JPH03128179A - Resistance welding method using tungsten electrode - Google Patents

Abstract

PURPOSE:To uniformize welding strength and to easily melt members to be welded in a short time by forming plural ruggedness on one member to be welded, superposing it on the other member to be welded and melting the plural ruggedness formed on the one member to be welded to join both members. CONSTITUTION:The plural 16 formed on the member 12 to be welded are abutted on the member 14 to be welded and held between electrode chips 29a and 20b. In this state, the electrode chips 20a and 20b are displaced from the vertical directions and the members 12 and 14 to be welded are pressurized by specified pressurizing force and a specified electric current is applied thereto for a specified time. Heating is continued up to the state just before the plural ruggedness 16 of the member 12 to be welded are molten by utilizing Joule heat and further, the specified mechanical pressure is applied via the electrode chips 20a and 20b. The plural ruggedness 16 of the member 12 to be welded are crushed and both members 12 and 14 to be welded are joined firmly and welding is completed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resistance welding method, and more specifically, when welding members with low electrical resistance and high thermal conductivity (such as copper alloy). This invention relates to a resistance welding method using a tungsten electrode.

[Prior Art] Generally, when welding materials with high melting points (easily brittle, such as molybdenum and tungsten), a metal with a lower melting point than the materials to be welded is used as a filler metal. - Give an example. Ba,
For molybdenum and tungsten, platinum, nickel, etc. are used as filler metals. That is, first, a welding member and a filler metal are brought into contact with each other, and a large current is applied to melt and join the filler metal, and the thus fused and joined filler metal and welding member are heated in the same manner as in the above process. A so-called brazing welding method is used, which consists of a process of fusion joining using the method described above.

[Problems to be Solved by the Invention] However, in the welding method according to the above-mentioned prior art, rare metals are generally used as filler metals, which has the drawback of increasing production costs. ing.

In addition, in the so-called brazing welding method according to the above-mentioned conventional technology, the work process is long and the contact area of each member is large, so the allowable current (allowable power) of the electrode is limited to the upper limit. Since the welding temperature approaches or exceeds , the electrode itself is subject to severe wear and tear, and the electrode and the welding member in contact remain in a welded state and cannot be separated.

Furthermore, when trying to weld two parts together by so-called spot welding, the electrical density becomes diluted and varies, which disrupts the equilibrium state of the converted thermal energy, and furthermore, each Since a current shunting effect occurs between the abutting surfaces of the electrode and the welding member, the welding strength of the welded product varies, which has the disadvantage that it cannot be put to practical use.

The present invention has been made to overcome the above-mentioned disadvantages, and it is possible to shorten the working process, prevent electrode wear, and make the welding strength of the welded product uniform, and at the same time, it is possible to reduce the production cost. An object of the present invention is to provide a resistance welding method that can reduce the

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention forms a plurality of unevenness on one welding member made of molybdenum or tungsten, and forms a plurality of irregularities on one welding member made of molybdenum or tungsten. The other welding member is superimposed, and then the two superimposed welding members are sandwiched between tungsten electrodes and welding current is supplied to melt the plurality of irregularities formed on the one welding member and join the two welding members to the welding member. It is characterized by

[Function] In the resistance welding method using the tungsten electrode according to the present invention configured as described above, one welding member having a plurality of irregularities and the other welding member are overlapped, and these welding members are welded from both directions. By supplying welding current while being held between tungsten electrodes, the welding current is concentrated on the tip of the unevenness, thereby increasing the current density per unit area, melting the unevenness in a short time, and furthermore By applying a pressing force, welding members can be welded together to obtain a welded product with uniform strength.

[Example] Next, a preferred example of a resistance welding method using a tungsten electrode according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a part of a resistance welding apparatus for carrying out a resistance welding method using a tungsten electrode according to the present invention, that is, a welding part and an electrode part.

One welding member 12 and the other welding member 14 are made of, for example, molybdenum, tungsten, or the like.

One welding member 12 can come into contact with the other welding member 14 via a plurality of projections and depressions 16 formed on one surface thereof (see Figure 1). The welding members 12 and 14 stacked in this manner are held between one electrode tip 20a and the other electrode tip 20b, respectively. In this case, the electrode chips 20a and 20b are held by electrode holders 18a and 18b, respectively. The electrode holder 18a and the electrode holder 18b are not particularly limited in terms of material;
Preferably, a copper alloy is used.

On the other hand, the electrode tip 20a and the electrode tip 20b are made of a material that does not cause any problem even if it adheres to the welding member 12.14, and electrode materials other than tungsten are not permitted to be used.

The apparatus for carrying out the resistance welding method using a tungsten electrode according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

First, a case will be described in which a plurality of irregularities 16 are formed on the welding member 12 in the apparatus having the above configuration. The plurality of unevenness 16 is formed by transfer by using a transfer member (not shown) having unevenness harder than the welding member 12, overlapping the transfer member on which part of the welding member 12, and applying a predetermined pressing force. Ru.

Next, the plurality of irregularities 16 formed on the welding member 12 by the above method are brought into contact with the welding member 14, and the electrode tip 20a is brought into contact with the welding member 14.
and sandwiched between the electrode tips 20b. In this state, the electrode tips 20a and 20b are displaced from the top and bottom, and the welding member 12 is
．． 14 is pressurized with a predetermined pressing force, and a predetermined current, e.g., 1 ampere, is passed for a predetermined time, e.g., seconds. As a result, Joule heat expressed by the following equation is generated between the plurality of irregularities 16 formed on the welding member 12 and the welding member 14.

Q=I2Rt [Joule] In this case, Joule heat due to contact resistance generated on the contact surfaces of the welding member 12 and the welding member 14 is used to heat the plurality of irregularities 16 of the welding member 12 to a state just before melting. Then, a predetermined mechanical pressure is applied to the electrode tip 20.
By applying it through holes a and 20b, the plurality of irregularities 16 on the welding member 12 are flattened, and the circumferential welding members 12 and 14 are firmly joined to complete the welding.

In the resistance welding method using the tungsten electrode completed as described above, the welding members 12 and 14 are brought into contact with each other by bringing the plurality of irregularities 16 transferred and formed on the welding member 12 into contact with the welding member 14. Since the contact area is significantly reduced, the resistance generated on this contact surface increases.

Therefore, the amount of heat generated at the contact surface also increases. In other words, the current is concentrated at the tips of the unevenness 16, the current density per unit area is high, and the amount of work per unit time is large, so the tips of the unevenness 16 are easily melted within a short time. It becomes possible. By applying a predetermined pressing force in this state, a nugget 30 can be formed and efficient welding can be completed.

Furthermore, by forming a plurality of irregularities 16 on the welding member 12, the current flowing from the irregularities 16 of the welding member 12 is concentrated at the tips of the irregularities t6, so that the welding strength can be made uniform. .

In addition, compared to conventional construction methods, the present invention does not require temporary fixing of the melting material and welding is completed in one step, resulting in significant effects in terms of work efficiency and manufacturing efficiency.

[Effects of the Invention] As explained above, the present invention has a plurality of irregularities formed on a welding member, brought into contact with the welding member, and supplying a low voltage and large current from an electrode tip, thereby reducing the gap between the respective members. This has the effect of preventing branching of the welding current and making the welding strength uniform, and also increases the contact resistance between the welding members, so that the welding members can be easily melted in a short time. This avoids wear and tear of the electrode tip, prevents mutual welding of the electrode and the welding member, and reduces production costs.

[Brief Description of the Drawings] Fig. 1a is an explanatory diagram showing a welding member and an electrode tip in an apparatus for carrying out a resistance welding method using a tungsten electrode according to the present invention; FIG. 2 is an explanatory view of a state in which welding is completed using the resistance welding method using a tungsten electrode according to the present invention. 12... Welding member ■4... Welding member 16
... Unevenness 18a, 18b... Electrode holder 20a, 20b... Electrode tip 30... Nugget

Claims (2)

[Claims] (1) A plurality of irregularities are formed on one welding member made of molybdenum or tungsten, and the one welding member and
The other welding member made of molybdenum or tungsten is overlapped, and then the two overlapping welding members are sandwiched between tungsten electrodes and welding current is supplied to melt the plurality of irregularities formed on the one welding member. A resistance welding method using a tungsten electrode, which is characterized by joining a welding member. (2) In the resistance welding method according to claim 1, when forming the plurality of irregularities on the one welding member, a transfer member having a plurality of irregularities and made of a harder material than the one welding member is used. A resistance welding method using a tungsten electrode, characterized in that the unevenness is transferred and formed by applying a predetermined pressing force.