CN1233538A - Method for mfg. ignition alloy for lighter - Google Patents
Method for mfg. ignition alloy for lighter Download PDFInfo
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- CN1233538A CN1233538A CN 98107793 CN98107793A CN1233538A CN 1233538 A CN1233538 A CN 1233538A CN 98107793 CN98107793 CN 98107793 CN 98107793 A CN98107793 A CN 98107793A CN 1233538 A CN1233538 A CN 1233538A
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Abstract
The present invention relates to the prepn. method of kindling alloy for lighter, the process is as follows: melt the raw material metal composition, casting the melted metal in mould, extrude the alloy blank into stick under weak oxidative atmosphere and maintain the weak oxidative atmosphere till the temp. of alloy surface is below 250 deg.C, cut the alloy stick into specified length. The obtd. alloy stick is used to make flint with good weatherability and preservability.
Description
The present invention relates to a method for producing a lighter ignition alloy used for flint, and more particularly to a method for producing a lighter ignition alloy having excellent weather resistance and the like.
The ignition alloy for a lighter is produced by a method (casting method) in which a molten metal obtained by melting a raw material metal is poured into a mold to obtain a rod-shaped cast product, and the rod-shaped cast product is cut into a desired length. However, the production method requires many steps and is low in yield. Therefore, as a rational method, a method (extrusion method) has been developed in which an alloy billet cast from a molten metal is processed into a rod shape by extrusion molding and then cut into a desired length.
Since this extrusion method requires high-temperature and high-pressure extrusion molding, attempts have been made in the past to improve workability during extrusion molding, or to improve ignitability caused by high-temperature and high-pressure treatment. For example, Japanese patent application laid-open No. 55-79851 proposes a method of adding silicon to the alloy composition in order to improve the formability. Jp 52-15773 a proposes a method of controlling the temperature at which the molten alloy solidifies and improving the heat treatment after extrusion molding in order to improve the ignitability of the ignition alloy for a lighter, and jp 55-152106 a proposes a method of producing an ignition alloy for a lighter from a powder raw material by extrusion molding.
In the above extrusion method, it is necessary to heat an alloy containing a large amount of active rare earth metal to 350 to 800 ℃ at the time of extrusion molding, and in the above conventional technique, the atmosphere at the time of extrusion is made vacuum or an inert atmosphere such as a rare gas is formed in order to prevent oxidation of the extruded metal. Such control of atmosphere requires that all the extrusion steps be substantially sealed when the vacuum is achieved, and the apparatus becomes very large, which increases the cost of equipment. On the other hand, when a rare gas atmosphere is formed, an expensive rare gas is used in a large amount, and thus the production cost becomes high. Further, since the surface of the alloy after extrusion molding is clean, the ignition alloy for a lighter manufactured in an inert atmosphere reacts with oxygen, moisture, and the like in the atmosphere to cause oxidation corrosion when left in the atmosphere. Thisoxidation proceeds from the surface of the alloy to the interior of the alloy over time. Therefore, when the flint is stored for a long period of time in a state of being incorporated in a lighter, oxidation corrosion proceeds, and ignition is not possible. In order to solve this problem, measures for suppressing oxidation, such as coating the alloy surface with an expensive anticorrosive paint or the like after extrusion or storing in a vacuum or an inert atmosphere, are necessary, and thus the cost increases.
The present invention aims to provide a method for producing a pyrophoric alloy for flint, which is excellent in weather resistance such as weather resistance and storage stability, at low cost and by a simple method.
According to the present invention, there is provided a method for producing a lighter ignition alloy, comprising the steps of:
a step (a) of melting a raw material metal composition of an ignition alloy for a lighter to form a molten metal;
a step (b) of pouring the molten alloy into a mold to form an alloy billet;
a step (c) of forming a rod-like alloy by extrusion molding the alloy billet; and
a step (d) of cutting the rod-shaped alloy into a predetermined length;
in the step (c), the atmosphere at the time of extruding the rod-shaped alloy is made a weakly oxidizing atmosphere containing an oxidizing gas except oxygen, and the weakly oxidizing atmosphere is maintained at least until the surface temperature of the extruded rod-shaped alloy is lowered to 250 ℃ or lower.
Further, the present invention provides a method for producing a lighter ignition alloy, wherein the weakly oxidizing atmosphere is composed of 10 to 80% by volume of an oxidizing gas consisting essentially of carbon dioxide gas and/or water vapor and 20 to 90% by volume of an inert gas.
Brief description of the drawings
FIG. 1 is a graph showing the results of weathering tests of flint conducted in examples and comparative examples.
The present invention is described in more detail below.
In the production method of the present invention, first, a step (a) of melting a raw material metal composition of an ignition alloy for a lighter to form an alloy melt is performed.
The above-mentioned raw metal composition is not particularly limited as long as it can be used as a raw metal of an ignition alloy for a lighter, but from the viewpoint of the characteristics such as formability, ignitability, weather resistance and the like of the obtained ignition alloy, there can be mentioned a composition disclosed in Japanese patent application laid-open No. Sho 55-79851 and the like, and a composition containing a rare earth metal, iron, magnesium, aluminum and silicon is preferable. Particularly, the composition is preferably one containing 71.0 to 83.5 wt% of misch metal, 15.0 to 25.0 wt% of iron, 0.5 to 4.0 wt% of magnesium, 0.1 to 0.2 wt% of aluminum, and 0.1 to 0.4 wt% of silicon. If the amount of iron is less than 15.0 wt%, the ignitability of the product tends to deteriorate, while if it exceeds 25.0 wt%, the hardness of the obtained pyrophoric alloy increases, and the formability may deteriorate, which is not preferable. When the magnesium content is less than 0.5% by weight, the ignitability of the product may deteriorate, and when it exceeds 4.0% by weight, the formability during extrusion may deteriorate, which is not preferable. If the amount of silicon is outside therange of 0.1 to 0.4 wt%, the moldability during extrusion molding is poor, and thus the composition is unsatisfactory.
In the present invention, the misch metal means an alloy of 2 or more kinds of rare earth metals.
The melting of the raw material metal composition to form an alloy melt is not particularly limited as long as it is a method capable of melting the raw material metal composition at a melting temperature of the mixture of the raw material metals, and a known method can be used.
In the production method of the present invention, the step (b) of pouring the molten alloy into a mold to form an alloy billet is performed next.
The mold for casting the molten alloy may be a mold generally used for producing a lighter ignition alloy by an extrusion method. When the molten alloy is poured into a mold, the mold is usually heated in advance. The heating temperature in this case is not particularly limited as long as it is within the range in which the ignition alloy for a lighter is generally produced by extrusion, but it is preferable that the temperature of the mold is heated to 400 to 800 ℃, particularly 500 to 700 ℃, in view of the characteristics such as formability, ignitability and the like of the produced ignition alloy. When the temperature of the mold is less than 400 ℃, the grain size of the obtained pyrophoric alloy is small and the ignitability is lowered, while when the temperature of the mold exceeds 800 ℃, the life of the mold is reduced and the grain size of the obtained pyrophoric alloy is large, which makes extrusion molding in the step (c) to be described later difficult. Even if the alloy can be extruded, when the resulting pyrophoric alloy is used as a flint to be assembled in a lighter, the friction between the flint and the file wheel during ignition becomes large, and the lighter may malfunction, which is not satisfactory.
In order to form an alloy billet by pouring the molten alloy into a mold, a mold having a desired shape such as a cylindrical shape is used, and the molten alloy may be poured into the mold to form the desired shape, or the molten alloy may be poured into the mold to form the desired shape.
In the production method of the present invention, the step (c) of forming a rod-like alloy by extrusion-forming the alloy billet is performed next. In the step (c), the atmosphere in extruding the rod-shaped alloy is a weakly oxidizing atmosphere containing an oxidizing gas except oxygen, and the weakly oxidizing atmosphere must be maintained at least until the temperature of the surface of the extruded rod-shaped alloy is lowered to 250 ℃ or lower.
In order to extrude the alloy billet, for example, an extrusion molding machine including: an extrusion die having 1 or several passages for shaping the alloy billet into a rod shape; an extrusion die body surrounding the extrusion die body and maintaining a space for placing the alloy billet on the extrusion die; and a punch for pressing the alloy billet so as to extrude the alloy billet through the passage. The pressure conditions during extrusion and the like can be appropriately selected depending on the diameter and length of the passage, the temperature and composition of the alloy billet, and the like. The alloy billet temperature during extrusion molding is preferably 400 to 700 ℃.
The atmosphere of the space surrounding the upper portion of the extrusion die in the extrusion molding is not particularly limited, and may be applied as long as it is an atmosphere that does not react with the alloy billet or, even if it reacts, it reacts only in the surface layer portion of the alloy billet, and does not involve the atmosphere inside. The preferred atmosphere includes a rare gas such as argon, a weakly oxidizing gas such as carbon dioxide gas and/or water vapor, nitrogen, or a mixed gas thereof.
The atmosphere under the extrusion die for extruding the rod-like alloy from the extrusion die passage, i.e., the atmosphere for extruding the rod-like alloy, as described above, must be a weakly oxidizing atmosphere containing an oxidizing gas except oxygen. The oxidizing gas used for forming the weakly oxidizing atmosphere is an oxidizing gas containing no oxygen, and carbon dioxide gas and/or water vapor are preferable. The weakly oxidizing atmosphere is preferably a weakly oxidizing atmosphere consisting essentially of 10 to 80% by volume, preferably 40 to 70% by volume of an oxidizing gas consisting of carbon dioxide gas and/or steam, and 20 to 90% by volume, preferably 30 to 60% by volume of an inert gas such as argon. When the amount of the oxygen-free oxidizing gas is less than 10% by volume in the weakly oxidizing atmosphere, an oxide film cannot be sufficiently formed on the surface of the extruded rod-shaped alloy, and the obtained primer alloy has low weather resistance and storage stability, and the surface of the rod-shaped alloy is smooth, and when a decorative coating needs to be applied to the surface in the subsequent step, the application becomes difficult, which is not preferable. On the other hand, when the mixing amount of the oxygen-free oxidizing gas exceeds 80% by volume, the oxide film on the surface of the rod-shaped alloy to be pressed becomes too thick, pulverization of the film occurs, the weather resistance of the obtained ignition alloy is lowered, and the surface of the rod-shaped alloy is cracked, and the ignitability of the obtained ignition alloy is deteriorated, which is not preferable.
The rod-like alloy extruded from the extrusion die is kept in the weakly oxidizing atmosphere until the surface temperature of the rod-like alloy is lowered to at least 250 ℃ or lower, preferably to 100 ℃ or lower. Further, it is desirable that the extruded rod-like alloy is maintained in a weakly oxidizing atmosphere at least reduced in temperature to a temperature that does not react with oxygen in the atmosphere when the alloy is brought into contact with the atmosphere. When a weakly oxidizing atmosphere is opened in a temperature state in which the surface temperature of the rod-shaped alloy is higher than 250 ℃, the surface of the rod-shaped alloy is excessively oxidized upon exposure to the atmosphere, an oxide film formed on the surface is pulverized, the resulting ignition alloy is deteriorated in resistance to weathering, and the surface of the rod-shaped alloy is cracked, and the resulting ignition alloy is deteriorated in ignitability.
The surface temperature of the rod-like alloy immediately extruded from the passage of the extrusion die or the like is preferably 300 to 700 ℃, particularly 500 to 700 ℃ in consideration of reactivity with the oxidizing gas except oxygen in the weakly oxidizing atmosphere. When the surface temperature of the freshly extruded rod-like alloy is less than 300 ℃, it is difficult to sufficiently react with the oxidizing gas, and an oxide film having an appropriate thickness cannot be formed, so that the obtained pyrophoric alloy may have a low resistance to weathering, and the like, and thus is not satisfactory. On the other hand, when the surface temperature of the rod-shaped alloy just extruded exceeds 700 ℃, the oxide film formed on the surface of the rod-shaped alloy becomes too thick in the above-mentioned weakly oxidizing atmosphere after extrusion, pulverization of the oxide film occurs, the weather resistance and the like of the obtained ignition alloy are lowered, and the surface of the rod-shaped alloy is cracked, and the ignitability of the obtained ignition alloy is lowered, which is not preferable.
The reaction of forming the oxide film formed on the surface of the rod-shaped alloy in theweakly oxidizing atmosphere is performed according to the following reaction formulas (1) and (2) when carbon dioxide gas and/or water vapor is used as the oxidizing gas.
That is, the rare earth metal (R) contained in the extruded rod-shaped alloy reacts with carbon dioxide gas and/or water in a weakly oxidizing atmosphere, and is reduced by the reaction represented by formula (1) and/or formula (2), thereby forming an oxide film on the surface of the rod-shaped alloy.
In general, the method of forming an oxide film on the surface of an alloy can be represented by formula (3), and formula (3) represents a reaction with oxygen.
Here, as the rare earth metal (R), lanthanum is taken as an example, and the generated reaction heat (Δ H1 to Δ H3 in the formula) is Δ H1=945kJ/mol, Δ H2=936kJ/mol, and Δ H3=1794 kJ/mol.
Therefore, when oxygen is contained as the oxidizing gas, the reaction of formula (3) occurs, and in this case, heat generation by oxidation of the alloy is large, so that the reaction proceeds vigorously, and the oxidation spreads to the inside of the alloy. In contrast, in the case where the reaction of the formulae (1) and (2) occurs when carbon dioxide gas and/or water vapor is used as the oxidizing gas not containing oxygen as in the present invention, heat generation due to oxidation of the alloy and heat absorption due to reduction of carbon dioxide gas and/or water are suppressed, so that the reaction does not proceed vigorously and an oxide film can be formed. Therefore, it is considered that since the oxide film formed on the surfaceof the rod-shaped alloy by the reaction represented by the formula (1) and/or the formula (2) is thin, uniform, and dense, when the above-mentioned weakly oxidizing atmosphere is opened, the oxidation wave caused by oxygen and moisture in the atmosphere can be prevented from reaching the inside of the rod-shaped alloy even when the rod-shaped alloy is exposed to the atmosphere, and the obtained ignition alloy is provided with excellent weather resistance, storage stability, and the like.
In the production method of the present invention, the obtained rod-shaped alloy is cut into a predetermined length, and the obtained ignition alloy for a lighter is obtained by performing the step (d). The cutting length is not particularly limited, and may be appropriately selected and selected.
In the production method of the present invention, in addition to the above steps (a) to (d), other steps that are performed in the production of a general ignition alloy for a lighter may be added as necessary within the limits that do not impair the object of the present invention. The surface of the obtained ignition alloy for a lighter may be coated with a decorative coating, an anticorrosive coating, or the like as necessary.
In the method for producing a spark ignition alloy for a lighter according to the present invention, when an alloy billet is extruded to form a rod-like alloy, a specific weakly oxidizing atmosphere is used, so that the obtained spark ignition alloy can be provided with excellent weather resistance, storage stability and the like, and the spark ignition alloy can be produced at low cost.
The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.
Example 1
Raw material metals were mixed in a composition of 77 wt% misch metal, 20 wt% iron, 2.6 wt% magnesium, 0.15 wt% aluminum and 0.25 wt% silicon, and were subjected to atmospheric melting using NaCl as a slag former to form an alloy melt. The alloy melt was brought to 600 ℃ and poured into a cylindrical mold to obtain a cylindrical alloy billet having a diameter of 45 mm. The alloy billet was placed in an extrusion molding machine equipped with an extrusion die, and an argon atmosphere was formed in the upper part of the extrusion die where the alloy billet was placed. Then, a mixed oxidizing gas consisting of 70% by volume of carbon dioxide gas and 30% by volume of argon gas was passed through the lower part of an extrusion die for extruding the alloy billet into a rod-like alloy for 10 minutes to form a weakly oxidizing atmosphere, and then extrusion molding was performed. The surface temperature of the rod-like alloy immediately after being extruded from the lower portion of the extrusion die was 600 ℃ and the surface temperature of the rod-like alloy when it came to the atmosphere from the weakly oxidizing atmosphere zone was 80 ℃.
The resulting rod-shaped alloy was cut into 6mm lengths to prepare a lighter ignition alloy. 15000 pyrophoric alloys were used as flint, and placed in a porcelain dish, and then placed in a constant temperature humidifier with a temperature of 40 ℃ and a humidity of 85% for a weathering test for 50 days. Ignition tests were performed every 10 days to determine the incidence of failure due to weathering. The results are shown in FIG. 1.
Example 2
An ignition alloy for a lighter was produced by extrusion molding under the same conditions as in example 1 except that the mixed oxidizing gas in the lower part of the extrusion die in example 1 was changed to a mixed oxidizing gas composed of 70% by volume of water vapor and 30% by volume of argon gas, anda weathering test was performed. The results are shown in FIG. 1.
Example 3
An ignition alloy for a lighter was produced by extrusion molding under the same conditions as in example 1 except that the mixed oxidizing gas in the lower part of the extrusion die in example 1 was changed to a mixed oxidizing gas composed of 15 vol% of carbon dioxide gas and 85 vol% of argon gas, and a weathering test was performed. The results are shown in FIG. 1.
Comparative example 1
An ignition alloy for a lighter was produced by extrusion molding under the same conditions as in example 1 except that the mixed oxidizing gas in the lower part of the extrusion die in example 1 was changed to argon gas, and weathering test was conducted. The results are shown in FIG. 1.
Claims (3)
1. A method for producing a lighter ignition alloy, comprising the steps of:
a step (a) of melting a raw material metal composition of an ignition alloy for a lighter to form a molten metal,
a step (b) of pouring the molten alloy into a mold to form an alloy billet,
a step (c) of forming a rod-like alloy by extrusion-molding the alloy billet, and
a step (d) of cutting the rod-shaped alloy into a predetermined length,
in the step (c), the atmosphere for extruding the rod-shaped alloy is a weakly oxidizing atmosphere containing an oxidizing gas except oxygen, and the weakly oxidizing atmosphere is maintained at least until the temperature of the surface of the extruded rod-shaped alloy is lowered to 250 ℃ or lower.
2. The method for producing a lighter ignition alloy as claimed in claim 1, wherein in the step (c), the temperature of the alloy billet is set to 400 to 700 ℃ when the alloy billet is extruded.
3. The method for producing a lighter ignition alloy as claimed in claim 1, wherein the weakly oxidizing atmosphere consists essentially of 10 to 80% by volume of an oxidizing gas consisting of carbon dioxide gas and/or water vapor and 20 to 90% by volume of an inert gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98107793A CN1083305C (en) | 1998-04-29 | 1998-04-29 | Method for mfg. ignition alloy for lighter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN98107793A CN1083305C (en) | 1998-04-29 | 1998-04-29 | Method for mfg. ignition alloy for lighter |
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| Publication Number | Publication Date |
|---|---|
| CN1233538A true CN1233538A (en) | 1999-11-03 |
| CN1083305C CN1083305C (en) | 2002-04-24 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN98107793A Expired - Fee Related CN1083305C (en) | 1998-04-29 | 1998-04-29 | Method for mfg. ignition alloy for lighter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102899529A (en) * | 2012-08-13 | 2013-01-30 | 梁建烈 | Pyrophoric alloy and production method |
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| US5153155A (en) * | 1990-12-06 | 1992-10-06 | H. C. Spinks Clay Company Inc. | Clay slurry |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102899529A (en) * | 2012-08-13 | 2013-01-30 | 梁建烈 | Pyrophoric alloy and production method |
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Granted publication date: 20020424 Termination date: 20160429 |