JPS62222039A - Aluminum alloy excellent in wear resistance and extrudability - Google Patents

Abstract

PURPOSE:To obtain an Al alloy excellent in wear resistance and extrudability and reduced in cutting-tool wear and falling of hard grains at the time of machining, by specifying a composition consisting of Mg, Si, Mn, and Al. CONSTITUTION:The Al alloy has a composition consisting of, by weight, 1.9-7.6% Mg, 1.6-4.9% Si, 0.5-1.5% Mn, and the balance Al with inevitable impurities and further containing, if necessary, either or both of one or more kinds among 0.3-1.0% Fe, 0.03-0.25% Cr, 0.05-0.25% Zr, and 0.03-0.25% V and 0.05-0.5% Cu and/or 0.25-1.5% Zn. This Al alloy is excellent in wear resistance and extrudability and reduced in cutting-tool wear. It is preferable that the above Al alloy is subjected to homogenizing treatment at about 400-575 deg.C after casting. Moreover, it is desirable that extruding of the above Al alloy is carried out at about 350-550 deg.C at >=about 75% extruding draft.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an aluminum alloy with excellent wear resistance and extrudability.

[Conventional technology]

In general, aluminum has low hardness and poor wear resistance, so various alloying components are added to aluminum to increase its hardness and improve its wear resistance1.For example, JIS-H4140C regulations In the case of 4032 aluminum alloy, it is 110 to 13. A large amount of Si? Addition of hard Si into aluminum
4' Distribute the children.

It has rich wear resistance.

[Problem that the invention seeks to solve]

However, the above-mentioned high Si content aluminum alloy
Although it has excellent wear resistance, it has poor extrudability, so
Particularly, pipes, etc., are mounted by porthole extrusion using turning tools, and since the hardness of Si particles is extremely high, when cutting such aluminum alloys, wear of the cutting tool is a problem. In addition, these Si particles fall off on the finished surface, reducing the roughness of the cut surface, generally resulting in poor machinability, and a large amount of S dispersed in 1M.
Unfortunately, the i-particles also impair corrosion resistance.

[Based on research (findings)]

The inventors of the present invention have conducted various studies in view of the above-mentioned circumstances.

(1) The Si content in the high Si-containing M alloy is 1.
Reduce the Mg content to 6-4.9% by weight and reduce it to 1.9-4.9% by weight.
When the Si content is increased to 7.6% by weight, the extrudability and corrosion resistance of the M alloy are improved due to the decrease in Si content.

Most of the Si forms an intermetallic compound called iVIg 2 Si, and this Mg 2 Si is bidispersed in M to prevent the decline in wear resistance associated with the decrease in Si content. 2) When 0.5 to 1.5% by weight of Mn is contained in the M alloy containing Si and Mg as described above, this Mn, including Fe (described later), becomes M - (Mn, Fe).
-3i-based gold metal compound (α phase) is formed, and this α phase is dispersed in M to improve the wear resistance of M@gold. In other words, in combination with what was stated in (1) above.

By reducing the amount of Si particles dispersed in the high Si-containing M alloy, the extrudability and corrosion resistance of this M alloy are improved, while by increasing the amount of Mg and adding Mn therein, Mg2Si and M-(Mn.

Fe)-8i-based compounds are formed, and these intermetallic compounds are dispersed in M to compensate for the decrease in wear resistance that would occur due to the reduction of Si particles. It maintains abrasion resistance comparable to that of P, 6@g containing a target height of 81, and also has excellent extrudability.

(3) In the M alloy containing the above amounts of Si and Mnk, further Fc: 0.3 to 1.0%, Cr
:0.03~025%, Zr:0.05~0.25%
and V: 0.03-0.25% (% is total weight%,
When one or more of the following are also added (=% means weight % unless otherwise specified), these components combine with 1Al and Si in the same manner as the above Mn to form the AA. - (Mn, Fe) Si-based intermetallic compounds 2 are formed and these compounds are dispersed in M to further improve the wear resistance of the M alloy.

(4) M alloy containing the above amounts of Si, Mg and Mn, or further containing the above amounts of Fe, Cr, Z
fc containing one or two of r and V
For M alloy.

Cu: 0.05-0.5% and Zn: 0.25-1.
The addition of one or two of these M
To increase the strength of the alloy.

I found out.

[Means for solving problems]

This invention was invented based on the above knowledge, and aims to provide an aluminum alloy that has excellent wear resistance and extrudability, and is less likely to wear out the cutting tool or shed hard particles during cutting.

Mg: 1.9-7.6%.

Si: 1.6-4.9%, Mn: 0.5-1.5%.

and, if necessary, Fe: 0.3-1.0%.

Cr: 0.03~0.25%1 Zr: 0.05-0.25%.

V: 0.03-0.25%.

one or more of the following, and Cu: 0.05-0.5%.

Zn: 0.25 to 1.5%, containing one or two of the following, and the remainder being Al and inevitable impurities. Aluminum alloy with excellent wear resistance and extrudability.

This is related to.

Next, the reason for limiting the component composition range as described above in this invention will be described.

(1) Mg The Mg component has the effect of increasing the strength of the M alloy by solid solution in 1M, thereby increasing the deformation resistance during extrusion of the M alloy, but by coexisting with Si, most of the Mg component is dissolved in Mg.
Since it forms an intermetallic compound called 2Ss, this tVIg2Si contributes to improving the wear resistance of the M alloy without impairing its extrudability. Since the amount of Mg is 1.9 to 7.6%, when combined with the Si content (1.6 to 4.9%, which will be described later), the amount of Mg2Si is 3 to 12%. 2S
It will be included in a form other than i. This 'Wig 2
If the S J content is less than 3%, sufficient wear resistance cannot be obtained, while if it exceeds 12%, Mg 2 Si crystallizes in the form of primary crystals, which deteriorates the extrudability of the M alloy. Since it impairs machinability, the Mg content is
Si content: 1.9-7 above corresponding to 3-12%
．． It was set at 6%.

(2) 5i Si532 is combined with Mg to form Mg2S as described above.
The Mg 281 particles form an intermetallic compound called i, and these Mg 281 particles impart wear resistance to the M alloy and do not impair the corrosion resistance of the M alloy like free Si particles. After forming, the remaining Si component is M, Mn, 6, or Fe + as described below.
Combined with any one or more of Cr + Zr + 1, for example, A-e (Mn, Fe) S
An i-based intermetallic compound (α phase) is formed, and this α phase is also dispersed in M to improve the wear resistance of the alloy.

Therefore, in this invention, the Si content is set to 1,6 It was set at ~4.9%.

(31Mn Mn is a component that combines with 1Al and Si as described above and helps form the α phase that contributes to improving wear resistance, but if its content is less than 0.5%, wear resistance If it exceeds 1.5%, it will form a huge primary crystal compound and have a negative effect on the machinability and elongation of the M alloy, so the content should be reduced to 0.5%. It was set at ~1.5%.

(4) Fc, Cr, Zr and VFe,
Like Mn, Cr, Zr, and V components all combine with taU and St to form intermetallic compounds.

This has the effect of further improving the wear resistance of A4 alloy, so it is necessary (: added as required, but the content is 0.3%, 0.03%, 0.05%, and 0.03%, respectively).
If it is less than 1.0% pcrrZr for Fe, the effect of further improving the wear resistance cannot be obtained;
If V exceeds 0.25%, giant primary crystal compounds are formed and the machinability and elongation of the alloy deteriorate. .0%, 0.0% for Cr and ■.
03-0.25%, and 0.05-0 for Zr
．． It was set at 25%.

(5) Cu and Zn Cu and Zn components are dissolved in 1 MM = solid solution and have the effect of increasing its strength, so they are contained in the alloy of this invention as necessary, but if their content is 0 in Cu If it is less than 0.05% for Zr, and less than 0.25% for Zr, sufficient effects will not be obtained for the above-mentioned effects, while on the other hand, if it exceeds 0.5% for Cu, the corrosion resistance of the M alloy will be impaired.

However, if Zn exceeds 1.5%, the surface finish of the M alloy will deteriorate during cutting, so the content of these components should be adjusted to 0.05 to 0.5% for Cu.
%, and Zn was set at 0.25 to 1.5%.

In addition, in the M alloy of this invention, after casting it,
Homogenization of casting structure, solid solution of Mg, Si components, etc.

Spheroidization of Mg2Si compounds and M (Mn, F
e) In order to promote the fine precipitation of -8i-based compounds and reliably impart the desired wear resistance, extrudability and strong deformation to this M alloy, it is necessary to perform homogenization treatment, and this homogenization If the treatment temperature is less than 400°C, the above effect cannot be sufficiently obtained, while if it exceeds 575°C, there is a risk of partial eutectic melting.
Must be ~575°C.

Furthermore, when the M alloy of the present invention is processed into various parts by extrusion, if the extrusion process is carried out at a temperature other than 350 to 550°C, surface cracks will occur during extrusion.
If the deformation during extrusion is less than 75%, cavities in the ingot,
Due to insufficient coverage of casting defects such as pinholes, these defects remain after extrusion, deteriorating the mechanical properties of the product and the surface quality after cutting.
This extrusion process must be carried out at a temperature of 350 DEG to 550 DEG C. and an extrusion change of greater than 75%.

〔Example〕

Next, the present invention will be explained by way of examples while comparing with comparative examples.

The present invention M8 each having the component composition shown in Table 1.
- Fri 1-13. Comparative M alloys 1 to 8 having compositions outside the scope of this invention (deviating components are indicated by * in Table 1)
, and from the molten metal of the conventional M alloy corresponding to the high Si-containing M alloy of JIS 4032, both diameter = 200
After casting the WrIrI billets, these billets were subjected to a homogenization treatment at 56 o C for 6 hours. The billet was then extruded into a round bar with a diameter of 36 mm at a wet temperature of 500°C. Next, after tensile straightening these round bars, they were kept at a temperature of 530°C for 1 hour for solution treatment, then water quenched, and then heated to a temperature of 530°C.
was subjected to T6 treatment for 8 hours.

During the above extrusion, the maximum extrusion length at which a round bar could be extruded without causing cracks on the surface of the extruded product was measured, and the extrudability of each of the alloys was evaluated based on this.

In addition, the above-mentioned present invention first alloy, comparative taU alloy and conventional M
In order to evaluate the wear resistance of the alloys, cylindrical pins having a diameter of 4 mm at the contact surface were cut out as test pieces from each of the above-mentioned round bars made of these alloys, and these pins were divided into pin disks. Using a type of wear tester, contact pressure crab 3ooy/-1 friction speed M: l 250 m
The amount of wear on each pin was measured by pressing it against a rotating FC25 cast iron disk for 100 minutes under the conditions of /mix.

Furthermore, we observed the tool wear of the above-mentioned M Goe compared to the conventional JIS 4032 Go Haku.

Each tool is marked with an X if it has experienced significant wear similar to that of this JIS 4032 alloy and is no longer able to maintain the normal surface roughness IW. The evaluation was made with the mark Δ, and the case with almost no wear was evaluated with the mark O.

These results are also shown in the first column.

〔Effect of the invention〕

From the results shown in Table 1, the M alloys 1 to 13 of the present invention all have a high maximum extrusion speed, have a small amount of wear, and have little tool wear.

Comparative AJ@ml has too little Mg and St, so the amount of wear is large, and Comparative M alloy 2 has too little Mg even though Si is present, so the wear resistance is still poor.

Comparative Ae alignment 3 has too many storms, resulting in poor extrudability and significant bite wear. Comparative M alloy 4 has too little St content, resulting in a large amount of wear, and the ratio is $! 2AJ alloy 5 is 5
Too much itJ causes severe tool wear.

Comparative M alloy 6 has too much Mg and Si, resulting in extremely poor extrudability and severe bite wear; comparative M alloy 7 has low wear resistance due to a lack of Mn; and comparative M alloy 8 has low wear resistance. It can be seen that tool wear is severe due to too much Mn.

As is clear from the above description, the present invention provides not only superior extrudability but also superior wear resistance, comparable to or better than conventional high Si-containing layer alloys; It is possible to provide an M alloy suitable as a material for sliding parts such as pneumatic cylinders and hydraulic cylinders that particularly require such properties.

Claims (4)

[Claims] (1) A component containing Mg: 1.9 to 7.6%, Si: 1.6 to 4.9%, Mn: 0.5 to 1.5%, and the remainder consisting of Al and inevitable impurities. characterized by having a composition (more than % by weight),
Aluminum alloy with excellent wear resistance and extrudability. (2) Contains Mg: 1.9 to 7.6%, Si: 1.6 to 4.9%, Mn: 0.5 to 1.5%, and further Fe: 0.3 to 1.0 %, Cr: 0.03-0.25%, Zr: 0.05-0.25%, V: 0.03-0.25%, and the remainder is A
Component composition consisting of l and unavoidable impurities (weight%)
An aluminum alloy with excellent wear resistance and extrudability. (3) Contains Mg: 1.9 to 7.6%, Si: 1.6 to 4.9%, Mn: 0.5 to 1.5%, and further Cu: 0.05 to 0.5. %, Zn: 0.25 to 1.5%, and the remainder is Al and inevitable impurities (weight %). Aluminum alloy with excellent wear resistance and extrudability. (4) Contains Mg: 1.9 to 7.6%, Si: 1.6 to 4.9%, Mn: 0.5 to 1.5%, and further Fe: 0.3 to 1.0 %, Cr: 0.03-0.25%, Zr: 0.05-0.25%, V: 0.03-0.25%, one or more of the following, and Cu: 0. Zn: 0.25 to 0.5%, Zn: 0.25 to 1.5%, and one or two of the following, and the remainder is Al and inevitable impurities (weight %). An aluminum alloy with excellent wear resistance and extrudability.