JP2005042175A - Aluminum welded structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the strength, toughness and yield strength of a welded metal part and consequently the rigidity of the whole, in a welded structure produced by welding an aluminum alloy material containing 2.0 mass% or more Mg with a melt welding process such as an arc welding process. <P>SOLUTION: This welded structure is produced by butting each other end of two plates 1 and 2 made of an Al-Mg alloy containing 2.7 mass% Mg, and welding them through the double arc welding of forming a molten pool 10 while using simultaneously two MIG welding machines 3a and 3b and two welding wires 4a and 4b. In the above welding, a pure Al wire is used for the welding wire 4a, and an Al-Si alloyed wire is used for the welding wire 4b. In addition, the welded metal part is controlled to have the composition comprising 0.5 mass% or more Si and Mg of a range specified by the expression: 0.3≤(Mg mass%)≤2.5-0.5×(Si mass%). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an aluminum welded structure manufactured by welding an aluminum alloy material containing 2.0 mass% or more of Mg by a fusion welding method such as arc welding.

  Al-Mg-based aluminum alloy materials containing 2.0% by mass or more of Mg have excellent mechanical properties and good corrosion resistance and weldability. Therefore, they are suitable for general welded structures such as ships and railway vehicles. Widely applied. Various fillers such as pure Al, Al—Cu alloy, Al—Si alloy, Al—Mg alloy, etc. are used as the filler material (welding rod or welding wire) when the aluminum alloy material is melt welded. Defined by JIS. However, since strength and toughness are generally required for welded structures, in JIS Z3604, a filler material made of an Al-Mg alloy is used as a filler material when welding an Al-Mg aluminum alloy material. (5000 series in JIS Z3232) is recommended (see, for example, Patent Document 1). The reason for this is that when a filler material made of pure Al (1000 series in JIS Z3232) is used when welding an Al—Mg-based aluminum alloy material, the strength of the weld metal part is weakened, and the Al—Cu-based alloy is used. When a filler material (2000 series in JIS Z3232) is used, the weld cracking sensitivity of the weld metal part increases and the corrosion resistance of the weld metal part deteriorates, so that the filler metal (4000 in JIS Z3232) is made of an Al—Si alloy. This is because the strength and toughness of the weld metal part are lowered when the system) is used.

JP 2000-288773 A

  However, the conventional techniques described above have the following problems. When an aluminum welded structure is manufactured by welding an Al-Mg alloy material using a filler material made of an Al-Mg alloy, the strength of the weld metal part is increased, but the yield strength is not improved, and the mother It becomes the same level as the material. For this reason, when a force is applied to the aluminum welded structure, the weld metal portion where stress is likely to concentrate is deformed with a relatively low stress. As a result, the rigidity of the entire welded structure is lowered.

  The present invention has been made in view of such a problem, and in a welded structure manufactured by welding an aluminum alloy material containing 2.0 mass% or more of Mg by a fusion welding method such as arc welding, The problem that the strength and toughness of the weld metal part when welding with a filler material made of Al-Si alloy of the present invention is low, and the relatively low when welding with a filler material made of conventional Al-Mg alloy Solves the problem that the weld metal part deforms due to stress and the rigidity of the entire welded structure is lowered, and provides an aluminum welded structure that has high strength, toughness and proof strength of the weld metal part and high rigidity as a whole. For the purpose.

The aluminum welded structure according to the present invention includes a base material portion made of an aluminum alloy containing 2.0 mass% or more of Mg, 0.5 to 4.5 mass% of Si, and a composition range defined by the following mathematical formula. Mg is contained, and the balance is composed of Al and inevitable impurities. Among the inevitable impurities, Fe: 0.8% by mass or less, Cu: 0.3% by mass or less, and Zn: 0.25 It is regulated to not more than mass%, and has a weld metal part that joins the base material parts or joins the base material part to another member. In the following formula, “Mg” and “Si” indicate the contents of magnesium (Mg) and silicon (Si) in the weld metal part, respectively.
0.3 ≦ Mg (mass%) ≦ 2.5−0.5 × Si (mass%)

  Another aluminum welded structure according to the present invention is defined by a base material part made of an aluminum alloy containing 2.0% by mass or more of Mg, 0.5 to 4.5% by mass of Si, and the above formula. Mg in the composition range is contained, Zr: 0.01 to 0.3% by mass, Ti: 0.01 to 0.2% by mass, B: 0.001 to 0.02% by mass, Mn: 1. 0% by mass or less, Cr: containing one or more elements selected from the group consisting of 0.35% by mass or less, the balance having a composition consisting of Al and inevitable impurities, among the inevitable impurities, Fe: 0.8% by mass or less, Cu: 0.3% by mass or less, and Zn: 0.25% by mass or less, and the base material parts are joined to each other or the base material part is replaced with another base material part. And a weld metal part to be joined to the member.

Moreover, it is preferable that the composition of the said weld metal part satisfy | fills the following numerical formula.
0.3 ≦ Mg (mass%) ≦ 2.5−0.6 × Si (mass%)

Furthermore, it is more preferable to satisfy the following mathematical formula.
2.2-1.4 × Si (mass%) ≦ Mg (mass%)

  In the present invention, by specifying the Si and Mg contents in the weld metal part within the above-described range, the strength and toughness of the weld metal part that is the joint part can be increased and the proof stress can be increased. Thereby, even when a force is applied to the aluminum welded structure, the weld metal portion is hardly deformed, and the rigidity of the entire aluminum welded structure is improved.

  Furthermore, the aluminum welded structure includes a second filler made of a first filler material containing 99.00% by mass or more of Al and an Al—Si based alloy containing 4.0% by mass or more of Si. The base material portions or the base material portions may be welded to other members using materials simultaneously.

Alternatively, the aluminum welded structure contains 1.0 to 4.0% by mass of Si and Mg having a composition range defined by the following formula, and Zr: 0.05 to 0.3% by mass, Ti : 0.05 to 0.2 mass%, B: 0.001 to 0.02 mass%, Mn: 1.0 mass% or less, Cr: one or more selected from the group consisting of 0.35 mass% or less The balance is composed of Al and inevitable impurities, and among the inevitable impurities, Fe: 0.8 mass% or less, Cu: 0.3 mass% or less, and Zn: 0.25 mass% or less The base material portions or the base material portions may be welded to other members using a filler material regulated in the above.
Mg (mass%) ≦ 2.5-0.5 × Si (mass%)

  Furthermore, the aluminum welded structure may be a vehicle suspension frame or a two-wheeled vehicle frame.

  As described above in detail, according to the present invention, in an aluminum welded structure in which an aluminum alloy material containing 2.0 mass% or more of Mg is welded, the contents of Si and Mg in the weld metal part are appropriately defined. By doing, the strength, toughness, and proof stress of a weld metal part can be made high. Thereby, a weld metal part becomes difficult to deform | transform and the rigidity of the whole aluminum welded structure improves.

  In order to solve the above-described problems, the present inventors have investigated in detail the relationship between the composition of the weld metal part and the joint strength. As a result, in the weld metal part which is a joint part, the Si content is increased more than the weld metal part formed when welding using a filler material made of a conventional Al-Mg alloy, and It has been found that by reducing the Mg content, the proof stress of the weld metal part is improved and hardened, and when an external force is applied to the aluminum welded structure, the weld metal part is hardly deformed. In addition, in the weld metal part formed when welding using a filler material made of a conventional Al-Si alloy, the Si content of the weld metal part becomes too much than the optimum range, It has been found that the weld metal part becomes too hard and the fracture strength of the welded joint decreases.

  Therefore, as a result of repeated earnest experimental studies, the present inventors have solved the above-mentioned problems when welding an aluminum alloy material containing 2.0% by mass or more of Mg as a base material to produce an aluminum welded structure. In order to increase the stress (0.2% proof stress) that causes not only the fracture strength of the welded joint but also 0.2% permanent elongation and increase the rigidity of the entire welded structure, The Si content is 0.5 to 4.5 mass%, and the Mg content is 0.3 ≦ Mg (mass%) ≦ 2.5−0.5 × Si (mass%). I found out that welding should be done. Further, it is better to weld so that the composition of the weld metal part is 0.3 ≦ Mg (mass%) ≦ 2.5-0.6 × Si (mass%), 2.2-1.4 × It has been found out that Si (mass%) ≦ Mg (mass%) ≦ 2.5−0.6 × Si (mass%) is even better.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. First, a first embodiment of the present invention will be described. In the aluminum welded structure according to the present embodiment, first and second base metal parts made of an aluminum alloy are provided. The aluminum alloy forming the base material part is an alloy containing 2.0% by mass or more of Mg, for example, an alloy specified by A5454 of JIS H4000, Mg is 2.7% by mass, and Mn is 0. .6% by mass, 0.1% by mass of Cr, and the balance is an alloy having a composition composed of Al and inevitable impurities. The base material portion is a plate-like member having a thickness of, for example, 3 mm and a tempering of, for example, an O material.

  And this 1st and 2nd base material part is welded mutually, and the weld metal part which is a joint part is formed between the 1st base material part and the 2nd base material part. Yes. The weld metal part contains 0.5 to 4.5% by mass of Si and is defined by a mathematical formula (0.3 ≦ Mg (% by mass) ≦ 2.5−0.5 × Si (% by mass)). Mg is contained in an amount, and the balance consists of Al and inevitable impurities. Inevitable impurities may include Fe, Cu, and Zn. The content of these components is Fe: 0.8 mass% or less, Cu: 0.3 mass% or less, and Zn: It is 0.25 mass% or less. Further, the weld metal part includes a second filler composed of a first filler material containing 99.00% by mass or more of Al and an Al—Si based alloy containing 4.0% by mass or more of Si. It is welded using the material at the same time.

  Hereinafter, the reason for the numerical limitation in each constituent requirement of the present invention will be described.

Mg content of base material part: 2.0 mass% or more Mg is effective in improving weldability as well as improving tensile strength, yield strength and toughness when added to an aluminum material. When the content of Mg in the base material part is less than 2.0% by mass, the above-described effects are insufficient, so the Mg content in the base material part is set to 2.0% by mass or more.

Si content of weld metal part: 0.5 to 4.5% by mass
When the Si content of the weld metal part is less than 0.5% by mass, the yield strength of the weld metal part is lowered and the metal weld part is easily deformed, and the rigidity of the entire aluminum welded structure is lowered. On the other hand, when the Si content of the weld metal part exceeds 4.5% by mass, the strength and toughness of the weld metal part decreases. Therefore, the Si content of the weld metal part is set to 0.5 to 4.5% by mass.

Mg content of weld metal part: 0.3 to (2.5-0.5 × Si (mass%)) mass%
If the Mg content in the weld metal part is less than 0.3% by mass, the tensile strength, proof stress and toughness of the weld metal part are insufficient. On the other hand, if the Mg content of the weld metal part is greater than (2.5-0.5 × Si (mass%)), that is, the value of (Mg (mass%) + 0.5 × Si (mass%)) is If it exceeds 2.5, the proof stress of the weld metal part is reduced, and it becomes easy to deform. Therefore, the Mg content of the weld metal part is set to 0.3 to (2.5-0.5 × Si (mass%)) mass%. The Mg content in the weld metal part is more preferably in the range of 0.3 to (2.5-0.6 × Si (mass%)), and 2.2-1.4 × Si (mass). %) ≦ Mg (mass%) ≦ 2.5−0.6 × Si (mass%).

Zr content of weld metal part: 0.01 to 0.3% by mass
Ti content of weld metal part: 0.01 to 0.2% by mass
B content of weld metal part: 0.001 to 0.02 mass%
Mn content of weld metal part: 1.0% by mass or less
Cr content of weld metal part: 0.35 mass% or less Zr, Ti, B, Mn and Cr have an effect of refining crystal grains by adding to the aluminum filler metal. Moreover, there exists an effect which improves tensile strength and elongation. However, when the content in the weld metal part is less than Zr: 0.01% by mass, Ti: less than 0.01% by mass, and B: less than 0.001% by mass, the effect of refining crystal grains is small. On the other hand, when Zr is added in excess of 0.3% by mass, Ti is added in excess of 0.2% by mass, B is added in excess of 0.02% by mass, Mn is 1.0% by mass. When added in excess of%, when Cr is added in excess of 0.35 mass%, there is a risk that the weld metal part becomes brittle. For this reason, the weld metal part has a Zr content of 0.01 to 0.3% by mass, a Ti content of 0.01 to 0.2% by mass, a B content of 0.001 to 0.02% by mass, It is preferable to contain one or more elements selected from the group consisting of Mn content: 1.0 mass% or less and Cr content: 0.35 mass% or less. Thereby, the ductility of a welding part improves.

Fe content in weld metal part: 0.8% by mass or less
Cu content of weld metal part: 0.3 mass% or less
Zn content of weld metal part: 0.25% by mass or less In addition, Fe, Cu, Zn, etc. may be inevitably mixed as other components, but Fe: 0.8% by mass or less, Cu : 0.3 mass% or less, Zn: 0.25 mass% or less, there is no practical problem.

  Next, the manufacturing method of the aluminum welded structure according to this embodiment configured as described above will be described. FIG. 1 is a perspective view showing a method of welding an aluminum alloy material in the present embodiment. As shown in FIG. 1, first, two plate materials 1 and 2 are prepared as materials to be welded. The thicknesses of the plate materials 1 and 2 are, for example, 3 mm, the refining is an O material, and the plate materials 1 and 2 are formed of an aluminum alloy containing 2.0 mass% or more of Mg. This aluminum alloy is, for example, an alloy specified by alloy number A5454 of JIS H4000, and the composition thereof includes 2.7% by mass of Mg, 0.6% by mass of Mn, and 0.1% by mass of Cr. The balance consists of Al and inevitable impurities.

  Next, the end portions of the two plate members 1 and 2 are butted together, butt-welded by arc welding, and joined together. Instead of butt welding, overlapped fillet welding may be performed. At this time, two arc welding is performed by using two welding wires 4a and 4b at the same time and forming one weld pool 10 by two MIG welders 3a and 3b.

  The welding machine 3a is provided with a cylindrical contact tip 5a made of a conductor and holding the welding wire 4a, and the welding wire 4a is inserted through the inside of the contact tip 5a. Further, the welding machine 3a is provided with a wire feeding device 6a for supplying the welding wire 4a toward the contact tip 5a. Furthermore, a power source 7a is connected to the contact tip 5a and the plate member 1, and the power source 7a supplies a welding current to the welding wire 4a via the contact tip 5a. Similarly, the welding machine 3b is provided with a contact tip 5b, a wire feeding device 6b, and a power source 7b. And the welding machines 3a and 3b are provided with the one nozzle 8 in common. The welding wires 4a and 4b are inserted into the nozzle 8 so as to be supplied to a predetermined welding position in the vicinity of the butted portion between the plate material 1 and the plate material 2, and as a shielding gas from the nozzle 8, for example, 100% argon gas is injected.

  Further, as the welding wire 4a, a welding wire made of pure aluminum containing 99.00% by mass or more of Al, for example, a 1000 series welding wire such as A1100 defined in JIS Z3232, is used. On the other hand, the welding wire 4b includes, for example, a welding wire made of an Al—Si alloy containing 4.0 mass% or more of Si, for example, 4.5 mass% or more, for example, 4000 series such as A4043 defined in JIS Z3232. Use welding wire. The diameter of the welding wires 4a and 4b is, for example, 1.2 mm.

  Furthermore, the welding current passed through the welding wires 4a and 4b is, for example, 105 to 255 kA. The welding voltage is, for example, 20 to 28 V, the welding wire feed rate is, for example, 5 to 16 m / min, and the welding speed is, for example, 1.5 m / min. Under such conditions, the welding machines 3a and 3b generate arcs 9a and 9b at the abutting portion between the plate material 1 and the plate material 2 to form one molten pool 10, respectively. And the bead 11 is formed in the butt | matching part of the board | plate materials 1 and 2 by moving the position of the arcs 9a and 9b relatively with respect to the board | plate materials 1 and 2, and the board | plate material 1 and the board | plate material 2 mutually. Join. At this time, the bead 11 becomes a weld metal part. The composition of the weld metal part is a composition in which the plate materials 1 and 2 and the welding wires 4a and 4b are mixed, contains 0.5 to 4.5% by mass of Si, and has a formula (0.3 ≦ Mg (% by mass)). The composition contains Mg in an amount specified by ≦ 2.5−0.5 × Si (mass%). Thereby, the above-mentioned aluminum welded structure can be formed.

  In the present embodiment, welding may be performed by connecting the welding wires 4a and 4b to a single welding power source, and the welding wires 4a and 4b are brought close to each other (twisted), so that one A welding wire may be used, and arc welding such as TIG welding or MIG welding may be performed using this one welding wire. Further, a welding wire containing Si in the range of 1.0 to 4.0% by mass and Mg (2.5-0.5 × Si (mass%)) or less is prepared, and this welding wire is used alone. May be used for arc welding. Further, laser beam welding may be performed while supplying the welding wire to the molten pool.

  Next, a second embodiment of the present invention will be described. 2 is a perspective view showing the suspension frame of the automobile according to the present embodiment, and FIG. 3 is a cross-sectional view taken along the line A-A ′ shown in FIG. 2. As shown in FIGS. 2 and 3, the aluminum welded structure according to this embodiment is a suspension frame for automobiles. In this suspension frame 21, support members 22 and 23 are provided. The support members 22 and 23 are curved rod-like members, and openings 25 are formed at both ends.

  Two pipe members 26 and 27 are provided so as to fix the support members 22 and 23 to each other. That is, one end of the pipe members 26 and 27 is welded to the support member 23, and the other end of the pipe members 26 and 27 is welded to the support member 24. Each of the pipe members 26 and 27 is formed into a pipe shape by bending two plate members each having a plate thickness of, for example, 3 mm into a U shape, and overlapping and welding the both end portions thereof. That is, for example, the pipe member 26 is formed by two plate members 26a and 26b, and the pipe member 27 is formed by two plate members 27a and 27b. Accordingly, the pipe members 26 and 27 are formed with two weld beads 28 in parallel to the axial direction thereof. A weld bead 29 is formed at the joint between the pipe members 26 and 27 and the support members 22 and 23.

  The support members 22 and 23 and the pipe members 26 and 27 are made of an aluminum alloy containing 2.0% by mass or more of Mg. The composition of each welded portion, that is, the weld beads 28 and 29, is 0.5 to 4.5 mass% Si and a mathematical formula (0.3 ≦ Mg (mass%) ≦ 2.5−0.5 × Si Mg in the composition range defined by (mass%)), Zr: 0.01 to 0.3 mass%, Ti: 0.01 to 0.2 mass%, B: 0.001 to 0 0.02% by mass, Mn: 1.0% by mass or less, Cr: One or more elements selected from the group consisting of 0.35% by mass or less, with the balance being Al and inevitable impurities. For example, the composition further satisfies the above formula (2.2-1.4 × Si (mass%) ≦ Mg (mass%)). Inevitable impurities may include Fe, Cu, Zn, and the like. The contents of these components are Fe: 0.8% by mass or less, Cu: 0.3% by mass or less, And Zn: It is 0.25 mass% or less.

  Next, a method for manufacturing the automobile suspension frame 21 according to the present embodiment will be described. First, bending or pressing is performed on a plate material made of an aluminum alloy containing 2.0% by mass or more of Mg and having a plate thickness of 3 mm, for example, to form U-shaped plate materials 26a, 26b, 27a, and 27b, respectively. To do. On the other hand, the support members 22 and 23 are formed by an extrusion method, a casting method, or a forging method, and openings 25 are formed at both ends thereof.

  Next, pre-welding treatment such as degreasing and cleaning is performed on the plate members 26a, 26b, 27a and 27b, and the support members 22 and 23. Next, the plate members 26a and 26b are installed on a jig, or are tack-welded and fixed to each other so that the ends are in contact with each other. Then, main welding is performed, and the plate members 26 a and 26 b are welded to each other to form the pipe member 26. At this time, the welding method is overlap fillet welding by AC pulse MIG automatic welding, and welding is performed using one welding wire. This welding wire contains 1.0 to 4.0% by mass of Si and Mg having a composition range defined by the above formula (Mg (% by mass) ≦ 2.5−0.5 × Si (% by mass)). Zr: 0.05 to 0.3% by mass, Ti: 0.05 to 0.2% by mass, B: 0.001 to 0.02% by mass, Mn: 1.0% by mass or less, Cr : Containing at least one element selected from the group consisting of 0.35% by mass or less, the balance consisting of Al and inevitable impurities, and among the inevitable impurities, Fe: 0.8% by mass or less, Cu : 0.3% by mass or less, and Zn: 0.25% by mass or less.

  Further, the welding speed is, for example, 600 mm / min, the shielding gas composition is, for example, 100% argon, the shielding gas flow rate is, for example, 25 liters / minute, the welding current is, for example, 130 to 150 A, and the welding voltage is, for example, 19 to 21 V. The polarity (EN) ratio is, for example, 30%.

  As a result, both end portions of the plate material 26a and both end portions of the plate material 26b are joined to each other to form the tubular pipe member 26. At this time, a weld bead 28 is formed in the weld. Further, the dilution rate of the weld bead 28, that is, the ratio of the base metal melted part in all the weld metal parts (the weld metal welded part and the base metal melted part) (base metal melted part / (fused material welded part + base metal melted part)). Part)) is, for example, 10 to 80%, and the composition of the weld bead 28 is 0.5 to 4.5% by mass of Si and a formula (0.3 ≦ Mg (% by mass) ≦ 2.5−0.5. × Si (mass%)) containing Mg in the composition range defined by Zr: 0.01 to 0.3 mass%, Ti: 0.01 to 0.2 mass%, B: 0.001 Thru | or 0.02 mass%, Mn: 1.0 mass% or less, Cr: It contains 1 or more types of elements selected from the group which consists of 0.35 mass% or less, The remainder consists of Al and an unavoidable impurity, Among the inevitable impurities, Fe: 0.8 mass% or less, Cu: 0.3 mass% or less, and Zn: 0.25 It becomes the composition is less than the amount%, for example, the composition further satisfying the above equation (2.2-1.4 × Si (wt%) ≦ Mg (mass%)). Similarly, the pipe member 27 is formed by welding the plate material 27a and the plate material 27b to each other.

  Next, the pipe members 26 and 27 and the support members 22 and 23 are installed on a jig or are tack-welded so that one end portions of the pipe members 26 and 27 come into contact with the support member 23 and the pipe members 26 and 27 The other end portions are fixed to each other so as to contact the support member 24. Then, main welding is performed, one end portions of the pipe members 26 and 27 are welded to the support member 23, and the other end portions of the pipe members 26 and 27 are welded to the support member 24 to form the automobile suspension frame 21. At this time, the welding method is the same as the welding method when the pipe member 26 is formed. As a result, the composition of the weld bead 29 is the same as the composition of the weld bead 28.

  Thereby, in this embodiment, the strength, proof stress, and toughness of a weld metal part are all excellent, and the suspension frame for motor vehicles with high rigidity can be obtained. The effects of the present embodiment other than those described above are the same as those of the first embodiment described above.

  Next, a third embodiment of the present invention will be described. 4 is a perspective view showing a frame of the two-wheeled vehicle according to the present embodiment, and FIG. 5 is a cross-sectional view taken along line B-B ′ shown in FIG. 4. As shown in FIGS. 4 and 5, the aluminum welded structure according to the present embodiment is a frame for a two-wheeled vehicle (motorcycle).

  The frame 31 is provided with a pipe member 32 curved in a horseshoe shape, and two support members 33 and 34 are joined to both ends of the pipe member 32. A connecting member 35 is joined between the support members 33 and 34. The connecting member 35 is a columnar member, one end of which is joined to the support member 33, and the other end of the support member 34. It is joined to. An annular frame is formed by the pipe member 32, the support members 33 and 34, and the connecting member 35. Further, a tubular member 36 is joined to the outer surface side of the annular frame at the longitudinal center portion of the pipe member 32.

  The pipe member 32 is formed by joining both end portions of two U-shaped plate members 32a and 32b to each other by fillet welding. In addition, a joint portion between the plate member 32a and the plate member 32b in the pipe member 32, a joint portion between both ends of the pipe member 32 and the support members 33 and 34, a joint portion between the support members 33 and 34 and both ends of the connecting member 35, A weld bead 37 is formed at the joint between the pipe member 32 and the cylindrical member 36.

  The pipe member 32, the support members 33 and 34, the connecting member 35, and the cylindrical member 36 are formed of an aluminum alloy containing 2.0% by mass or more of Mg. The composition of each welded portion, that is, the weld bead 37, is 0.5 to 4.5 mass% Si and a formula (0.3 ≦ Mg (mass%) ≦ 2.5−0.5 × Si ( Mg) in the composition range defined by (mass%))), Zr: 0.01 to 0.3 mass%, Ti: 0.01 to 0.2 mass%, B: 0.001 to 0.00. It contains one or more elements selected from the group consisting of 02% by mass, Mn: 1.0% by mass or less, and Cr: 0.35% by mass or less, and the balance is made of Al and inevitable impurities, and the inevitable Among impurities, Fe: 0.8% by mass or less, Cu: 0.3% by mass or less, and Zn: 0.25% by mass or less. For example, a formula (2.2-1.4 × Si (Mass%) ≦ Mg (mass%)). The method for manufacturing the motorcycle frame 31 according to the present embodiment is the same as the method for manufacturing the vehicle suspension frame 21 according to the second embodiment.

  In the present embodiment, it is possible to obtain a two-wheeled vehicle frame that is excellent in strength, proof stress, and toughness of the weld metal part and has high rigidity. The effects of the present embodiment other than those described above are the same as those of the first embodiment described above.

  Hereinafter, the effect of the embodiment of the present invention will be specifically described in comparison with a comparative example that deviates from the scope of the claims. First, Example 1 will be described. FIG. 6 is a plan view and a side view showing the specimens after welding in this example and the comparative example. FIG. 7 shows the Si content of the weld metal part on the horizontal axis and the weld metal part on the vertical axis. It is a graph which shows the composition range of the weld metal part in this invention taking Mg content of.

  By the method described in the above-described embodiment of the present invention, two aluminum alloy plates are overlapped and welded using two welding wires by the double MIG welding machine (tandem MIG welding machine) shown in FIG. A lap fillet joint 12 as shown in FIG. 6 was produced. As shown in FIG. 6, in the overlapped fillet joint 12, the end portions of two plate members having a width of 250 mm are overlapped with each other with an overlap margin of 10 mm, and the end portion of one plate member and the other end portion of the other plate member are overlapped. A weld metal portion 13 is formed on the surface of the plate material. The length of the lap fillet joint 12 is 190 mm.

  In this welding, the wire feed amount is in the range of about 7 to 14 m / min by making the composition of the welding wire different for each specimen or by making the welding current of the welding machine different for each specimen. The composition of the weld metal part 13 was made different from each other. The diameter of the welding wire is 1.2 mm, and the welding wire is one of 1000 series (pure Al series), 4000 series (Al-Si series) and 5000 series (Al-Mg series) welding wires defined in JIS Z3232. Selected from. Further, as a base material, a plate material which is an aluminum alloy plate specified by A5454 of JIS H4000, a plate thickness of 4.0 mm, and a tempered material is an O material. Table 1 shows the welding conditions per welding machine. Moreover, the composition of the used base material and the welding wire is shown in Table 2, and the welding conditions are shown in Table 3. The symbols described in the “wire type” column shown in Table 3 correspond to the “JIS symbols” shown in Table 2.

  And after producing the lap fillet joint 12 as shown in FIG. 6, the No. 5 test piece prescribed | regulated by JIS Z2202 was cut out from the lap fillet joint 12 so that the weld metal part 13 might become a test part. . Next, using this No. 5 test piece, a joint tensile test was performed so that the gauge distance (GL) was 50 mm, and the mechanical properties of the weld metal part 13 were evaluated. In addition, the value of 0.2% proof stress was employ | adopted for the value of YS (proof strength). Moreover, the component analysis of the weld metal part 13 was performed, and the relationship between the composition of the weld metal part 13 and the mechanical property of a joint was investigated. Furthermore, the cross-sectional shape of the weld metal part 13 was investigated, and the approximate dilution rate of the base material was measured. These results are shown in Table 4 and FIG.

  A region 41 shown in FIG. 7 indicates a composition range defined in claim 1 of the present invention, a region 42 indicates a composition range defined in claim 2 of the present invention, and a region 43 is defined in claim 3 of the present invention. The composition range is shown, and the region 44 shows a composition range that is outside the composition range of the present invention. Further, the straight line 45 represents the mathematical formula (Mg = 2.5−0.5 × Si), the straight line 46 represents the mathematical formula (Mg = 2.5−0.6 × Si), and the straight line 47 represents the mathematical formula (Mg). = 2.2-1.4 × Si). A region 41 is a right triangle region surrounded by a straight line 45, a straight line Mg = 0.3, and a straight line Si = 0.5, and a region 42 is a straight line 46, a straight line Mg = 0.3, a straight line Si = 0. 5 is a right-angled triangular region, the region 43 is a rectangular region surrounded by a straight line 46, a straight line 47, a straight line Mg = 0.3, and a straight line Si = 0.5, and the region 44 is a region. It is an area other than 41. That is, the region 43 is inside the region 42, and the region 42 is inside the region 41. Furthermore, the numbers surrounded by circles shown in FIG. 7 are plots showing the compositions of the examples and comparative examples, and the numbers in the circles are the experiment Nos. Shown in Tables 3 and 4. The position where the circle is shown indicates the Si content and Mg content of the weld metal part of each example or comparative example. Furthermore, in the column of “Evaluation” in Table 4, when TS is 140 MPa or more, “TS: ○ (good)” is set, and when TS is less than 140 MPa, “TS: x (defect)” is set, and YS Was set to “YS: ○ (good)”, and the case where YS was less than 90 MPa was set to “YS: × (defect)”. Furthermore, “area” shown in Table 4 indicates an area where each example and comparative example are plotted in FIG.

  Of the Examples and Comparative Examples of the present invention shown in Table 4, Example No. 1 to 6, the Si content of the weld metal part is 0.5 to 4.5% by mass, and the Mg content is in the range of 0.25 to (2.5-0.5 × Si (mass%)). Therefore, both strength and proof stress were high. In contrast, Comparative Example No. 7 to 15, the Si content of the weld metal part is less than 1% by mass, the Si content is more than 4.5% by mass, or the Mg content of the weld metal part is less than 0.3% by mass. Or more than (2.5-0.5 × Si (mass%)), at least one of strength and proof stress was low. In addition, Example No. shown in Table 4 1 to 6 and Comparative Example No. 1 Among the compositions of the weld metal parts in 7 to 15, the compositions other than Si and Mg satisfied the range defined in claim 1 or 2 of the present invention.

  Next, Example 2 will be described. FIG. 8 is a plan view and a side view showing a longitudinal back bending test piece after welding in the present example and the comparative example. In the same manner as in Example 1 described above, two aluminum alloy plates were butt welded using a double MIG welder (tandem MIG welder) shown in FIG. 1 to produce a butt joint. did.

  In this welding, the groove shapes of the butt portions were made different from each other, whereby the dilution ratios of the base materials were made different from each other, and the compositions of the weld metal portions were made different from each other. The diameter of the welding wire is 1.2 mm, and the welding wire is one of 1000 series (pure Al series), 4000 series (Al-Si series) and 5000 series (Al-Mg series) welding wires defined in JIS Z3232. Selected from. Further, as a base material, a plate material which is an aluminum alloy plate specified by A5454 of JIS H4000, a plate thickness of 4.0 mm, and a tempered material is an O material. Furthermore, the surplus on the front and back surfaces were removed after welding. Table 5 shows the composition of the base material and the welding wire used, and Table 6 shows the welding conditions. The symbols described in the “wire type” column shown in Table 6 correspond to the “JIS symbols” shown in Table 5.

  And after producing the butt joint as mentioned above, the vertical back bending test piece as shown in FIG. 8 was produced. As shown in FIG. 8, the vertical back bending test piece 14 has a rectangular shape with a short side of 80 mm and a long side of 100 mm, and a center part in the short side direction is butt welded to form a weld metal part 15. Has been. A roller bending test with a bending radius R of 10 mm was performed on the vertical back bending test piece 14, and the presence or absence of cracks was evaluated. The number of tests was three (n = 1, 2, 3) for each condition. Moreover, the composition of the weld metal part 15 was analyzed, and the relationship between the composition of the weld metal part 15 and the toughness of the joint was investigated. Furthermore, the cross-sectional shape of the weld metal part 15 was investigated, and the approximate dilution rate of the base material was measured. These results are shown in Table 7. In the column of “Vertical Back Bending Test Result” in Table 7, the case where no crack occurred was indicated as “◯”, and the case where a crack occurred was indicated as “X”. The “region” shown in Table 7 is the No. shown in Table 7. When 21 to 28 are plotted in FIG. 7, the regions where these plots are located are shown. However, in FIG. 21 to 28 are not plotted.

  Of the Examples and Comparative Examples of the present invention shown in Table 7, Example No. 21 to 24, the Si content of the weld metal part is 0.5 to 4.5% by mass, and the Mg content is 0.3 to (2.5−0.5 × Si (mass%)). The toughness was good because it was inside. In Examples 21 to 23, the Mg content is in the range of (2.2-1.4 × Si (mass%)) to (2.5-0.6 × Si (mass%)). The toughness was particularly good. In contrast, Comparative Example No. Nos. 25 to 28 had poor toughness because the Si content in the weld metal part was less than 1% by mass or the Mg content was higher than (2.5-0.5 × Si (mass%)). . In addition, Example No. shown in Table 7 21 to 24 and Comparative Example No. Among the compositions of the weld metal part in 25 to 28, the compositions other than Si and Mg satisfied the range defined in claim 1 or 2 of the present invention.

It is a perspective view which shows the welding method of the aluminum alloy material which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the suspension frame of the motor vehicle based on the 2nd Embodiment of this invention. It is sectional drawing by the A-A 'line | wire shown in FIG. It is a perspective view which shows the frame of the two-wheeled motor vehicle which concerns on the 3rd Embodiment of this invention. It is sectional drawing by the B-B 'line shown in FIG. It is the top view and side view which show the test material after the welding in an Example and a comparative example. It is a graph which shows the composition range of the weld metal part in this invention, taking Si content of a weld metal part on a horizontal axis, and taking Mg content of a weld metal part on a vertical axis | shaft. It is the top view and side view which show the vertical back bending test piece after the welding in an Example and a comparative example.

Explanation of symbols

1, 2; Plate material 3a, 3b; MIG welder 4a, 4b; Welding wire 5a, 5b; Contact tip 6a, 6b; Wire feeding device 7a, 7b; Power source 8; Nozzle 9a, 9b; Bead 12; overlapped fillet joint 13; weld metal part 14; vertical back bending test piece 15; weld metal part 21; suspension frame 22, 23; support member 25; opening 26, 27; pipe member 26a, 26b, 27a 27b; Plate material 28, 29; Weld bead 31; Frame 32; Pipe member 32a, 32b; Plate material 33, 34; Support member 35; Connection member 36; Cylindrical member 37; Weld bead 41; Composition range)
42; region (composition range defined in claim 2)
43; region (composition range defined in claim 3)
44; region (composition range deviating from claim 1)
45; straight line (Mg = 2.5-0.5 × Si)
46; straight line (Mg = 2.5-0.6 × Si)
47; straight line (Mg = 2.2-1.4 × Si)

Claims (8)

A base material part made of an aluminum alloy containing 2.0% by mass or more of Mg, 0.5 to 4.5% by mass of Si and Mg having a composition range defined by the following formula, with the balance being Al and inevitable Among the inevitable impurities, Fe: 0.8% by mass or less, Cu: 0.3% by mass or less, and Zn: 0.25% by mass or less, An aluminum welded structure comprising: a base metal part, or a weld metal part that joins the base metal part to another member.
0.3 ≦ Mg (mass%) ≦ 2.5−0.5 × Si (mass%) Containing a base material part made of an aluminum alloy containing 2.0% by mass or more of Mg, 0.5 to 4.5% by mass of Si, and Mg having a composition range defined by the following formula, and Zr: 0.01 to 0.3% by mass, Ti: 0.01 to 0.2% by mass, B: 0.001 to 0.02% by mass, Mn: 1.0% by mass or less, Cr: 0.35% by mass It contains one or more elements selected from the group consisting of the following, and the balance has a composition consisting of Al and inevitable impurities. Among the inevitable impurities, Fe: 0.8 mass% or less, Cu: 0 .3% by mass or less, and Zn: 0.25% by mass or less, and having a weld metal part that joins the base material parts or joins the base material part to another member. Aluminum welded structure characterized by
0.3 ≦ Mg (mass%) ≦ 2.5−0.5 × Si (mass%) The aluminum welded structure according to claim 1 or 2, wherein the Mg content of the weld metal part satisfies the following mathematical formula.
0.3 ≦ Mg (mass%) ≦ 2.5−0.6 × Si (mass%) The aluminum welded structure according to claim 3, wherein the Mg content of the weld metal part satisfies the following mathematical formula.
2.2-1.4 × Si (mass%) ≦ Mg (mass%) A first filler material containing 99.00% by mass or more of Al and a second filler material consisting of an Al—Si based alloy containing 4.0% by mass or more of Si are used at the same time. 5. The aluminum welded structure according to claim 1, wherein the metal parts or the base material part is welded to another member. 1.0 to 4.0% by mass of Si and Mg having a composition range defined by the following mathematical formula are included, and Zr: 0.05 to 0.3% by mass, Ti: 0.05 to 0.2% by mass %, B: 0.001 to 0.02 mass%, Mn: 1.0 mass% or less, Cr: one or more elements selected from the group consisting of 0.35 mass% or less, with the balance being Al And a filler material regulated by Fe: 0.8% by mass or less, Cu: 0.3% by mass or less, and Zn: 0.25% by mass or less among the inevitable impurities. The aluminum welded structure according to any one of claims 1 to 4, wherein the base metal parts or the base metal parts are welded to another member.
Mg (mass%) ≦ 2.5-0.5 × Si (mass%) The aluminum welded structure according to any one of claims 1 to 6, wherein the aluminum welded structure is an automobile suspension frame. The aluminum welded structure according to any one of claims 1 to 6, wherein the welded aluminum structure is a frame of a motorcycle.

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