JPH01294840A - Wear-resistant aluminum alloy - Google Patents

Abstract

PURPOSE:To facilitate the manufacture of sliding parts by specifying respective contents of Si, Fe, Mn, P, Na, Sr and Sb in an Al alloy and also forming a coarse eutectic Si structure so as to improve wear resistance and castability. CONSTITUTION:Additive elements in a wear-resistant Al alloy are constituted so that Si, Fe, Mn, P, Na Sr and Sb contents are controlled to 9-13% by weight, <0.3%, <0.3%, <0.001%, <0.002%, <0.03% and <0.04%, respectively, and, if necessary, 0.3-0.6% Mg is added. At the time of casting this Al alloy into the prescribed parts shape, the structure of this Al alloy is formed into a coarse eutectic Si structure, e.g., by controlling the cooling rate to about 0.1-1 deg.C/sec. Since this Al alloy has superior castability, sliding parts, etc., can be easily manufactured. Further, this Al alloy has excellent wear resistance, by which the seizure load of sliding parts, etc., is increased and wear loss can be reduced.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Field of Application) The present invention relates to a wear-resistant aluminum alloy particularly suitable for use as a material for sliding parts in parts for various mechanical structures such as automobile parts and industrial machine parts. (Prior art) Conventionally, for example, cast iron has often been used as a material for sliding parts, but since such steel-based materials have a high specific gravity, they have the disadvantage of increasing weight. There is. On the other hand, the specific gravity of sliding parts made of aluminum-based materials is considerably lower than that of steel-based materials, which often contributes to weight reduction, and the use of aluminum alloys as a material for sliding parts is also expanding. ing. Conventionally, aluminum alloy castings include Al-Cu-5.
i-based alloy (e.g. Al-4%Cu-5%Si, JIS
AC2A, AC2B; Rautal), AfL-5i
system alloy (e.g. Al-12%Si eutectic alloy, JIS
AC3A, Sirumin), AM-3i-Mg alloys (e.g., JIS AC4A, AC4C'; γ Sirumin), AJI-Si-Cu alloys (e.g., JIS
AC4B; copper-containing silmine), An-Si-Cu-Mg
alloys (e.g. Al-5%5t-1, 3%Cu-0,
5%Mg, JIS AC4D), AlAl1-3t
-Cu-Ni-based alloy (e.g. Al-12%5t-1
%Cu-2%Ni-1%Mg, JIS AC8A, A
C8B: Low-X or AC8 with Ni removed from this
C) are known, and in particular, wear-resistant aluminum alloys used as materials for sliding parts include hypereutectic Al
-3i-based Fe, Mn, Ni. It is a eutectic Al-5i alloy containing Mg, etc., and by increasing the cooling rate, fine S
(kl-3, in which a eutectic microstructure is obtained by adding a third element and selecting solidification conditions)
Examples of i-based alloys include those disclosed in JP-A-57-108239. ) etc. (Problem to be Solved by the Invention) However, among the abrasive aluminum alloys used as materials for conventional sliding parts as described above, the former AJI-5t alloy has a high resistance to wear. It is difficult to control the size and distribution of primary Si, which affects wearability, and the life of melting furnaces and casting molds is shortened due to high melting and competitive casting temperatures. Due to the addition of crystalline Al-5t elements, a large amount of sludge is generated, which can have a negative impact on the melting furnace and the product.Also, the cooling rate must be increased to make the Si finer, so large casting products are not suitable. The problem was that it was difficult to manufacture. (Objective of the Invention) The present invention was made in view of the above-mentioned problems in the prior art. It is possible to reduce the amount of wear on parts, and the conventional hypereutectic An-
Unlike Si-based alloys, the distribution of primary Si is not a problem, and the eutectic An-5i alloy has lower melting and casting temperatures than hypereutectic AJI-Si alloys, making it easier to melt. It is possible to prevent the lifespan of the furnace and casting molds from being shortened, and since it does not contain elements that tend to generate sludge, such as Fe and Mn, it is possible to prevent the adverse effects of sludge on the melting furnace and products. Aims to provide #wearable aluminum alloy.

[Structure of invention! f, ] (Means for solving the problem) The wear-resistant aluminum alloy according to the present invention has Si of 9
~13% by weight, less than 0.3% Fe, less than 0.3% Mn, and o. ooIB less than 1%, Na less than 0.002% by weight, Sr less than 0.03% by weight, S
b is regulated to less than 0.04% by weight, and Mg is reduced to 0 if necessary.
It is an aluminum alloy containing 3 to 0.6% by weight, and is characterized by having a coarse eutectic Si structure. It is characterized by being a means to solve the conventional problems. The reason why the composition (weight %) of the #wearable aluminum alloy according to the present invention is limited as described above will be explained. First, Si is an effective element for achieving wear resistance. The melting point (liquidus temperature) is the lowest at approximately 577°C with a eutectic composition (Si content of approximately 12.7%), but even if the Si content is lower than this, it is still higher than this. However, the melting point increases and the melting and casting temperatures become higher.
Since the life of the melting furnace, casting mold, etc. is reduced, the Si content is set in the range of 9 to 13%. Next, although Fe has the effect of preventing seizure on the mold, it is an impurity element and forms intermetallic compounds such as FeAl3, A-Fe-3i, etc., resulting in a decrease in toughness and corrosion resistance. By adding it to alloys with high Fe content and improving strength, harmful Al-Fe-
Suppresses the crystallization of 3i intermetallic compounds. However, if the content of these elements is too high, sludge is likely to be generated.
Fe is harmful to the melting furnace and products, and can clog the stalk of the casting equipment. Mn was regulated to less than 0.3%. In addition, since P, Na, Sr, and Sb are effective elements for refining primary crystals and eutectic Si, P is less than 0.001%.
Na content is less than 0.002%. Sr was regulated to less than 0.03%, and Sb was regulated to less than 0.04%. In addition, since Mg is an effective element for obtaining precipitation hardening of Mg2Si by heat treatment, Mg may be added as necessary in the range of 0.3 to 0.6%. Additionally, in order to improve heat treatability and improve strength, Cu may be added in an amount of 2 to 5% as needed, and Ni may be added in an amount of 0.1 to 1% to improve heat resistance. .5
It may be added as necessary within a range of %. The wear-resistant aluminum alloy according to the present invention has the above composition and has a coarse eutectic Si structure, thereby improving wear resistance. Such a coarse eutectic Si structure requires a cooling rate of 0.1~! when casting an aluminum alloy with the above composition into a predetermined part shape. In this case, if the cooling rate is slower than 0.1°C, it takes time to solidify after casting, which reduces productivity, so it is preferable. and the cooling rate is 1'Q/
If it is faster than S e G, the eutectic Si becomes finer and the wear resistance deteriorates, which is not preferable. After casting, the edges of the coarse eutectic Si structure can be rounded by performing heat treatment at 450 to 520°C for about 0.5 to 8 hours, thereby further improving the strength. The heat treatment conditions in this case, which are desirable depending on necessity, will vary depending on the alloy components, but if it is low temperature, it will take time to melt, and if it is high temperature, it may partially melt, so 450 to 520 ° C. It is desirable to select a temperature within a certain range, and the solution time also varies depending on the alloy components, but if it is shorter than 0.5 hours, the solution will not be sufficient and the edges of the coarse eutectic Si will not be rounded. Therefore, solution treatment for more than 8 hours is not economical because it does not affect the strength. (Function of the invention) In the A-3i alloy, its wear resistance is greatly influenced by the size and distribution of Si particles, and in the hypoeutectic alloy,
The larger the size of the eutectic Si particles, the better the wear resistance. The aluminum alloy according to the present invention is a eutectic Al-5i alloy, which has a low liquidus temperature, and contains P, Na, Sr, Sb, etc., which are effective in refining eutectic Si. No third element was added, and the cooling rate during casting was set to 0.
By controlling it to 1-1"o/SeC, a coarse eutectic Si (about 100 lumen in length) structure can be obtained, which can provide wear resistance. , if necessary, heat treatment held at 450 to 520°C for about 0.5 to 8 hours, such as T6 treatment (solution treatment:
If the edges of the eutectic Si structure are rounded by applying artificial aging (510±5°C x 2 hours 1: 170±5°C x 5 hours), the strength will further increase. (Example) In practice 1, the Si content shown in Table 1 and the Fe amount of less than 0.3%,
Mn amount less than 0.3%, Pg less than o, ooi%, Na
amount less than 0.002%, Sr amount less than 0.03%, Sb
After casting using an An-5i alloy with a Si content of less than 0.04% and cooling at the cooling rate shown in Table 1, a part of the alloy with a Si content of 13% and a part with an Si content of 11% and 9%, T6 treatment (solution treatment: 510°C) was performed as heat treatment as shown in Table 1.
× 2 hours 9 Artificial aging: 170°C × 5 hours) to prepare a test piece (Example No. 1.2.3 of the present invention), and although the Si content was 13%, the other part was cast. Test piece (symbol F in Table 1)
Example No. 4) of the present invention was obtained. Next, the tensile strength of each test piece was measured, and the results were also shown in Table 1. In addition, a wear test was conducted using a pin-disk type wear tester to measure the seizure load and amount of wear. Among these, the measurement of seizure load is based on friction speed: 5 m
/sec, temperature: 80°C. Lubrication: oil, measurement of wear amount: friction speed: 3 m/s
ee, surface pressure: 50Kgf/cm2. Temperature: 80° C., with two lubricating oils, and measurements were taken from test pieces after 1100K friction. Note that spheroidal graphite cast iron with hard Cr plating was used as the mating material. The results are also shown in Table 1. Furthermore, when the metal structure of Inventive Example Alloy No. 2 was investigated, it was found that it had a coarse eutectic Si structure, as shown in FIG. It was recognized that it was round. Hypereutectic A1-3t alloy (A3
90 equivalent alloy) without controlling the cooling rate, and then subjected to the heat treatment shown in Table 1 to prepare test pieces. Next, the tensile strength of the above test piece was measured, and the results were also shown in Table 1. In addition, the seizure load and the amount of wear were measured using a bottle-disc type wear tester in the same manner as in the above examples. The results are shown in Table 1. Comparative Example 2 Casting using a eutectic An-51 alloy with the Si content shown in Table 1 and 0.005% Nai as the eutectic Si refinement element, and cooling at the cooling rate also shown in Table 1. After that, the same heat treatment shown in Table 1 was performed to prepare a test piece. Next, the tensile strength of the above test piece was measured, and the results were also shown in Table 1. In addition, the baking load and the amount of wear were measured using a pin-disc type wear tester in the same manner as in the above examples. The results are also shown in Table 1. As shown in Table 1, the invention example alloy No. 1~
Comparative Example Alloy No. 4 had approximately the same seizure load and wear amount as Comparative Example Alloy No. 1 (alloy equivalent to A390), and was recognized to have excellent wear resistance. and 1
Inventive example alloy Nos. 1 to 4, the liquidus temperature was 5.
Compared to Comparative Example Alloy No. 1, which had a temperature higher than 0°C, the life of the melting furnace, casting mold, etc. could be considerably improved. In addition, the Si content of Inventive Example Alloy No. 3 is 9%.
The alloy N according to the present invention has a Si content of 13%.
The seizure load is lower and the amount of wear is higher due to the lower Si content compared to O, I, and 4, but the seizure load is still considerably lower than Comparative Example Alloys No. and 2, which have finer eutectic Si. It is large and the amount of wear is quite small. In addition, in the alloy Nos. 1 to 4 according to the present invention, the content of Fe, Mn, etc., which tend to generate sludge, was regulated.
Sludge is less likely to be generated, and the melting furnace is not damaged and the product is not adversely affected. Furthermore, the present invention example alloy No. 024 which is as cast without heat treatment (symbol F) has the same Si content and the present invention example alloy No. which has been subjected to T6 treatment as heat treatment.
Compared to No. 1, the seizure load and wear amount were about the same, but the tensile strength was found to be slightly lower because the edges of the eutectic S+ were angular. Next, the present invention example alloy No. 081 and the comparative example alloy No.
Milling was performed on No. 1 and the amount of chip wear during plying was examined. The milling conditions are: cutting speed: 1200 m/min, depth of cut: 0.5 mm
It was carried out dry using a DC tool. This result is the second
As shown in the figure. As shown in FIG. 2, it was observed that the machinability of Inventive Example Alloy No. 1 was considerably improved compared to Comparative Example Alloy No. 11. [Effects of the Invention] The wear-resistant aluminum alloy according to the present invention is as follows. Contains 9 to 13% by weight of Si, less than 0.3% by weight of Fe, less than 0.3% by weight of Mn, less than 0.001% by weight of P, less than 0.002% by weight of Na, and 0.0% of Sr. 03% by weight
It is an aluminum alloy containing 0.3 to 0.6% by weight of Mg, with Sb being regulated to less than 0.04% by weight, if necessary, and having a coarse eutectic Si structure. , has extremely good castability, for example, makes it easy to manufacture sliding parts, etc., and has good wear resistance, so that, for example, the seizing load of sliding parts, etc. can be increased and the amount of wear is small. The distribution of primary Si crystals is not a problem as in conventional hypereutectic An-3i alloys, and the melting bone casting temperature is lower than that of hypereutectic An-3i alloys. Because it uses a lower eutectic A-3t alloy, it can extend the life of melting furnaces and casting molds, and it also does not contain elements that tend to generate sludge, such as Fe and Mn. Because there is no sludge, it is possible to prevent the generation of sludge from having a negative impact on the melting furnace and products, etc., and it is possible to provide sliding parts with particularly excellent wear resistance at a low price with good productivity. This brings about a significant effect.

[Brief explanation of the drawing]

Figure 1 is a metallographic micrograph (50x) showing the solidified metallographic structure of the example alloy (No. 2) of the present invention;
The figure is a graph illustrating the results of measuring the amount of chip wear during milling. Patent applicant Nissan Motor Co., Ltd.

Claims (1)

[Claims] (1) Contains 9 to 13% by weight of Si, less than 0.3% by weight of Fe, less than 0.3% by weight of Mn, less than 0.001% of P, less than 0.002% of Na, Sr 0.03
% by weight, Sb is regulated to less than 0.04% by weight, and if necessary contains Mg from 0.3 to 0.6% by weight, and has a coarse eutectic Si structure. Features wear-resistant aluminum alloy.