JPS63247334A - Aluminum alloy for extrusion having excellent surface smoothness - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to an aluminum alloy for extruded materials that is suitably used in applications that require surface smoothness, such as decorative materials and blank tubes for photosensitive drums in dry copying machines. .

Conventional techniques and problems Generally, when aluminum or aluminum alloy is extruded from a billet, as the extrusion speed increases, the heat generated during extrusion, especially the frictional heat between the extruded material and the bearing surface of the die, causes the aluminum or aluminum alloy to die. It is known that the phenomenon of adhesion (seizing) occurs, and this adhesion has an adverse effect on the surface smoothness of the extruded material. For this reason, the extrusion speed is limited, or the extruded material needs to be subjected to finishing treatments such as cutting, puff polishing, or chemical polishing, which are factors that hinder productivity improvement.

Conventionally, in order to deal with such problems, for example,
Publication No. 8546 proposes that by adding 0.005 to less than 0.02% of B to an Afi-Mg-5i alloy, a sufficient extrusion speed can be obtained without impairing the surface condition of the extruded material. In addition, in Japanese Patent Publication No. 54-4267, B-B e between the billet and the die during extrusion molding.
A proposal has been made to achieve the same objective as described above by interposing an aluminum alloy containing at least one of the following elements: sTi, ZrSW%Mo, and V.

However, in the former case, the amount of B added should be 0°005~
The content is less than 0.02%, and within this added amount range, it is not possible to obtain a satisfactory effect, that is, a satisfactory surface smoothness. In the latter case, the B content of the aluminum alloy intervening piece is 0°003 to 0.500%, and the Be content is 0.
03 to 0.50%, it is not only impossible to obtain a sufficiently satisfactory surface smoothness, but also an aluminum alloy intervening piece is interposed between the billet and the die. Therefore, in order to produce a uniform effect over the entire length and circumference of the extruded material, extremely advanced on-site technology is required, which is extremely difficult to implement.

In view of the above-mentioned problems, this invention aims to provide an aluminum alloy for extrusion with an improved composition in order to increase the extrusion speed and obtain even better surface smoothness. be.

Means for Solving the Problems This invention effectively prevents aluminum from adhering to the extrusion die by including a considerable amount of B in the aluminum alloy and uniformly dispersing hard borides. This was achieved through this knowledge.

Therefore, the gist of the present invention is to provide an aluminum alloy for extrusion, which basically contains B in a range of 0.5 to less than 10%, with the balance being aluminum and unavoidable impurities, and has excellent surface smoothness.

Furthermore, the present invention also covers extruded materials to which various elements are added to improve the properties in relation to the properties required for the use, such as wear resistance and mechanical properties, depending on the specific use of the extruded material. As a target aluminum alloy with such required properties, in addition to the above B content of 0.5 to less than 10%, St: 0.05 to 13% Fe: 0.05 to 2% Cu: 0.05-7% Zn: 0.05-8% Mn: 2% or less Mg: 7% or less Cr: 1% or less Ti: 0.5% or less Zr: 0.5% or less Rare earth elements: 0.5- 10% Pb: 1% or less Bi 11% or less Ni: 0.05-6% V: 0.1-10% Co: 0.1-10% Contains one or more of the following, and the remainder is Al. and unavoidable impurities.

The feature of this invention is that, as mentioned above, B is added and contained in a significantly larger amount than the range known in the prior art. This high content of B forms an intermetallic compound with Al in the extruded material, and this compound, ie, boride, has an excellent cleaning effect on the bearing surface of the die, and the aluminum on the bearing surface is This prevents the adhesion of the material, improves the surface smoothness of the extruded material, and makes it possible to increase the extrusion speed.

If the content of B is less than 0.5%, the above-mentioned effects intended by the present invention cannot be sufficiently achieved. But 1
When the content is high, such as 0% or more, the effect is saturated, but the tool abrasion properties deteriorate and the die wear becomes severe. The most suitable B content is in the range of 0.5 to less than 5%.

Additional elements other than B S i s Fe - Cu s Z
n sMn, Mg, Cr, Ti, Zr, rare earth elements, Pb, Bl, Ni, V, and Co may be optionally used alone or in combination of two or more to improve properties in relation to the use of the extruded material. It can contain additives.

5iSFe s Cu % Zn SMn s Mg mainly improves mechanical properties, and Si, F
Both of e s Cu s Z n have no effect when contained less than 0.05%, and St; 13%, Fe; 2%, C
When the content exceeds u: 7%, Zn: 8%, Mn: 2%, and Mg: 7%, combined with the high content of B, coarse crystallized substances are produced, resulting in performance deterioration. invite

Both Cr ST1 and Zrs rare earth elements are added to stabilize the composition and refine crystal grains. All of them can be effective even when added in small amounts, but in the case of rare earth elements, it is necessary to add 0.5% or more in order to obtain the desired effect. However, Cr; 1%, Ti: 0.5%, Zr:
The effect is saturated at 0.5% and rare earth element: 10%, and adding more than that is harmful in that it generates coarse crystallized substances in the alloy and deteriorates the mechanical properties.

In addition, rare earth elements have atomic numbers of 15 to 57 to 71.
Elements, namely La, Ce, Pr5Nd-PmS
S m 1E u SGd 1Tb s D y 1H
It consists of a group of 17 elements: o -E r , T rAlY b SL u 1, and y and Sc added to these. These elements do not necessarily have to be used as individual elements, and Mitsushi metal obtained by electrolyzing mixed chlorides of rare earth metals may also be used.

YSLaSCe is used industrially because it is easy to handle manually.

One or two selected from the group Pr5Nd, Sm
It is preferable to use a combination of two or more species.

Pb, Bl provide lubricity to the alloy and improve formability, and both have effects when added in small amounts, but at 1%
Adding more than that is actually harmful.

N 1 % V 1Co mainly contributes to improving heat resistance. Ni: less than 0.05%, V: 0
．． If it is less than 1% and Co: less than 0.1%, the effect cannot be obtained, but the upper limit of the allowable content is N1::6%, V:10
%, Co: 10%, and if the content exceeds this, the mechanical properties will deteriorate.

Effects of the Invention As described above, this invention uniformly disperses a hard boride in an aluminum alloy by adding and containing a prescribed amount of B, and during extrusion molding, this boride is deposited on an extrusion die. Because it has a cleaning effect that immediately removes
Furthermore, it is possible to obtain an extruded material with excellent surface smoothness over the entire circumference and entire length. Therefore, not only can productivity be increased by improving extrudability, but also extruded materials can be cut, puffed, and polished for products that require surface smoothness.
Alternatively, it is possible to eliminate the need for post-finishing treatment steps such as chemical polishing, thereby simplifying the manufacturing process.

Example Aluminum alloys having various compositions shown in Table 1 were melted and cast into billets at an extrusion temperature of 500°C and an extrusion speed of 0. 357
Under extrusion conditions of FL/sin, the outer diameter is 44 mm and the inner diameter is 371 mm.
It was extruded into 1IIIl tubing.

And the surface smoothness (gloss) of the extruded material after a certain amount of extrusion.
Then, we investigated the wear status of the dies.

The results are shown in Table 2.

Here, the surface smoothness was evaluated by the presence or absence of aluminum sticking to the die after extrusion of a certain amount, and the wear of the die was evaluated by the presence or absence of a change in the shape of the die after extrusion of a certain amount.

Table 2 As can be seen from the comparison between Alloy No. 61 and Alloy No. 19.20, when the B content is less than 5%, seizure of aluminum to the die occurs, resulting in poor quality of the extruded material. In contrast, alloys Nos. 61 to 18 with a B content in the range of 5 to 10% can all have a good smooth surface, and alloys Nos. 20 and 20 have a good smooth surface. It can be seen that when B is contained in a large amount exceeding 10%, die wear becomes severe and extrusion characteristics deteriorate as a result. that's all

Claims (2)

[Claims] (1) An aluminum alloy for extrusion with excellent surface smoothness, containing B in a range of 0.5 to less than 10%, with the balance being aluminum and unavoidable impurities. (2) Contains B in a range of 0.5 to less than 10%, and further includes: Si: 0.05 to 13% Fe: 0.05 to 2% Cu: 0.05 to 7% Zn: 0.05 to 8% Mn: 2% or less Mg: 7% or less Cr: 1% or less Ti: 0.5% or less Zr: 0.5% or less Rare earth elements: 0.5 to 10% Pb: 1% or less Bi: 1% or less Contains one or more of the following: Ni: 0.05-6% V: 0.1-10% Co: 0.1-10%, with the balance consisting of Al and unavoidable impurities Excellent surface smoothness Aluminum alloy for extrusion.