JPS63236254A - Tungsten wire for lamp filament - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is for a lamp filament that is used without secondary recrystallization even during lamp flushing.

The present invention relates to a tungsten wire, and more particularly, to a tungsten wire for a lamp filament that has a property that it is difficult for a light bulb filament to break.

(Prior Art) Tungsten (W) filaments are used in various discharge lamps and incandescent light bulbs. This W filament is manufactured by rolling a W sintered body manufactured by a powder metallurgy method, drawing it into a W wire of a predetermined diameter, and coiling the wire.

When a light bulb or the like using the above filament is shipped, it is customary to first energize the filament and subject it to a lamp flushing process. In this case, there are two types of lamp flashing treatments for the filament. One is a method of secondary recrystallization of the W-line crystal structure by lamp flashing treatment, and this treatment is applied to relatively large lamp filaments. The other method is to prevent secondary recrystallization of the W line by lowering the temperature during lamp flashing, and this method is applied to relatively small lamp filaments.

(Problems to be Solved by the Invention) The present application relates to a filament that does not undergo secondary recrystallization even in the latter lamp flushing treatment among the above-mentioned treatments.

If a fine W wire with a low recrystallization temperature is used as a filament for a lamp that generates heat at a high temperature, the secondary recrystallized structure that makes up the filament will tend to become equiaxed grains due to the resistance heat generated during use, and for example, if it is When vibrations or the like are applied, grain boundary sliding occurs in the structure and the filament itself may break. Further, even during transportation of the lamp, if a secondary recrystallized structure is formed in the lighting test, the same disconnection phenomenon may occur.

In order to solve this problem, the filament can be formed from a W thin wire with a high recrystallization temperature.However, such a W thin wire has a high tensile strength, making it extremely difficult to coil the filament. Yes, as a result,
Wire breakage accidents occur frequently during coiling.

The object of the present invention is to provide a W wire for a lamp filament that does not cause any of the above-mentioned problems.

[Structure of the invention] (Means and effects for solving the problems) In order to solve the above-mentioned problems, the present inventors have conducted extensive research on the recrystallization temperature that is effective for filaments, and as a result, a certain recrystallization temperature has been determined. It has been discovered that the W wire is useful against breakage of the filament of a light bulb, as well as against breakage during use and transportation.

That is, in the lamp filament doped W wire used without secondary recrystallization even during lamp flashing of the present invention, the recrystallization temperature is 52 to 60% of the fusing current (FC
) value of temperature.

Here, the FC value refers to the current value required to melt the W wire due to the resistance heat generated when the W wire is energized.
Therefore, the 52% FC value represents the temperature of the W line when a current corresponding to 52% of the FC value is applied to the W line.

The W wire of the present invention has a characteristic that its recrystallization temperature is within the above range. If the FC value is too small, secondary recrystallization is likely to occur, causing grain boundary slippage, resulting in frequent filament breakage during use or transportation.If the FC value is too large, the tensile strength becomes high, causing coiling of the filament. This is because wire breakage accidents are likely to occur. Preferably, it has a recrystallization temperature of 54% FG to 57% FC.

Such a W wire can be manufactured by adopting an appropriate processing rate during processing such as rolling into an ingot and wire drawing.

(Embodiment of the invention) W ingots produced by a conventional method were subjected to rolling and wire drawing at different processing rates, and W ingots with different recrystallization temperatures were obtained.
manufactured the wire.

Using each W wire, 10,000 filaments of 1.5W miniature lamps were manufactured, and the number of filaments that broke during coiling was measured and shown in the table.

Next, a good filament was mounted in a lamp, and a lighting test was performed on all the filaments at the rated power, and the number of disconnections was measured. The results are shown in the table.

Sample 2, which is the W line of the present invention, is Sample 1 shown for comparison.
In comparison with No. 3 and No. 3, wire breakage during coiling and wire breakage during lighting test did not occur, showing good characteristics.

[Effects of the Invention] As is clear from the above description, the W wire of the present invention has fewer disconnection accidents during coiling and fewer disconnection accidents during use, and is suitable for use as a filament.

Claims (1)

[Claims] A doped tungsten wire for a lamp filament which is used without secondary recrystallization even during lamp flashing, and whose recrystallization temperature is a temperature at which the fusing current value is 52 to 60%.