JP3480609B2 - Powder material for aluminum alloy resistance welding, aluminum alloy resistance welding method and aluminum alloy welded structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for welding aluminum alloys.

[0002]

2. Description of the Related Art For example, in order to reduce the weight of a vehicle, the vehicle body may be changed from steel to aluminum alloy. At this time, welding of aluminum alloys is a key point. That is, since aluminum alloy has high electric conductivity and thermal conductivity, it is necessary to flow a large current. Otherwise, the strength of the weld will decrease with respect to the base metal. Especially in spot welding, the strength of the welded part may be 60% or less of the base metal, and as a countermeasure, a method of significantly increasing the current value or increasing the number of welding points is adopted to increase the joint area. There is. However, in order to increase the current value, correspondingly expensive welding equipment is required, and if the number of welding points is increased, the amount of welding work increases and the production cost increases.

Therefore, for example, Japanese Patent Publication No. 54-41550.
Publication "Aluminum Resistance Welding Method", Japanese Patent Publication No. 59-
Technologies such as 26392 "Aluminum resistance welding method" and JP-B-59-26393 "Aluminum resistance welding method" have been proposed.

In the above, the zinc thin film is previously interposed between the aluminum plate and the resistance welding part of the aluminum plate to instantaneously melt zinc during resistance welding to form a local high resistance part and concentrate electric power. Is. The above is a case where the zinc thin film is changed to a Ti thin layer, and the above is a case where the zinc thin film is changed to a stainless steel thin plate.

[0005]

However, although the zinc thin film, the Ti thin layer, and the stainless steel thin plate each have the effect of locally increasing the resistance, they have not yet been able to significantly reduce the required current value. Not in. This is because all the heat required for welding depends on Joule heat. Therefore,
An object of the present invention is to provide a welding material, a welding method, and a welded structure that can improve the bonding strength without increasing the current value.

[0006]

In order to achieve the above object, the present invention provides a nickel oxide powder according to claim 1, wherein
Provided is a powder material for aluminum alloy resistance welding, which is 5% by weight or less and the balance is either one or both of aluminum powder and magnesium powder.

In claim 2, the epoxy resin is 10 to
Provided is a powder material for aluminum alloy resistance welding, the balance of which is nickel powder at 50% by weight.

In claim 3, the epoxy resin is 10 to
Provided is a powder material for aluminum alloy resistance welding, which comprises magnesium powder or a mixed powder of magnesium and aluminum with the balance being 50% by weight.

In claim 4, the epoxy resin is 10 to
A powder material for aluminum alloy resistance welding comprising 50% by weight, 65% by weight or less of a metal oxide, and the balance of either or both of aluminum powder and magnesium powder.

According to a fifth aspect of the invention, the metal oxide is nickel oxide.

In the resistance welding of aluminum alloys according to claim 6, a mixed powder of either one or both of aluminum powder and magnesium powder and nickel oxide powder is welded between the welded parts of the aluminum alloy. A resistance welding method for an aluminum alloy, characterized in that

In claim 7, in resistance welding of aluminum alloys to each other, a liquid resin is further added to a mixed powder of one or both of aluminum powder and magnesium powder and metal oxide powder, and a kneaded product is obtained. Produces
A resistance welding method for an aluminum alloy, characterized in that the kneaded material is interposed between the welded parts of the aluminum alloy. The liquid resin is a liquid resin represented by an epoxy resin or a polyester resin. This kind of liquid resin can be mixed with a curing agent to obtain an adhesive or a molded product.

In the eighth aspect, the liquid resin is an epoxy resin, and the mixing ratio of the epoxy resin is 10 to 50% by weight of the kneaded product.

A ninth aspect of the present invention is an aluminum alloy welded structure formed by resistance welding aluminum alloys together, wherein the nugget portion produced by the resistance welding contains 1 to 20% by weight of nickel.

[0015]

According to the first aspect of the present invention, when welding is performed using a powder material in which nickel oxide powder is mixed with aluminum powder or magnesium powder, thermite reaction of the mixed powder is induced by the resistance heat generation of the powder material, and the amount of heat generation is increased. Can be expanded. Further, nickel is contained in the nugget portion by the thermite reaction with nickel oxide, and a hard Al—Ni-based intermetallic compound can be crystallized in the weld metal portion, and the strength of the welded joint can be improved. Al-Ni
Since the intermetallic compounds are excellent in toughness among the intermetallic compounds, the strength is remarkably improved. If the nickel oxide exceeds 65% by weight, the amount of the aluminum powder or magnesium powder as a reaction partner is small, so that a good reaction does not occur and the nickel oxide remains. Therefore, the proportion of nickel oxide is limited to 65% by weight.

According to a second aspect of the present invention, by including the epoxy resin in the nickel powder for welding, a stable current-carrying portion can be ensured by permeation of the epoxy resin into the contact portion even if the welding pressure is low, and the current-carrying bridge is connected to the electrode. Can be formed in the central portion of the pressurization, and variations in strength can be reduced. This can reduce the pressure applied to the welded portion. Further, the binder action of the epoxy resin prevents the welding powder from scattering and improves the handleability of the welding powder. Further, it is possible to crystallize a hard Al-Ni-based intermetallic compound in the weld nugget to improve the strength. The ratio of epoxy resin is 10% by weight
If it is less than 50% by weight, the viscosity is insufficient, and if it exceeds 50% by weight, the electrical conductivity is deteriorated, which is not preferable. Therefore, the ratio of the epoxy resin is set in the range of 10% by weight or more and 50% by weight or less in terms of both viscosity and electric conductivity.

According to a third aspect of the present invention, a welding powder material is constituted by an appropriate amount of epoxy resin, an appropriate amount of metal oxide, and the like, and magnesium powder or a mixed powder of magnesium and aluminum, and magnesium powder or magnesium and aluminum. The reason why the mixed powder with is used is as follows. That is, when aluminum and magnesium are heated in contact, melting occurs at their eutectic temperature rather than at their individual melting points. In other words, when resistance welding is performed, magnesium or magnesium powder is inserted, and when electricity is applied, melting occurs at 437 ° C., which is lower than the melting point of aluminum. I'm done.

According to a fourth aspect of the present invention, an appropriate amount of epoxy resin, an appropriate amount of metal oxide, and the like are used as a powder material for welding made of aluminum powder or magnesium powder. The epoxy resin gives viscosity to the powder and is easy to handle. Powder material for welding that can enhance the weldability by increasing the temperature of the welded part by promoting the thermite reaction with a metal oxide and further improving the weldability by crystallizing an aluminum or magnesium intermetallic compound. Is.

According to a fifth aspect, the metal powder of the fourth aspect is nickel powder, and the strength of the welding nugget can be improved by nickel.

According to a sixth aspect of the present invention, in resistance welding (spot welding) of aluminum alloys to each other, a mixed powder of either one or both of aluminum powder and magnesium powder and nickel oxide powder is welded to the welded part of the aluminum alloy. Energize while being interposed between them. Then, resistance heat generation induces a thermite reaction of the mixed powder to promote heat generation, and welding at low current becomes possible. In addition, thermite reaction (3NiO + 2Al = 3Ni + Al ₂ O ₃ or Ni
O + Mg = Ni + MgO) allows nickel to be contained in the joint, thereby further increasing the strength of the weld.

According to a seventh aspect, in resistance welding (spot welding) aluminum alloys to each other, liquid resin is further added to a mixed powder of one or both of aluminum powder and magnesium powder and metal oxide powder. A kneaded product is produced by interposing the kneaded product between the welded parts of the aluminum alloy, and a powder of a metal oxide or the like that causes a thermite reaction during welding is viscously held by a thermoplastic resin. , It is possible to keep the energization bridge satisfactorily.

In the eighth aspect, since the liquid resin of the seventh aspect is an epoxy resin, the epoxy resin is hardened and has an action of suppressing the generation of cracks at the ends of the weld nugget, which contributes to the improvement of the joint strength.

A ninth aspect of the present invention is an aluminum alloy welded structure formed by resistance welding aluminum alloys together, wherein the nugget portion produced by resistance welding contains 1 to 20% by weight of nickel. The welded portion of the product has a large strength because nickel is alloyed. If the content of nickel is less than 1% by weight, the crystallization of the intermetallic compound that contributes to the improvement of the strength will be insufficient, and the content of nickel will be 20% by weight.
If it exceeds, the Al matrix disappears to form an intermetallic compound composite phase, so that the effect of toughness becomes strong and the strength improving action becomes insufficient. Therefore, the nugget portion of the welded structure has a nickel content of 1% by weight or more and 2
It should be 0% by weight or less.

[0024]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. In the examples, those for confirming the effect of nickel insert are shown in "Table 1", those for confirming the effect of epoxy resin are shown in "Table 2", and those for confirming the effect of magnesium insert are shown in "Table 3". Summarized in.

Examples 1 to 7 and Comparative Examples 1 to 3 for confirming the effect of nickel insert: Material to be welded (base material); Material: Al-Mg type aluminum alloy (A5182 material)
Rolled material plate thickness: 1.2 mm Electrode: Model: R-type electrode diameter: 16 mm Electrode tip radius: 80 mm Material: Oxygen-free copper welding conditions: Power supply: Inverter system current: Pressurization force as shown in Table 1 below: 400 kgf

[0026]

[Table 1]

In Comparative Example 1, the base materials were directly spot-welded at an electric current value of 18 kA without any insert material,
The tensile shear load was only 198 kgf. In addition, tensile shear load applies shear force to the joint surface by tensile load,
It is the load when the adhesive joint surface breaks. In Comparative Example 2, nickel was inserted at the current value of 18 kA, but the nickel content in the nugget was 25.0% by weight due to the effect of the energization time, which was excessive and the Al matrix disappeared. Since it became the intermetallic compound composite phase, the effect of toughness became strong and the strength improving action became insufficient, and as a result, the tensile shear load was reduced to 92 kgf. Examples 1 to 3
When nickel is used as an insert material while the current value is 18 kA and the base material is spot-welded with the insert material sandwiched, the nickel content in the nugget is 1.0% by weight, 7.8% by weight and 20.0% by weight. %, The tensile shear loads are 223 kgf, 309 kgf and 214 kgf, all exceeding 200 kgf.

In Comparative Example 3, as in Comparative Example 1, no insert material was used and the current was changed to 12 kA.
The tensile shear load is only 160 kgf. Example 4,
5 and 6 are current values of 12 kA and use insert materials made by mixing one or both of nickel oxide and aluminum and magnesium, but the tensile shear load is 278 kgf, 283 kgf and 312 kgf, all 200 kgf Exceeded. Example 7 used an insert in which the amount of nickel oxide was increased to 65% by weight and the balance was aluminum, but the tensile shear load was 298 kgf.
And exceeded 200 kgf.

Examples 8 to 15 and Comparative Example 4 for confirming the effect of epoxy resin: Material to be welded (base material); Material: Al-Mg type aluminum alloy (A5182 material)
Rolled material plate thickness; 1.2 mm Electrode; Format; R-type electrode diameter; 16 mm Electrode tip radius; 80 mm Material; Oxygen-free copper welding conditions; Power supply; Inverter system current; 12 kA Pressurizing force; as shown in Table 2 below

[0030]

[Table 2]

In Comparative Example 4, the base materials were directly spot-welded without the insert material, and the tensile shear load was 1
It was only 60 kgf. Since the current value is smaller than that of Comparative Example 1, the tensile shear load is also small. Example 8 has a suitable amount of N
When the spot welding was carried out at the same current value (12 kA) and applied pressure (400 kgf) of Comparative Example 4, the tensile shear load was 190 kgf.
And increased by 30 kgf. In Example 9, a Ni insert mixed with 25% by weight of an epoxy resin was interposed, and the tensile shear load was significantly increased to 207 kgf. From these facts, the tensile shear load is improved with the Ni insert material than without the insert material, and the tensile shear load is increased with the addition of the epoxy resin in an appropriate amount compared with the Ni insert material alone. Also, because the epoxy resin is mixed, the welding pressure is 100 kgf.
It became smaller, and it was able to be completed with 1/4 of 400 kgf so far. The same applies to the tenth and subsequent embodiments.

Example 10 was prepared by adding an epoxy resin to a mixture of metal oxide powder and magnesium powder.
The tensile shear load was 292 kgf, which was 13 with respect to Comparative Example 4.
It increased by about 2 kgf. In Example 11, an epoxy resin was added to a mixture of a metal oxide powder and an aluminum powder, and the tensile shear load was 289 kgf, which was 129 kgf higher than that of Comparative Example 4. In Example 12, an epoxy resin was added to a mixture of metal oxide powder and aluminum powder, and the tensile shear load was 268 kgf.
It was increased by 108 kgf with respect to Comparative Example 4.

In Example 13, an epoxy resin was added to a mixture of metal oxide powder, magnesium powder and aluminum powder, and the tensile shear load was 299 kgf, which was 139 kgf higher than that of Comparative Example 4. Example 15
Is a mixture of nickel oxide powder, magnesium powder, and aluminum powder, with epoxy resin added,
The tensile shear load was 333 kgf, which was 17 with respect to Comparative Example 4.
It increased by about 3 kgf.

The following can be derived from the results of "Table 1" and "Table 2" above. From Examples 4, 5, 6 and 7 in Table 1, the powder materials for resistance welding according to claim 1 are Comparative Examples 1 and 2.
The better point. From Example 9 in Table 2, the point that the powder material for resistance welding according to claim 2 is superior to Comparative Example 4.

From Examples 10, 11, 12, 13 and 15 of Table 2, the point that the powder material for resistance welding according to claim 4 is excellent. From Example 15 of Table 2, the powder material for resistance welding according to claim 4 is excellent.

From Examples 4, 5, 6 and 7 in Table 1, the resistance welding method according to claim 6 is superior to the methods of Comparative Examples 1 and 2. Examples 10, 11, 12, 13 and 1 of Table 2
5 that the resistance welding method according to claim 7 is excellent.
From Examples 10, 11, 12, 13 and 15 in Table 2, the resistance welding method according to claim 8 is excellent.

From Examples 1, 2, 3, 4, 5, 6 and 7 in Table 1, the aluminum alloy welded structure according to claim 9 is superior to the structures according to Comparative Examples 1 and 2.

Examples 16 to 19 and Comparative Examples 5 and 6 for confirming the effect of magnesium insert: Material to be welded (base material); Material: Al-Mg type aluminum alloy (A5182 material)
Rolled material plate thickness: 1.2 mm Electrode: Model: R-type electrode diameter: 16 mm Radius of electrode tip: 80 mm Material: Oxygen-free copper welding conditions: Power supply: Inverter system current: Pressurizing force as shown in Table 3 below: 400 kgf Or 100 kgf

[0039]

[Table 3]

In Comparative Example 5, a base material was directly spot-welded at a current value of 12 kA without using an insert material,
The tensile shear load was only 160 kgf. Example 1
6 to 18 are 54 wt% Mg-while the current value is 12 kA.
Tensile shear load is 198kgf, 224kgf and 193kg when the base material is spot-welded with the insert material sandwiched between Al and the epoxy resin content of 10wt%, 30wt% and 50wt%.
f, which is over 190 kgf.

In Comparative Example 6, the epoxy resin content was increased to 55% by weight among the conditions of Example 18, and the tensile shear load was 15 due to excess epoxy resin.
It was 8 kgf, which was far below 190 kgf. In Example 19, with the current value kept at 12 kA, Mg was added to 40 wt% epoxy resin as an insert material, and when the base material was spot-welded with the insert material sandwiched, the tensile shear load was 206 kgf and exceeded 190 kgf. It was

From Table 3, the powder material for resistance welding according to claim 3 can obtain a good tensile shear load in spite of a low current value.

[0043]

The present invention has the following effects due to the above configuration. According to claim 1, welding is performed using a powder material in which aluminum powder or magnesium powder is mixed with nickel oxide powder, and the thermite reaction of the mixed powder is induced by the resistance heat generation thereof to increase the amount of heat generation and increase the bonding area. can do. Further, nickel is contained in the nugget portion by the thermite reaction with nickel oxide, and a hard Al—Ni-based intermetallic compound can be crystallized in the weld metal portion, and the strength of the welded joint can be improved.
The Al—Ni-based intermetallic compound is excellent in toughness among the intermetallic compounds, so that the strength is remarkably improved.

According to a second aspect of the present invention, by including the epoxy resin in the nickel powder for welding, it is possible to secure a stable current-carrying portion by permeation of the epoxy resin into the contact portion even when the welding pressure is low, and the current-carrying bridge is connected to the electrode. Can be formed in the central portion of the pressurization, and variations in strength can be reduced. Further, the binder action of the epoxy resin prevents the welding powder from scattering and improves the handleability of the welding powder. Further, it is possible to crystallize a hard Al-Ni-based intermetallic compound in the weld nugget to improve the strength.

A third aspect of the present invention is that the welding powder material is composed of an appropriate amount of epoxy resin, an appropriate amount of metal oxide, and the like, and other powders of magnesium powder or a mixed powder of magnesium and aluminum. The melting point can be lowered by the crystal, and the required amount of heat can be reduced, so that the welding current value can be reduced.

According to a fourth aspect of the present invention, the powder material for welding is composed of an appropriate amount of epoxy resin, an appropriate amount of metal oxide, and the like, and aluminum powder or magnesium powder. Therefore, the epoxy resin gives viscosity to the powder to improve the handling property. The metal oxide can promote the thermite reaction to increase the temperature of the welded portion to improve the weldability, and further crystallize an aluminum or magnesium intermetallic compound to enhance the strength of the welded portion.

Since the metal powder of claim 4 is nickel powder, the strength of the welding nugget can be improved by nickel.

According to a sixth aspect of the present invention, in resistance welding (spot welding) of aluminum alloys, a mixed powder of either one or both of aluminum powder and magnesium powder and nickel oxide powder is welded to the welded part of the aluminum alloy. Since electric current is applied in a state of being interposed between them, thermite reaction of the mixed powder is induced by resistance heat generation, heat generation is promoted, and welding at low current becomes possible. In addition, thermite reaction (3NiO + 2Al = 3Ni + Al ₂ O ₃ or NiO
+ Mg = Ni + MgO), nickel is contained in the joint, and the strength of the weld can be further increased.

According to claim 7, in resistance welding (spot welding) aluminum alloys to each other, liquid resin is further added to a mixed powder of either or both of aluminum powder and magnesium powder and metal oxide powder. A kneaded product is produced by interposing the kneaded product between the welded parts of the aluminum alloy, and a powder of a metal oxide or the like that causes a thermite reaction during welding is viscously held by a thermoplastic resin. , It is possible to keep the energization bridge satisfactorily.

According to the eighth aspect, since the liquid resin of the seventh aspect is an epoxy resin, the epoxy resin is hardened and has an action of suppressing the generation of cracks at the ends of the weld nugget, which contributes to the improvement of the joint strength.

A ninth aspect of the present invention is an aluminum alloy welded structure formed by resistance welding aluminum alloys together, wherein the nugget portion produced by resistance welding contains 1 to 20% by weight of nickel. The welded portion of the product has a large strength because nickel is alloyed.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI // B23K 103: 10 B23K 103: 10 (56) References JP-A-6-122080 (JP, A) JP-A-6-47863 (JP, A) JP 5-5189 (JP, A) JP 63-278679 (JP, A) JP 4-172184 (JP, A) JP 54-41550 (JP, B2) JP JP-B-59-26392 (JP, B2) JP-B-59-26393 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23K 11/18 B23K 35/30

Claims (9)

(57) [Claims] 1. An aluminum alloy resistance welding powder material comprising nickel oxide powder in an amount of 65% by weight or less and the balance of either one or both of aluminum powder and magnesium powder. 2. A powder material for aluminum alloy resistance welding, comprising 10 to 50% by weight of an epoxy resin and the balance being nickel powder. 3. A powder material for aluminum alloy resistance welding, comprising 10 to 50% by weight of an epoxy resin, and the balance being a magnesium powder or a mixed powder of magnesium and aluminum. 4. A powder material for aluminum alloy resistance welding, comprising 10 to 50% by weight of an epoxy resin, 65% by weight or less of a metal oxide, and the balance being either one or both of aluminum powder and magnesium powder. 5. The powder material for aluminum alloy resistance welding according to claim 4, wherein the metal oxide is nickel oxide. 6. When performing resistance welding between aluminum alloys, a mixed powder of one or both of aluminum powder and magnesium powder and nickel oxide powder is prepared.
A resistance welding method for an aluminum alloy, characterized in that it is interposed between the welded parts of the aluminum alloy. 7. When performing resistance welding between aluminum alloys, a liquid resin is further added to a mixed powder of one or both of aluminum powder and magnesium powder and a metal oxide powder to form a kneaded product. A resistance welding method for an aluminum alloy, wherein the kneaded material is interposed between the parts to be welded of the aluminum alloy. 8. The resistance welding of an aluminum alloy according to claim 7, wherein the liquid resin is an epoxy resin, and the mixing ratio of the epoxy resin accounts for 10 to 50% by weight of the kneaded material. Method. 9. An aluminum alloy welded structure obtained by resistance welding aluminum alloys together, wherein the nugget portion produced by resistance welding contains 1 to 20% by weight of nickel. .