JPS63164154A - Tungsten wire for bulb 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] [Objective of the Invention] (Industrial Field of Application) The present invention relates to a W wire that is effective for use in the filament of a light bulb, and more specifically to a W wire that has excellent vibration resistance during high-temperature lighting and prevents deformation of the filament. This invention relates to a W wire for halogen light bulb filaments that does not cause any damage.

(Prior Art) A filament for a light bulb, for example a filament for a halogen light bulb, is usually composed of doped W wire. This doped W wire has a predetermined amount of elements (dopants) such as Si and AM added to it, and has a higher recrystallization temperature than pure W wire, and is elongated in the wire direction at high temperatures. This causes the growth of recrystallized grains, thereby preventing high-temperature deformation due to grain boundary burrs.

In other words, when the halogen bulb is turned on, WI! When L is heated to a high temperature to form a recrystallized structure, the dopant present in a small amount in the W line evaporates and forms a row of fine holes (aligned dope holes) aligned in the axial direction. The doped holes suppress the growth of recrystallized grains in the direction perpendicular to the line axis, increase the recrystallization temperature, and form long recrystallized grains that grow in the line axis direction. Therefore, the resistance of the doped W wire to high temperature deformation is increased.

By the way, when manufacturing such a doped W wire, first a predetermined amount of dopant is added to the W powder, and then this is passed through the forming, sintering, rolling, and wire drawing processes using conventional methods. Depending on the conditions in each process, such as the amount of dopant added, sintering conditions, and the processing rate before processing such as rolling and wire drawing, etc.
The dispersion state of the above-mentioned aligned doped holes changes.

(Problems to be Solved by the Invention) Recently, halogen light bulbs have been used in various lighting fields, but the environment in which they are used has become harsher. Doped W-line filaments, which have traditionally been limited to the south under these conditions, have insufficient vibration resistance when lit, causing problems such as deformation of the filament and uneven light distribution when lit. , there is an increasing demand for the development of W wires that have better vibration resistance when lit.

The object of the present invention is to provide a W wire for a filament of a halogen light bulb, which has been developed to meet the above requirements.

[Structure of the invention] (Means/effects for solving the problem) The present inventors,
In order to achieve the above objective, we closely observed the morphology of the aligned doped holes in the conventional W wire just before coiling into a filament, and found that the diameter of the fine holes constituting the aligned doped holes was approximately 0.1. It is about 0.5-
It has been found that the length of these micropores is approximately 30 mm.

Therefore, the present inventors believe that if the length of the aligned dope holes formed under a certain temperature condition is further increased, in addition to dispersion strengthening of the dope holes, fiber reinforcement by the rows will increase the resistance to high temperature deformation. With the idea that it would be possible to obtain a W wire with excellent vibration resistance during high-temperature lighting, and as a result of various studies, the W wire of the present invention was developed.

That is, when the W wire for the light bulb filament of the present invention has a diameter of 0.39 mm and is subjected to heat treatment for 5 minutes at a temperature of 90% fusing current value, it has a length of 40 mm consisting of micropores. - It is characterized by being arranged and distributed in the above order.

7, the W line of the invention has the greatest feature in the length of the aligned doped holes formed.

This aligned dope hole allows the W wire with a wire diameter of 0.39 mm to be
It is formed when heated for 5 minutes at a temperature corresponding to the % fusing current value. The temperature at this time is approximately 3100℃
It is.

The diameter of each micropore constituting the aligned doped hole is 0.
,5. The following shall apply. Preferably it is 062- or less. If this pore diameter becomes too large, there will be a so-called "°" in the W line.
This is because voids ''' are formed and the mechanical strength is reduced not only at high temperatures but also at room temperature.

Further, the length of the aligned doped holes is 40 μm or more. If this length is too short, the above-mentioned function of the aligned doped holes will deteriorate and high temperature deformation will easily occur. Preferably, the number is 60 or more.

When producing a filament from the W wire of the present invention, the W wire may be further drawn to a predetermined wire diameter, and this may be used for coiling.

(Example of the Invention) A doped W wire with a wire diameter of 0.39 mm was manufactured by a conventional method by changing the amount of dopant added, sintering conditions, and processing rate.

This doped W wire was heated by passing a current corresponding to 90% of the fusing current for 5 minutes in an H2 gas flow.

For each doped W line obtained, its unit length 1 c
m) was cut out and the shape of the aligned doped holes formed therein was observed under a microscope to determine the diameter of the micropores.

The lengths of the aligned doped holes were measured and the average values are shown in the table.

After that, this doped W wire was further drawn to a wire diameter of 20 g.
The diameter was reduced to 7200 m, and this was used to generate 250 W.
Used as filament for halogen light bulbs.

A mounting test was conducted on the copying machine with the halogen bulb turned on, and the degree of deformation of the filament was observed.

The results are shown in the table.

[Effect of the invention] As is clear from the above explanation, W having the conditions of the present invention
The wire does not cause filament deformation when lit at high temperatures and has excellent vibration resistance when lit and not lit, making it useful as a material for filaments for general incandescent bulbs as well as halogen bulbs.

Claims (3)

[Claims] (1) The diameter of the tungsten wire is 0.39 mm, and 90
A tungsten wire for a light bulb filament, characterized in that when subjected to a heat treatment for 5 minutes at a temperature with a fusing current value of %, the tungsten wire can be arranged and dispersed in a length of 40 μm or more consisting of micropores. (2) The tungsten wire for a light bulb filament according to claim 1, wherein the micropores have a diameter of 0.5 μm or less. (3) The tungsten wire for a light bulb filament according to claim 1, wherein the tungsten wire for a light bulb filament is for a halogen light bulb.