JPH08118031A - Weld bond method - Google Patents

Abstract

PURPOSE: To maintain joining strength of structure by means of joining strength of nugget in the case of non-heat treatment and deterioration of adhesive by welding while a material to be welded is heated prior to entering into pressurizing action. CONSTITUTION: An adhesive 3 of epoxy, etc., is sandwiched between materials 1, 2 to be welded of aluminum alloy sheet, etc., resistance welding is done while pressurizing with electrodes 4, 5. And then with use of hot air blowing devices 6, 7, materials 1, 2 to be welded are heated to 50-170 deg.C before entering into working action and welded. Heating is done by infrared lamp. By this method, the cooling of materials 1, 2 to be welded due to the adhesive 3 is prevented so as to assist generation of good nugget. In the case of <50 deg.C, the cooling due to the adhesive 3 is not prevented, on the other hand, in the case of >170 deg.C, the adhesive 3 of thermosetting is reacted to be hardened/ degenerated, good joining strength is not obtained even by subsequent heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved weld bond method for resistance welding via an adhesive.

[0002]

2. Description of the Related Art Generally, the weld bond method is applied to assembly of structures, for example, resistance welding of two or more plates through an adhesive, and then heat treatment under the condition that the adhesive hardens. This is a joining method in which the adhesive is cured by application to obtain high strength. In the weld bond method, high strength can be obtained by heat treatment to cure the adhesive, but the strength in the case of non-heat treatment is low enough not to reach the strength of ordinary resistance welding. Therefore, the resistance welding in the conventional weld bond method has been intended to be carried out for the purpose of temporary fixing and for supporting the structure up to the heat treatment step. As a result of various investigations by the present inventors, the reason why the strength at the time of non-heat treatment is not obtained is that resistance heat is absorbed by the adhesive due to the intervention of the adhesive, and the heat quantity until the material to be welded is melted. However, the welding operation ends and the fusion is poor, and at the same time, the internal quality of the nugget is inferior to that of general resistance welding, so that the strength cannot be obtained. On the contrary, it was found that when the current value was increased so that the nugget could be sufficiently produced, the welding of the electrode and the material to be welded occurred.

On the other hand, regarding the future application of the weld bond method, the strength of the nugget when not heat treated is high,
Further, it is desired to further improve the strength of the nugget in consideration of a peeling accident due to a change with time of the adhesive after the heat treatment. By the way, the weld bond method is disclosed in JP-A-59-
There is a method disclosed in Japanese Patent No. 193773. In this method, a thermoplastic resin spacer is contained in the adhesive, the spacer is melted by heating, and the adhesive is removed by pressurization to improve the adhesion between the materials to be welded. However, in this method, a spacer is required, and there is a problem that the apparatus becomes complicated, such as using an auxiliary electrode for the heating means. In addition, as a heating type welding method using electrodes, Japanese Patent Publication No.
The method disclosed in Japanese Laid-Open Patent Publication No. 6-4353 has a structure in which 80
It is a method of locally heating by an electrode through a fluid of ℃ ~ 150 ℃, because the fluid in the electrode by spot welding is for cooling in order to prevent heating of the electrode itself,
The spot welding method using a fluid such as the above temperature has a problem that the electrodes are adversely affected and proper welding cannot be performed.

[0004]

As a result of studying the above-mentioned problems, the present invention can obtain a necessary nugget strength even if an adhesive is interposed by a simple method. Therefore, the strength of the nugget in the non-heat treatment can be improved. The weld bond method has been developed that can secure the strength and can maintain the necessary strength of the structure by the bonding strength of the nugget even when the adhesive strength of the adhesive decreases due to aging.

[0005]

The present invention is characterized in that, in a weld bond method in which resistance welding is performed through an adhesive, the material to be welded is heated to 50 to 170 ° C. and welded before the pressing operation is started. The weld bond method according to claim 1 is defined as claim 1, the heating is performed by hot air, the weld bond method according to claim 1 is defined as claim 2, and the heating is performed by an infrared lamp. The weld bond method according to claim 1 is defined as claim 3.

[0006]

In the ordinary weld bond method, as described above, since the adhesive is interposed between the materials to be welded, the resistance heat is absorbed by the adhesive, resulting in poor fusion. However, in the present invention, By heating the material to be welded to 50 to 170 ° C. before starting the pressurizing operation as described above, the material to be welded is prevented from being cooled by the adhesive and the production of a good nugget is promoted. The heating temperature of 50 to 170 ° C. is that cooling by an adhesive cannot be prevented at less than 50 ° C.
Also, if the temperature exceeds 170 ° C., the thermosetting adhesive reacts and is hardened or deteriorated, and good bonding strength cannot be obtained even by the subsequent heat treatment.

As the above heating means, a method of blowing hot air onto the material to be welded or a method of irradiating an infrared lamp can be applied as a simple method. Further, as resistance welding, it is effective for any welding machine such as a single-phase AC welding machine, a single-phase rectification welding machine, an inverter welding machine, etc., and the electrodes used are conventionally used such as chromium copper, chromium-zirconium copper, etc. If the material is present, it is enough. Further, as the adhesive, any of thermosetting epoxy, acrylic, urethane and phenol adhesives which have been conventionally used in the weld bond method are effective. Further, the material to be welded is effective in any case of aluminum alloy, rolled steel plate, plated steel plate and the like.

[0008]

EXAMPLES An example of the present invention will be described below. (Embodiment 1) FIG. 1 is a diagram showing an outline of a weld bond method according to an embodiment of the present invention. Reference numerals 1 and 2 are materials to be welded such as an aluminum alloy plate, 3 is an adhesive such as an epoxy-based material, and 4 is an adhesive.
Reference numerals 5 and 5 are electrodes, and reference numerals 6 and 7 are hot air blowing devices. The above welded material is A5182P-O material, and the size is 1.0
An aluminum alloy plate of mmt × 25 mm × 100 mm is used, an epoxy type adhesive is used, and the thickness is 0.8.
mm, coating area 25 mm × 25 mm, two sheets were lapped, and one-point spot welding was performed at the center. The welding machine is a single-phase rectification welding machine, the electrode is chrome copper φ16mm, integrated type R
A shape (R = 80 mm) was used. The welding current was 24 kA, the applied pressure was 3923 N, the energization time was 5 cy, and the heating was carried out by blowing hot air onto the material to be welded at the start of welding to reach a predetermined temperature. The number of welds is 5, JIS is the criterion
Z3140 Class B tensile shear strength average value (2083
N) and B class nugget diameter average value (4.5 mm) were used.
In addition, for the tensile test, we conducted the unheated one,
The nugget diameter was measured on the test piece after the tensile test. The results of these welding tests are shown in Table 1. The evaluation criteria in the table are based on the following criteria. ◎ Both the tensile shear strength and the nugget diameter satisfy the JIS B class standard values (2083N, 4.5 mm). Δ Both tensile shear strength and nugget diameter satisfy only JIS B class standard values (2083N, 4.5 mm). × Neither the tensile shear strength nor the nugget diameter satisfies the JIS B class standard values (2083N, 4.5 mm). Further, the tensile shear strength and the nugget diameter are average values of 5 pieces.

[0009]

[Table 1]

As is clear from Table 1, the No.
All of 1 to No. 4 sufficiently satisfy the judgment reference value of 2083N. On the other hand, Comparative Example No. 5 has a low heating temperature, and No. 6 has a high heating temperature.
Since o.7 does not heat, neither of them satisfies 2083N.

(Embodiment 2) FIG. 2 is a view showing the outline of another example of the weld bond method according to an embodiment of the present invention.
Reference numerals 2 and 2 are materials to be welded such as aluminum alloys, 3 is an adhesive such as urethane adhesive, 4 and 5 are electrodes, and 8 and 9 are infrared lamps. The above-mentioned welded material is A5052P-O, the size is 0.8 mmt × 25 mm × 100 mm aluminum alloy, the adhesive is urethane type, the thickness is 1.5 mm, and the coating area is 25 mm × 25 mm. The sheets were lapped and spot welding was performed at the center. The welding machine is a single-phase AC welding machine, and the electrode is DR type of chromium-zirconium copper φ16mm cap tip (6φ, 40R).
Was used. Welding current is 24kA, pressure is 3923N,
The energization time was set to 5 cy, and the heating was performed by irradiating the material to be welded with an infrared lamp at the start of welding and performing welding when the temperature reached a predetermined level. The number of welds is 5, JIS Z314 is used as a criterion
0 Class B tensile shear strength average value (1103N) and Class B nugget diameter average value (4.5 mm) were used. The tensile test was carried out on unheated ones, and the nugget diameter was measured on the test piece after the tensile test. The results of these welding tests are shown in Table 2. The evaluation criteria in the table are based on the following criteria. ◎ Both the tensile shear strength and the nugget diameter satisfy the JIS B class standard value (1103N, 4.0 mm). Δ Both the tensile shear strength and the nugget diameter satisfy only the JIS B class standard value (1103N, 4.0 mm). C. Both the tensile shear strength and the nugget diameter do not satisfy the JIS B class standard values (1103N, 4.0 mm). Further, the tensile shear strength and the nugget diameter are average values of 5 pieces.

[0012]

[Table 2]

As is clear from Table 2, No.
All of 1 to No. 4 sufficiently satisfy the judgment reference value of 1103N. On the other hand, Comparative Example No. 5 has a low heating temperature, and No. 6 has a high heating temperature.
Since o.7 does not heat, neither of them satisfies 1103N.

[0014]

According to the present invention as described above,
A good nugget can be obtained even if an adhesive is present, and therefore, the necessary bonding strength can be maintained even when the heat treatment is not performed and when the adhesive is deteriorated, which is a significant industrial effect.

[Brief description of drawings]

FIG. 1 is a schematic view of a weld bond method according to an embodiment of the present invention.

FIG. 2 is a schematic view of another example of the weld bond method according to the embodiment of the present invention.

[Explanation of symbols]

 1, 2 Material to be welded 3 Adhesive 4,5 Electrode 6,7 Hot air blowing device 8,9 Infrared lamp

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Oguri 7-1 Akita-cho, Takatsuki-shi, Osaka Sunstar Giken Co., Ltd. (72) Kiichi Yamashita 7-1 Akita-cho, Takatsuki-shi, Osaka Sunstar Giken Co., Ltd.

Claims (3)

[Claims] 1. In a weld bond method in which resistance welding is performed via an adhesive, 50 to be welded material is applied before starting a pressurizing operation.
Weld bond method characterized by heating to ~ 170 ° C and welding. 2. The weld bond method according to claim 1, wherein the heating is performed by hot air heating. 3. The weld bond method according to claim 1, wherein the heating is performed by an infrared lamp.