JPS5835798B2 - Aluminum snail Aluminum snail - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filler metal for welding aluminum and non-aging aluminum alloys (hereinafter simply referred to as filler metal).

Until now, aluminum-copper system (JIs2oo series), aluminum-magnesium system (JI86000 series) and aluminum-copper-magnesium-zinc system (JI870 series) have been used.
00 series) alloys have high mechanical strength and were widely used as excellent structural materials.

Aluminum alloys generally have poor weldability, and the aforementioned precipitation aging type alloys are particularly prone to weld cracking, and therefore are rarely used as welded structural materials.

If a welded structure cannot be avoided, welding is performed using a co-metal filler metal or an aluminum-silicon alloy filler metal with excellent castability.

When welding is carried out using a matching filler metal, the alloy components increase in the deposited metal, and the concentration of alloying elements decreases in the bond area, resulting in a decrease in strength and the occurrence of weld cracks.

There is A, A alloy salt 4043 as a filler material for aluminum-silicon alloys, but when welding the above-mentioned aging type alloys, weld cracking occurs even though the amounts of silicon, copper, and magnesium are all low. Welding of aged alloys does not cause weld cracking, but there is a drawback that the strength of the welded part is low.

In other words, the reason why weld cracking occurs in aging type alloys is because the high temperature elongation of the filler metal of this alloy is low.

An object of the present invention is to provide a filler metal for welding that does not cause weld cracks and provides a high-strength joint when welding aluminum and non-aging aluminum alloys.

The filler metal of the present invention contains 8 to 15 parts silicon and 0 parts copper by weight.
．． It is an aluminum alloy containing magnesium in an amount of 5 to 3.0 percent and magnesium in an amount of 0.1 to 0.7 percent.

The amount of silicon significantly reduces wear resistance, strength, and high-temperature toughness, resulting in weld cracking, so the upper limit should be set at 1.
It was set at 5%.

In other words, the inventors aimed to prevent weld cracking, which is a shortcoming of already developed aluminum-silicon alloy filler metals, when welding aged aluminum alloys, and to increase the amount of silicon in order to obtain high-strength welds. As a result of research on varying the eutectic over a wide range, it was found that as the proportion of eutectic in the alloy increases, the high-temperature elongation increases, resulting in less weld cracking and higher strength.

Among the aluminum-silicon binary systems, the one with a silicon content of 11.7%, which is the eutectic point, had the highest high-temperature elongation and high-temperature strength.

Moreover, as a result, it was confirmed that the amount of silicon could be given a certain range.

The confirmed amount of silicon was 8 to 15% by weight, and the alloy with this composition range had a eutectic ratio of 68% or more.

A particularly suitable amount of silicon is 9 to 14 by weight, and in this range the proportion of eutectic in the alloy is 75 or more.

As an example, a weld metal of a filler metal containing 8 to 15% silicon by weight and further containing copper, magnesium, etc. within the range of the present invention had a high temperature elongation of 70% or more at 450°C.

That is, the aluminum-silicon two-component system does not provide sufficient strength as a filler material, so copper and magnesium are added to increase the strength.

The amount of copper needs to be 0.5% or more from the viewpoint of strength, and the higher the amount, the greater the effect, but on the other hand, if it exceeds 3.0%, the toughness will decrease and weld cracking will occur, so the upper limit should be set at 3.0%. And so.

In other words, since copper undergoes precipitation aging during the cooling process after welding,
This significantly lowers toughness and causes weld cracking.

Similar to copper, the amount of magnesium is required to be at least 0.1% from the viewpoint of strength, and the higher the amount, the greater the effect, but on the other hand, if it exceeds 0.7%, the toughness will decrease significantly and weld cracking will occur, so the upper limit must be set. was set at 0.7%.

The filler metal of the present invention can be used as a consumable electrode in MIG welding or in TIG welding.
In addition to being used as a bare filler metal in welding and submerged arc welding, it can also be used as a coated arc welding rod.

When used as a coated arc welding rod, it is possible to include some of the alloy components in the coating material.

It can also be used as an insert metal in electron beam welding.

As for the welding means, all methods that can melt the filler metal of the present invention and weld it to the base metal can be applied.

For example, in addition to a series of arc welding such as TIG welding, M-G welding, and submerged arc welding, electron beam welding and the like can be applied.

Furthermore, the filler metal of the present invention can be used for any combination of aluminum or aluminum alloy base materials.

Specifically, a combination of non-aging aluminum alloys,
It can be used for combinations of non-aging alloys and pure aluminum.

That is, welding of dissimilar materials, such as aluminum-based (J I
81000 series) and aluminum-magnesium series (
JI85000 series), but the filler metal of the present invention exhibits favorable effects even in such cases.

The filler metal of the present invention is also significantly superior in workability and machinability compared to previously developed aluminum-silicon alloy filler metals.

Existing aluminum-silicon alloy filler metals were easily scratched on the surface when drawn to be processed into core wire.

Scratches in the core wire entrain the lubricant used when processing the core wire, which is one of the causes of blowholes in the welded metal.

Since the filler metal of the present invention has good workability and does not cause scratches even when drawn, it is possible to prevent blowholes from occurring due to scratches.

In addition, existing filler metals have poor machinability.

Welded joints are usually not cut after welding, but depending on the size of the base metal and the intended use, cutting may be performed after welding.

Previously developed filler metals have poor machinability, making it difficult to finish a smooth surface, but the filler metal of the present invention has good machinability, so it can be easily finished into a smooth surface.

Next, the progress of experiments conducted to determine the composition of the filler metal of the present invention will be explained.

FIG. 1 shows the tensile properties of the deposited metal of aluminum-silicon-copper filler metal.

The amount of silicon is 11% and no magnesium is included.

The tensile test was conducted after the weld metal was treated with T6.

The effect of copper is clear from this figure; copper increases tensile strength but decreases elongation.

FIG. 2 shows the tensile properties of the deposited metal of aluminum-silicon-magnesium filler material after T6 treatment.

The amount of silicon is 11, and there is no copper.

This Figure 2 shows the effect of magnesium, and it was confirmed that the addition of magnesium increases the tensile strength up to 0.6%.

FIG. 3 shows the relationship between the tensile properties and the amount of copper in the deposited metal of a filler metal containing a composite of copper and magnesium.

The amount of silicon is 11% and the amount of magnesium is 0.3%.

This characteristic is after T6 treatment.

Comparing this Figure 3 with Figure 1, the effect of copper when it contains magnesium becomes clear.

It is clear from FIG. 3 that the tensile strength shows the highest value when the copper content is 3%.

Moreover, the value also exceeds 40 kg/am, and it is clear that the properties are equivalent to those of aged aluminum alloys.

FIG. 4 shows the tensile properties of the deposited metal when the copper content is constant and the magnesium content is varied in a filler metal containing both copper and magnesium.

The amount of silicon is 11 more, and the characteristics are the values after T6 treatment.

A comparison with Figure 2 shows the effect of magnesium, and it shows that the maximum tensile strength is found when the amount of magnesium is 0.3%.

Thus, it was confirmed that adding copper and magnesium to an aluminum alloy containing silicon in an amount near the eutectic point increases the tensile strength.

The highest value of tensile strength is when the amount of copper is 3 and the amount of magnesium is 0.
．． 3%, and therefore it is desirable to have amounts of copper and magnesium in the vicinity of this, but not to exceed a factor of 3 in terms of copper content.

When the copper content exceeds a factor of 3, the corrosion resistance becomes extremely poor, and the life of the welded part is therefore significantly shortened.

The lower limit of the amount of copper should be 1% from the viewpoint of strength.

The amount of magnesium is 0.1-0.6%, preferably 0.4
A range of 0.6% to 0.6% is preferable.

If it is less than 0.1%, no significant increase in mechanical strength can be expected, and if it is more than 0.6%, the impact value will drop sharply, making it impossible to correct the distortion of the welded part.

Figure 5 shows aluminum-11 silicon-copper system and aluminum-11 silicon-magnesium system a.
The figure shows the weld cracking rate of butt TIG welding of aluminum-12 polysilicon alloy base material using alloy filler metal.

As shown in the figure, it is recognized that the addition of copper and magnesium a alone makes it easier for weld cracks to occur during welding of aluminum-silicon alloys.

In particular, when the amount of magnesium exceeds 0.7% and the amount of copper exceeds 3%, weld cracking is observed to occur significantly.

Example 1 Silicon 11 parts, magnesium 0.3% and copper 2.5 parts
TIG using an aluminum alloy filler metal containing strips
Non-aging aluminum alloy base materials containing silicon 11 were butt-welded using an AC welding machine.

Also, using the same base material, T
Butt welding was performed using an IG welder.

Welding conditions are welding current 150A, welding voltage 15V, argon gas feed rate 121/vain, welding speed 90-110.
mm/wisteria.

After welding, each sample was subjected to solution treatment by heating at 500°C for 1 hour and aging treatment by heating at 170°C for 10 hours, and then subjected to a tensile test (20°C).

As a result, the tensile strength of the product welded with the filler metal of the present invention was 4
It was observed that the elongation rate of 5.5 kg/mIt1 was significantly higher than that of 8 pull, and no cracking occurred.

In the tensile test described above, all samples fractured at the weld heat affected zone.

Example 4 Using the filler metal of the present invention and the previously developed filler metal, JIS
5083 aluminum-magnesium alloy base material was overlay welded.

The composition of the filler metal is shown in the table.

Welding was carried out using a TIG AC welding machine, with a welding current of 170 A, a welding voltage of 17 cm, and an argon gas feed rate of 15 l, /-i.
The welding speed was 100 to 120 mm/ynin.

Then, a wear test piece was cut out from the overlay weld, and Fe12
A wear test was conducted using the material as a mating material.

The test was conducted using the Okoshi method, and the conditions were a final load of 18
．． 9 to 9, wear distance 600rn1 wear rate 2m/sec
And so.

As a result, the amount of wear according to the present invention is approximately 4
It was 10''-9sit/kg.

From this, it was confirmed that the welded parts according to the present invention were also significantly improved in wear resistance.

As described above, the filler metal of the present invention does not cause weld cracking when welding aluminum and non-aging aluminum alloys.
The excellent effect of obtaining high-strength welded parts was demonstrated.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the tensile properties of aluminum-silicon-copper alloy weld metal and the amount of copper, and Figure 2 is a diagram showing the relationship between the tensile properties and magnesium content of aluminum-silicon-magnesium alloy weld metal. The diagrams shown in FIGS. 3 and 4 are diagrams showing the relationship between the tensile properties of aluminum-silicon-copper-magnesium alloy weld metal and the amount of copper (FIG. 3) and the amount of magnesium (FIG. 4). Figure 5 shows the relationship between the weld cracking rate of the aluminum-silicon alloy base metal and the amount of magnesium and copper in the aluminum-silicon-magnesium alloy filler metal a and the aluminum-silicon-copper filler metal. It is a line diagram.

Claims (1)

[Claims] 1. Aluminum and non-aging aluminum alloy containing 8 to 15% silicon, 1 to 3% copper, 0.1 to 0.7% magnesium, and the remainder consisting of aluminum and accompanying impurities. Filler metal for welding.