JP4406746B2 - Manufacturing method of zinc alloy for fuse - Google Patents

Description

  The present invention relates to a fuse material and a fuse, and more particularly to a zinc alloy for fuses excellent in various characteristics for automobiles, a fuse, and a method for manufacturing the same.

At present, from the viewpoint of fusing characteristics, there are the following three types of fuses.
1. This type is called “Fast-acting fusing type”, which responds quickly to overcurrent and has a short fusing time, which is mainly used for protecting semiconductors.
2. It is called “time lag fusing type”, and it aims to protect the circuit with momentary overcurrent because the fusing time for overcurrent is long without fusing in response to momentary overcurrent such as motor starting current. The fuse for automobiles also belongs to this type.
3. This type is called “normally blown type” and has the intermediate characteristics of the above two types and is used for general circuits.

Conventionally, glass fuses made of pure zinc were used as automotive fuses in the past, but recently, zinc alloy systems such as blade-type fuses using Zn-Cu-Ti alloys mainly composed of zinc. In addition, the adjustment of the fusing characteristics of the fuse, such as the use of a special blade type fuse in which the fusing part is replaced with a zinc alloy wire, is also performed from the shape side, Furthermore, the fusing characteristics are also adjusted by assembling another member to the fusing part.
In addition, fuses require various processes in the manufacturing process, and processability is also an important factor.

Pure zinc has an electrical conductivity of 28% IACS and a melting point of 419.5 ° C., and a fuse made of pure zinc is a fast-acting blow type, and Zn-0.3 to 0.6% Cu-0. The 1-0.3% Ti alloy has a conductivity of 27% IACS and a melting point of 420-422 ° C., and corresponds to a normal blown mold (hereinafter, “component%” represents “% by weight”). As a proposal from the viewpoint of the material in relation to the fusing characteristics of such a fuse, Japanese Patent Laid-Open No. 10-134698 discloses a material comprising 0.5 to 17.0% of Al and the balance of Zn and inevitable impurities. A fuse zinc alloy is disclosed in which the melting temperature is lowered to 300 to 400 ° C.
Japanese Patent Laid-Open No. 10-134698

Recently, however, an increase in the capacity of the battery has been studied due to an increase in the number of electrical components for automobiles, and an increase in the battery voltage has been studied.
In this case, due to the increase in the number of circuits and the increase in density, conventional Zn-Cu-Ti alloy-based fuses have a high temperature rise during energization due to their resistance, and this heat causes surrounding cases and fuse housings. In addition, there is a problem that when the fusing part is blown by heat, arc discharge is generated and a fusing defect is likely to occur. Further, in this Zn-Cu-Ti alloy, when the fused part of the fuse is processed and finished into a thin plate, there is a problem in workability because a defect in dimension or a problem of cracking is likely to occur.

  Moreover, in the zinc material according to the technique of the above-mentioned Japanese Patent Laid-Open No. 10-134698, the Al content range is widened to 0.5 to 17.0%, but the mechanical strength is substantially reduced when Al is about 8% or less. When Al is 8% or more, and the phase diagram of the Zn-Al alloy (see FIG. 1) shows that the temperature difference between the liquidus and the solidus becomes 25 ° C. or more, the liquid and solid solution When the fuse is used as a fuse, it is not suitable as a fuse for automobiles due to poor fusing characteristics. Furthermore, the Zn-Al binary alloy system has a problem in long-term stability in terms of corrosion resistance. is there.

  In view of the above problems, the present invention can adjust the fusing characteristics without performing special processing such as assembling a separate member to the fusing part, and the temperature rise during energization is low compared to conventional products, In addition to improved mechanical properties and other characteristics such as workability such as press and forging, zinc for fuses that can be used stably as a fuse for automobiles for a long time and can be supplied as a relatively inexpensive material The purpose is to provide alloy materials and fuses.

  As a result of intensive studies mainly from the material viewpoint in order to solve the above-mentioned problems, the present inventors have found that the fuse material composition has extremely excellent characteristics by further adding Mg in addition to a predetermined amount of Al. As a result, the inventors have found that a novel zinc alloy material for fuses that can achieve the above-described object can be obtained, and have provided the present invention.

  That is, the present invention first includes zinc having a composition containing Al: 3.0 to 8.0% and Mg: 0.0005 to 0.06% by weight, with the balance being Zn and inevitable impurities. A zinc alloy for fuses, characterized in that it is an alloy material, secondly, the zinc alloy material for fuses according to the first aspect, wherein the zinc alloy material is for automotive fuses, and thirdly, the zinc alloy The fuse zinc according to claim 1 or 2, wherein the material is a zinc alloy material in which a plate-like body having the above-described composition and having a thickness of 0.5 to 1.0 mm is finished by forging and punching to form a fuse fusing part. 4) The zinc alloy for fuses according to 1 or 2, wherein the zinc alloy material is a wire having a diameter of 0.1 to 5.0 mm, and fifth, any of the first to fourth A fuse comprising the zinc alloy material according to claim 1 And sixth, rolling a zinc alloy material containing Al: 3.0-8.0% and Mg: 0.0005-0.06% by weight, the balance being composed of Zn and inevitable impurities Is a rolled plate having a thickness of 0.5 to 1.0 mm, and a forging process and punching are further performed on the rolled plate to form a fuse blown portion.

The fuse of the alloy of the present invention has a lower temperature rise when energized than the conventional alloy fuse, and can prevent adverse effects on the surrounding case and fuse housing. In addition, the fuse material of the alloy of the present invention is made of a zinc alloy for fuses with improved mechanical properties, press workability, forging workability, fusing properties, corrosion resistance and other properties, and can be used stably as a fuse for automobiles for a long period of time. Not only can it be made, but it can also be supplied as a low-priced material, so it has high economic value.
In addition, according to the present invention, by adjusting the temperature difference between the liquid phase and the solid phase line in the fuse material, a “normal fusing type”, “time lag fusing type”, Has the effect of obtaining a fuse capable of responding to each of the characteristics of the “fast moving fusing type”.

The present invention uses a Zn—Al—Mg-based zinc alloy material containing 3.0 to 8.0% Al and 0.0005 to 0.06% Mg as the fuse material, the balance being zinc and inevitable impurities. . This material has a lower melting point than (1) conventional Zn-0.3 to 0.6% Cu-0.1 to 0.3% Ti-based zinc alloy fuse materials, and (2) Al content ratio 1, the temperature difference between the liquid phase and the solidus, that is, the temperature range of the mixed region of the alloy liquid phase and the solid solution changes, as shown in the partial state diagram of FIG. By changing the blending ratio, the fusing time in the fuse can be enlarged or reduced.
FIG. 1 shows the difference between the liquidus, solidus and eutectoid transformation temperatures when the Al content is changed from 1.8 to 15.0% for a Zn-Al alloy containing 0.005% Mg. It is created based on the result of actual measurement by the present inventors using a thermal analysis technique.

  In manufacturing the fuse material using the zinc alloy of the present invention, any conventional manufacturing method such as a hot extrusion method, a vertical or horizontal continuous casting method, or a rotary strip casting method can be used. From the molten Zn-Al-Mg alloy having the composition of the present invention, for example, a rotary strip casting method (using a continuous casting machine having a casting wheel having a strip forming groove and a steel strip covering the same) and two stages A coil having a thickness of 3.5 to 8 mm can be manufactured by a combination of roll rolling methods.

This coil can be made into a coil having a thickness of 0.5 to 1.0 mm by performing cold rolling continuously through or without hot rolling at 150 to 300 ° C. Thereafter, slitting is performed so as to obtain an appropriate width, and 0.5 to 1.0 μm of copper base plating and 1-2 μm of Sn plating are performed. In this case, the order of slitting and plating may be reversed.
Next, by punching into a die of a fuse by press working, and by further repeating several times of forging and die cutting by pressing, a melted portion having a cross-sectional area required for a rating of 2 to 30 A with a thickness of 0.1 mm It is possible to produce a fuse having
This forging process is easy to finely adjust the degree of processing, and it is an extremely important process for controlling the fine thickness and uniformly controlling the crystal structure to maintain the mechanical characteristics and the fusing characteristics uniformly.

  The zinc alloy of the present invention can also be used as a thin wire fuse having a diameter of 0.1 to 5.0 mm. The zinc alloy of the present invention can be applied with a general wire drawing method without any problem in thin wire processing. That is, a cylindrical zinc alloy ingot is obtained by hot extrusion or by a combination of a rotary strip casting method and a multi-stage tandem rolling mill, and further finished into the small-diameter fuse wire by high-speed wire drawing. Can do.

A typical Zn-6.4% Al-0.005% Mg alloy fuse material in the present invention has a conductivity of 32% IACS and a melting point of 393 ° C.
That is, the fuse of the alloy composition of the present invention is excellent in electrical conductivity, has little resistance heat, and when the above temperature range is expanded, the fuse fusing temperature can be widened so that it can be blown by energization for a long time at a relatively low temperature. Become. Accordingly, this fuse material is suitable for producing a “time lag fusing type” fusing characteristic in which fusing is prevented by an overcurrent for a relatively long time, although fusing due to an instantaneous overcurrent is prevented.
This fuse material can also exhibit the “normally blown” characteristics similar to those of conventional general-purpose fuses by narrowing the temperature range. It is also possible to select a “fast moving fusing type” for a semiconductor circuit by selecting a eutectic component.

As a result, the fuse material of the present invention has higher conductivity and lower material resistance than those of the pure zinc or the conventional Zn-Cu-Ti-based zinc alloy, so that the rated current can be obtained by processing the fuse. The temperature rise of the terminal when energized is reduced, and there is a feature that the surrounding case and the fuse housing are not adversely affected.
In addition, since the melting point is low, the design value of the resistance can be lowered when designing a fuse of the same rating, and further, the temperature rise can be suppressed, so that it is extremely suitable as a fuse material.

In the case of addition of 8% or less Al alone in a zinc alloy for fuses, the mechanical strength is low, and as such, it is unsuitable as a fuse for automobiles. However, in the present invention, the mechanical strength improved by the addition of Mg is sufficient. Can make up for. On the other hand, if Al exceeds 8%, the mechanical strength is improved, but the distance between the liquidus line and the solidus line becomes too large, and the fusing property as a fuse becomes insufficient.
On the other hand, when the Al content is less than 3%, the electrical conductivity decreases, and therefore the temperature rise with respect to the energization of the fuse increases.
For this reason, in the present invention, the Al content is set to 3.0 to 8.0%.

By adding a small amount of Mg as a third element to a zinc alloy containing 3.0-8.0% Al, the mechanical strength is remarkably improved as described above without changing the melting point and conductivity. Can do. However, when Mg is less than 0.0005%, such an effect of improving the mechanical strength is not sufficient.
Further, when Mg is contained in an amount exceeding 0.06%, the elongation becomes small, which causes a problem in workability such as occurrence of cracks in rolling during production.
Further, the addition of Mg has a remarkable effect of improving the corrosion resistance of the zinc alloy fuse.
From the above results, in the present invention, the Mg content is set to 0.0005 to 0.06%.

The fuse material made of the zinc alloy of the present invention has a tensile strength of 200 N / mm ² or more, a hardness (Hv) of 50 or more, an elongation of 50% or more, a conductivity of 30% IACS or more, and a melting point of 380 to 418 ° C. is there.
For example, a Zn-6.4% Al-0.005% Mg alloy has a tensile strength of about 258 N / mm ² , a hardness of Hv = 70, and an elongation of about 50%.

On the other hand, Zn-6.4% Al alloy material not containing Mg has a tensile strength of about 160 N / mm ² and a hardness as low as Hv = 35, and is currently most frequently used as a fuse material for automobiles. The conductivity of the Zn-0.56% Cu-0.13% Ti alloy material is as low as 27% IACS.
That is, the superiority of the fuse material of the present invention alloy over the conventional material is clear, and when using the conventional production line, handling at the time of processing such as pressing and assembly is easy.

  It should be noted that the fuse material of the present invention alloy can adjust the fusing time by selecting the width between the liquidus line and the solidus line, and is not limited to “time lag fusing type” fuses such as automobile fuses, but for general circuits Can be used as a “fast-acting fusing type” fuse material for semiconductor circuits by applying strict conditions for components. In addition, it is a fuse material that does not contain lead compared to the most general solder fuses, and is a fuse that is friendly to the global environment.

  Inventive Examples Alloys 1 to 3 of each composition shown in Table 1 and Comparative Examples Alloys 1 to 6 including a conventional alloy made of Zn-Cu-Ti were cast, respectively, and the ingot was subjected to hot rolling and cold rolling. And processed into a rolled plate having a thickness of 0.8 mm. Next, the rolled plate is forged and thinned to a thickness of 0.1 mm as a fuse blown portion, and then finished by press punching to produce fuse terminals with rated currents of 5A and 25A to be used as a fuse material. A test material was used. However, since the comparative example alloy 4 was cracked during rolling, the subsequent processing was stopped and no measurement test was performed.

About the test material except the comparative example alloy 4, the measurement test was done about mechanical characteristics, electrical conductivity, workability, and also the fusing characteristics and temperature rise.
The results are shown in Tables 2 and 3.
In the above measurement test, the mechanical properties are evaluated by measuring the tensile strength, elongation, and hardness, and in particular, good (◯), poor (based on a tensile strength of 200 N / mm ² or more and a hardness of Hv 50 or more. ×). As for workability, press workability and forging workability were evaluated based on the cracks of the product, and an evaluation (△) in the case of enduring use was added.
Fusing characteristics are evaluated by conducting current of 110%, 135%, 150%, 200%, 350%, 600% of the rated current to each test material, measuring the fusing time, and investigating the actual rating and fusing status. The fusing time of 5 seconds or more at an energization rate of 200% was used as a reference.
The temperature rise was evaluated by measuring the temperature of the housing terminal when energizing 100% of the rated current for 1 hour for a rated 25 A fuse, and classifying the good and defective based on the raised temperature of 70 ° C.

  In particular, for Example Alloy 3 showing a standard composition and Comparative Example Alloy 6 corresponding to a conventional fuse material, Table 4 and FIG.

  As described above, Comparative Example Alloy 4 has poor workability and was not subjected to a measurement test. Comparative Example Alloy 5 (pure Zn) has a weak strength and has a problem of strong adhesion to the mold during press working, and the subsequent forging workability studies and measurement tests such as fusing characteristics were not performed. Moreover, the comparative example alloy 2 and the comparative example alloy 6 by the conventional Zn-Cu-Ti alloy were inferior in forge processability. Comparative Example Alloy 1 and Comparative Example Alloy 3 which were processed into fuses and subjected to subsequent tests had slightly lower mechanical strength and characteristics than Comparative Example Alloy 6, and the press alloys and forgeability were also in Examples Alloys 1 to 3. It was slightly inferior to For Example Alloys 1 to 3, there were no problems in strength, press workability and forgeability, and there was no difference between the Example Alloys.

Regarding the fusing characteristics, Comparative Example Alloy 1 and Comparative Example Alloy 2 had poor temperature fusing characteristics because the temperature difference between the liquidus and solidus reached 25 ° C. or more. In addition, the comparative alloy 6 was also susceptible to arcing due to arc discharge during melting.
The temperature rise of Comparative Example Alloy 1 was 85 ° C. and Comparative Example Alloy 6 was 99 ° C., whereas Examples Alloys 1 to 3 of this invention and Comparative Example Alloy 2 and Comparative Example Alloy 3 were 61 ° C. to 65 ° C. In the range, the temperature rise was suppressed.
Also, from Table 4 and FIG. 2, the fusing characteristics of the fuses of the example alloy 3 are different from the characteristics of the fuses of the comparative example alloy 6, and the fusing time becomes longer in the portion where the current ratio is about 150% to about 400%. I understand.

It is a partial state diagram near the eutectic component of a Zn-Al alloy. It is a graph which shows the fusing characteristic of the fuse by the Example alloy of this invention, and the fuse by the conventional comparative example alloy.

Claims (4)

  Changing the Al compounding ratio of a zinc alloy material having a composition containing Al: 3.0-8.0% and Mg: 0.0005-0.06% by weight, with the balance being Zn and inevitable impurities. A method for manufacturing a zinc alloy for fuses, characterized in that the fusing time in the fuse is expanded or reduced.   The composition contains Al: 3.0 to 8.0% and Mg: 0.0005 to 0.06% by weight, the balance being composed of Zn and inevitable impurities, and a liquidus and a solidus A method for producing a zinc alloy for fuses, wherein the fusing time in the fuse is expanded or reduced by changing the Al compounding ratio of the zinc alloy material having a temperature difference of less than 25 ° C. The composition contains Al: 3.0-8.0% and Mg: 0.0005-0.06% by weight, the balance being composed of Zn and inevitable impurities, and a tensile strength of 200 N / mm ² or more. By changing the Al compounding ratio of the zinc alloy material having a hardness Hv of 50 or more, an elongation of 50% or more, an electrical conductivity of 30% IACS or more, and a temperature difference between the liquidus and the solidus of less than 25 ° C. A method for producing a zinc alloy for fuses, wherein the fusing time is expanded or reduced.   The method according to claim 1, wherein the fuse is a normal blown type, a time lag blown type, or a fast acting blown type fuse.

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