shape was transferred to the material 1. Here 8 is the back plate,
9 is a retainer, 10 is a cavity holder, 13 is a back plate, 14 is a heat insulator, 15 is a die set upper plate, and 16 is a die set lower plate. Although soft metals such as aluminum and copper are not so-called elastic bodies like rubber, they can be used repeatedly due to their deformability. In addition, when using this soft metal as the coining plate 2, please refer to Fig. 8a.
As shown in ~c, once coined, the stamp plate 2 to which the cavity shape has been transferred is subjected to aging treatment (quenching).
By hardening the coining plate 2 and using the coining plate 2 to perform coining as shown in Fig. 8 d to f, the stress concentration at the cavity shoulder is alleviated as shown in Fig. 7. This makes it possible to minimize cross-sectional shrinkage of the material 1 in that portion. As the soft metal to be subjected to the aging treatment, it is desirable to use, for example, beryllium copper, or soft copper for quench hardening. This amorphous alloy, which has just been coined and sent out at a high temperature (400 to 500°C), is in a heated state, so by forcibly quenching it with an inert gas, for example, the embrittlement of the amorphous metal can be significantly reduced. Preventing. In this respect, as mentioned in the time dependence of embrittlement of the present amorphous alloy in Figure 3, the embrittlement behavior due to thermal instability of the present amorphous alloy is caused by a long material heating time. Indeed, it tends to promote embrittlement. Therefore, by forcibly quenching the heated amorphous alloy that has just been delivered, using an inert gas, for example, it is possible to significantly shorten the material heating time, and as a result, it is effective in preventing embrittlement. bring about. In addition to this, there are various other cooling methods such as cooling medium (roll etc.) and air. FIG. 9 shows the structure of the coining material hoop 12 of the present invention.
Figures a and b show illustrations of the process. The coining material hoop 12 is made by alternately and integrally connecting one part of the present amorphous alloy material and a thin foil 11 of another type of material. Therefore, in order to shorten the heating time of the material 1 of the present amorphous alloy during coining, when not coining [Fig. 10a]
In this case, the thin foil 11 of the other material is placed in the coining mold A, and the material 1 of the present amorphous alloy is placed in the coining mold A.
This prevents the metal from being heated by the coining die A. next,
Simultaneously with the start of coining by pressing the punch 4, the coining material hoop 12 is quickly sent, and the coining material hoop 12 is arranged so that a part of the raw material of the present amorphous alloy is on the cavity 3, and coined. [FIG. 10b] Immediately after coining, the coining material hoop 12 is sent so that the other material thin foil 11 is placed in the coining die A. [Fig. 10a] By repeating the above-mentioned series of operations, the heating time of one part of the material of the present amorphous alloy can be significantly shortened, resulting in a good amorphous metal electric shaver without embrittlement. Outer blades can be manufactured. In order to further shorten the heating time for the material 1 of this amorphous alloy, the coining material hoop 12 is placed between the upper mold 6 (punch/retainer side) and the lower mold 7 (cavity/cavity holder side). By positioning
(See Figure 10a) When coining, the coining material hoop 12 is sent, and a portion of the material of the present amorphous alloy is
When placing it on the cavity 3, the material 1 of the present amorphous alloy is not in direct contact with the coining die A until the upper die 6 is pressed down and comes into contact with the lower die 7. By doing so, the heating time can be shortened, and an excellent amorphous metal outer blade for an electric shaver without embrittlement can be manufactured. Since the present invention has the above-mentioned configuration, Co-Fe-Si is produced using a coining mold with an uneven finish.
- B alloy can be plastic-processed within the optimum plastic-processing range, and there is an advantage that damage due to insufficient elongation and plastic fracture due to glass transition temperature can be prevented and a sound plastic-processed product can be obtained.

[Brief explanation of the drawing]

Figure 1 _{shows the amorphous Co70.5Fe4.5Si12 .
5} B ₁₂ . ₅ A graph showing the temperature dependence of the tensile properties of the alloy. Figure 2 is a semi-logarithmic graph showing the temperature dependence of the embrittlement of the same as above. Figure 3 is a graph showing the time dependence of the embrittlement of the same as above. Figure 4 is a double logarithmic graph showing the heating time dependence of shear stress, Figure 5 A is a material heating time vs. processing temperature graph showing the optimum coining conditions of the present invention, Figure 5 B is a graph showing the heating time dependence of shear stress. Semilogarithm graph in Figure 5 A,
Fig. 6 is a front view of the coining die used in the present invention, Fig. 7 is a longitudinal cross-sectional view when a cross-section reduction phenomenon occurs in the shoulder of the material during coining, and Fig. 8 a to f are the coining molds used in the present invention. FIGS. 9A and 9B are a plan view and a sectional view of the coining material hoop used in the present invention, and FIGS. 10A and 10B are schematic front views showing the coining procedure in the present invention. .

Claims (1)

[Claims] 1 Co, a metal-metalloid amorphous alloy
-In plastic working of Fe-Si-B alloy at high temperatures, the vertical axis of the semi-logarithmic table with logarithmic scale on the vertical axis is the material heating time (in seconds), and the horizontal axis is the processing temperature (in °C) Let P ₁ be the intersection of a straight line extending horizontally from the position where the material heating time is 14 seconds and a line extending upward from the position where the heating temperature is 400℃, and Stretched wire and processing temperature
The intersection with the line extending upward from the 500°C position is _P2 , and the processing temperature is 400°C to 500°C under the straight line connecting _P1 and _P2 .
The area surrounded by
- A method for plastic working of amorphous metals, which is characterized by plastic working of B alloy.