JPS61117244A - Sliding aluminum alloy - Google Patents

Abstract

PURPOSE:To improve the wear resistance by adding small amounts of Sn, Zn and one or more among Si, Mn, Sb, Ti, Zr, Ni, Fe, W, Ce, Nb, V, Mo, Ba, Ca and Co to Al and carrying out dispersion precipitation. CONSTITUTION:The composition of a sliding Al alloy is composed of, by weight, 1-25% in total of <3% Sn (Snnot equal to 0%) and 0.5-3% Zn, <15% one or more kinds of elements selected out of a group A except Si, and the balance Al. The group A consists of Si, Mn, Sb, Ti, Zr, Ni, Fe, W, Ce, Nb, V, Mo, Ba, Ca and Co.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses aluminum (A1) as a base material. This invention relates to an aluminum-tin (Sn)-based sliding alloy. More specifically, the present invention provides an Al-Sn-based sliding alloy with improved wear resistance by dispersing a large amount of hard material in the Al--Sn-based sliding alloy.

Conventional aluminum-based sliding alloys, especially Al-Sn-based alloys, have been mainly used as bearing base metals. Under these conditions, direct contact between the shaft and the bearing is likely to occur, resulting in a large amount of wear on the bearing. Also, since it contains a considerable amount of Sn (approximately 20% by weight) and is relatively soft, the bearing cannot withstand the sudden explosive load from the piston and deforms, making it difficult to maintain good shaft-bearing clearance. Otherwise, a sufficient oil film may not be formed and smooth operation may not be achieved.

The present invention is based on an aluminum alloy that has excellent wear resistance and high load capacity, and is resistant to wear and deformation even when the shaft and bearing come into direct contact.
-In order to obtain a Sn-based alloy, a small amount of Sn is added to aluminum.
and Zn, Si, Mn, Sb, Tie
Zr, Ni, Fe, W, Ce, Nb, V,
It is characterized in that one or more additives selected from Group A consisting of Mo, Ba, Ca, and Co are added and dispersed and precipitated.

These dispersed precipitates are extremely hard, reaching several hundred Vickers hardnesses, and are considerably harder than the bearing's mating material, ie, the shaft, and these hard precipitates significantly improve the wear resistance of the bearing. Also, some of these additives are dissolved in solid solution.
l Improve the hardness of the base metal.

Coupled with the low Sn content, it has excellent load capacity.

The At-3n alloy of the present invention contains less than 3% S by weight percentage.
n (excluding 0%); 0.5 to less than a% Zn; total amount 1
~25% and the total amount excluding Si is 15% or less (Si, Mn, Sb, Ti, Zr, Ni,
Fe, W, Ca.

The alloy is based on an aluminum-tin alloy consisting essentially of one or more additives selected from Nb, V, No, Ba, Ca, and Co; and the remainder being A1.

By further adding one or more members selected from at least one of Group B, Group 0, and Group D to this alloy, an alloy with various characteristics can be obtained. Here, group B is Pb, Bi, T
Group 0 consists of Cu and Mg, and the total amount of one or more of them added is 9% or less; Group 0 consists of Cu and Mg, and the total amount added is 5% or less. Of course, when Group 0 is also added, it can be added arbitrarily within the range of its components, depending on the purpose and use, as in the case of Group B.

Group D consists of Cr, and the amount added is 0°1 for Group D alone.
~10%, 25% or less in total with group A, and Si
The total amount with the total amount of Group A excluding 15% or less.

Next, the characteristics of various elements added to this alloy will be shown.

Sn: Sn is an element added with the main purpose of reducing friction.
Adding 3% or more of this improves conformability and low friction, but it becomes difficult to disperse, reduces hardness, and tends to partially melt and cause fatigue failure during continuous high-load operation. ESN is an expensive metal, and from that point of view it is not desirable to add it in large amounts.The more finely ESN is dispersed in Al, the more it maintains overall mechanical strength while ensuring low friction. Both have a low Sn content and can be easily and finely dispersed, and the mechanical strength of the Al base is maintained.

If it is less than 0.1%, there is almost no effect of reducing friction by adding it, but it may be added. Preferably 0.5-3%
less than It is preferable to reduce the Sn content when particularly high load capacity is required, such as in a high-load wear-resistant material, and to increase the Sn content when low friction and conformability are required, such as in a bearing material. Low friction.

When more conformability is required, the content is more preferably less than 2 to 3%. In particular, if both functions such as load resistance and low friction are required, additional methods described below may be used to assist.

Zn: Since Zn is an element with a relatively high solid solubility limit in Al, most of it is dissolved in Al ground even within the scope of addition to the aluminum alloy according to the present invention. In general, binary alloys made of aluminum containing a small amount of zinc are not put into practical use due to their low strength. It is well known that alloys are used. The present invention differs from conventional zinc-containing aluminum alloys in that Al
The purpose of adding zinc is to improve the fatigue strength, load capacity, and high temperature hardness by strengthening the base. Although Zn is generally called a low melting point metal like Sn, it has a higher melting point than Sn and is poor in compatibility. However, when Zn is added to an aluminum-based alloy containing Sn, such as the aluminum-based alloy of the present invention, the above-mentioned properties are improved without impairing the conformability. Z below 0.5%
The effect of n is almost negligible, and when it is less than 3%, the load carrying capacity decreases. The combination with Group 6 and/or Group D, which will be described later, promotes the effect of Zn addition, making it extremely difficult for high-temperature hardness to decrease, and as a result, load capacity and fatigue strength are significantly improved.

Group A: Group A is Si, Mn, Sb, Ti, Zr, Ni
, Fa, W, Ca.

Consists of Nb, V, Mo, Ba, Ca, and Co. A crystallized product is produced by casting one or more of these elements (generally added in the master alloy) together with A1.

Produces precipitates, etc. These crystallized substances, precipitates, etc. are all hard substances with a Vickers hardness of several hundred or more, and thus improve the hardness and wear resistance of the entire alloy. It also has the effect of strengthening the Al base. Increasing amounts of this additive improve wear resistance, but if the total amount exceeds 15%, the alloy becomes too hard and brittle. However, if Si is selected as an additive and the precipitates are finely dispersed, the total amount of Group A excluding Si can be reduced to 2% within the range of not exceeding 15%.
It can be added up to 5%. When added in excess of 25%, wear resistance decreases and 1 bending strength decreases extremely.
Begins to significantly damage the other material.

When the total amount of Group A is less than 1%, sufficient wear resistance cannot be obtained because hardly any hard substances are precipitated.

If the precipitation form of the above-mentioned precipitates is such that it inhibits the growth of aluminum crystal grains at high temperatures during bearing manufacture and use, fine and uniform dispersion of Sn particles is promoted. In this regard, each element such as Si has a promoting effect to varying degrees, and this effect is particularly remarkable when the amount added is small. Note that an alloy obtained by alloying these additive elements with each other or an alloy obtained by alloying them with A1 may be added. Also, among the elements in group A, the preferred order of addition is first Si, then Mn, and then S.
b, then Zr, Mo, Fe, Co, then ri,
Nbt W+ V Finally Ni.

The order is Co, Ba, and Ca. The reason for this is that Si itself has excellent hardness and castability, so it is most preferable to select it.
The degree of uniform dispersion of intermetallic compounds with I or other elements and castability are taken into consideration. However, in that ranking, Mo
, Fe, and Co have somewhat poor corrosion resistance, so under usage conditions where corrosion resistance is particularly required, consideration must be given to reducing the amount of these added or using other elements.

From the above points, alloys in which one or more of Si, Mn, and Sb are selected have a particularly remarkable effect of adding Group A.

The forms of Group A precipitates (or crystallized substances, the same shall apply hereinafter) include precipitates consisting of these additive elements alone, precipitates consisting of intermetallic compounds of these additive elements, and intermetallic compounds between these additive elements and Al. There are precipitates made of compounds and precipitates made of intermetallic compounds of these additive elements and intermetallic compounds of Al, but any form of precipitates has an effect on wear resistance and the like.

These precipitates have a Vickers hardness of several hundred, and are extremely hard, so these precipitates can significantly reduce the wear of the bearing due to friction with the shaft. Dispersion produces positive effects.

The appropriate amount range is as described above, but more preferably S
When i is included, it is 1 to 15%. Also, in group A, Si
It is more preferable that the total amount excluding the above is 10% or less.

In a preferred range, the precipitates are more uniformly dispersed and have the effect of improving wear resistance without adversely affecting other performance.

Group B: Group B consists of Pb, Bi, Tl, and In. When one or more of these is added in a total amount of 9% or less, the properties of Sn as a metal having low friction properties can be particularly improved. In addition, these elements, such as p
When b is present together with Sn, it partially forms a Sn-Pb alloy, and when metal contact occurs due to the presence of an alloy with a lower melting point than Sn and Pb, a particularly low friction effect is exhibited. Ru. Of course, it goes without saying that even if it exists in an unalloyed form, it still has low friction properties.

The order of these additions is first Pb, In, then B.
The order of T1 as the last is preferred because Pb and In flow most easily when subjected to pressure, and therefore have excellent compatibility and conformability. pb is further Sn
It is much cheaper than other methods, and is more preferable because it can be stably supplied. The next Bi is slightly harder and has a slightly higher melting point than the above Pb and In, and the last T1 has the properties of Pb.
, is on the same level as In, but resources are scarce and expensive.

When the total amount of Group B exceeds 9% by weight, non-uniform dispersion occurs, the load capacity is significantly reduced, the hardness of the alloy as a whole is reduced, and the wear resistance is deteriorated.

It is preferably added in a range of 0.1 to 5%.

If the amount added is less than 0.1%, the effect of improving the properties of Sn as a metal, such as low friction properties, cannot be expected much, but it may be added. Furthermore, when wear resistance and load resistance are particularly required, addition of 3% or less is more preferable. This is because when improving the properties of Sn as a metal having low friction, etc., depending on the combination of elements in group A, the Al base may be considerably softened by adding a large amount of group B. Incidentally, the additive elements of group B also have the effect of improving the machinability of the alloy and facilitating post-processing when manufacturing bearing materials and the like.

Group 0: Group 0 consists of Cu-Mg. This element not only increases the hardness of the Al substrate, but also produces special effects when combined with other additive elements.

Cu forms an α solid solution with A1 and improves the mechanical properties such as increasing the bending strength of the alloy, as well as improving the wear resistance. If added in excess of 5%, the alloy becomes brittle. 0.5
% or less, it is not very effective, but it may be added.6 In particular, when wear resistance is required, 2 to 5% is more preferable. When emphasis is placed on improving mechanical properties, the content is more preferably 0.5% to less than 2%.

Like Cu, Mg can improve the hardness of the Al base and provide high load capacity. When added in excess of 5%, processability decreases. More preferably 3% or less. In addition, when the shaft is added at the same time as Cu, a part of it forms a ternary alloy of Al-Cu-Mg, and when a large amount of group A is added and precipitated, it also has the effect of more stably dispersing the precipitates in the A1 ground. be. In this case, the total amount of Cu and MH added is preferably 5% or less65
If added in excess of %, the improvement in mechanical properties will decline.

Group D: Group D consists of Cr. Cr has two special effects. Firstly, when it is added in an amount of 1% or more, it improves the hardness of the A1 substrate, and also improves the hardness of the A1 substrate due to the precipitation (or crystallization) of some of it. Abrasion resistance is also improved.

If the total amount added with A group containing Si exceeds 25%, wear resistance begins to decrease, and if the total amount added with A group excluding Si exceeds 15% or Cr alone exceeds 10%. and the alloy becomes too hard and brittle.

Next, at 0.1 to 1%, no significant improvement in wear resistance due to precipitates is observed, but due to the solid solution of Cr in the Al base and the fine dispersion of the precipitates, the effect of preventing the softening of the AI base at high temperatures is effective. Yes, it further improves load bearing capacity. Further, the alloy of the present invention is S
Since the n content is low, it can be easily refined, but
Due to the finely dispersed Cr mentioned above, at high temperatures (approximately 400℃
), coarsening of Sn is also prevented and fine Sn grains can be maintained. In this way, Sn does not move or become coarse at high temperatures, and the fatigue resistance is improved. Furthermore, Cr
When Cu and/or Mg of the above six groups are used in combination with
and/or Mg further improves the high temperature hardness of the ^1 alloy and further improves fatigue resistance. The effect of Cr cannot be expected much if it is less than 0.1. A more preferable range is 0.
It is 1 to 6%.

In this way, the aluminum-based sliding alloy of the present invention has a low Sn
and Zn, and has precipitates of additives selected from Group A, so it has extremely excellent wear resistance. Furthermore,
The present invention provides various alloys by adding all combinations of Groups B to D, and although there are slight differences, all of them have excellent wear resistance.

Furthermore, it has various characteristics such as conformability, low friction, fatigue resistance, and high load capacity. In other words, this alloy group can be used in sliding parts that require wear resistance, and by changing the type and amount of additives depending on the sliding conditions, it can easily meet that requirement. .

The aluminum-based sliding alloy of the present invention can be used as a bearing material, which is a type of sliding material, by press-welding a backing steel plate. Of course, the six alloys of the present invention may also be used as sliding members.All of the six alloys of the present invention have excellent wear resistance and high load capacity, and can withstand use under harsh conditions of high speed and high load.

In addition, the compatibility is determined by Sn or B group Pb, Bi,
Although Tl and In can be improved considerably, the high load capacity is slightly reduced, so when both high load capacity and conformability are especially required, alloys with a combination of particularly high load capacity,
For example, if Si is selected as Group A, Cu-Mg is selected as Group 6, and Cr is selected as Group D, and an overlay of a PB alloy is formed on this alloy, the load capacity will be almost the same as that of the alloy selected from the present invention. First, the conformability and seizure resistance are almost the same as those of the overlay PB alloy, making it a very good composite sliding material. At this time, the overlay thickness is 1 μm
Below this, there is little effect on seizure resistance and conformability, and the overlay is likely to peel off due to fatigue. On the other hand, it becomes too thick (several hundred microns)
In case m), the load resistance is reduced due to the soft Pd-based alloy, so the thickness is preferably 1 to 150 μm. The overlay alloy is not limited to Pd-based alloys, but also has improved low friction properties.
Any material may be used as long as it improves seizure properties, but it is desirable that the thickness be adjusted so as not to lose the high load capacity and wear resistance of the alloy of the present invention, and to prevent fatigue peeling. Further, the overlay may be formed in two or more layers as necessary.

Next, the present invention will be explained by examples. Table 1 below shows the compositions of alloys (samples) 1 to 30 according to the present invention and comparative alloys (samples) 31 to 34.

(Left below) Samples 1 to 34 in Table 1 were prepared by melting A1 base metal in a gas furnace and then melting Al-5i master alloy, Al-Mn master alloy, Al-
Ti master alloy, Al-Zr master alloy, Al-Ni master alloy, A
l-Fe master alloy, Al-W master alloy, Al-Ce master alloy,
Al-Nb master alloy, Al-V master alloy, Al-No master alloy, Al-Ba master alloy, Al-(:, a master alloy, Al-C
o Master alloy, Al-Cu master alloy, Al-Mg master alloy, Al
-Cr master alloy is melted according to the target components, and finally Sn,
Zn, Sb, Pb, Bi, T1. After adding In according to the target components, degassing treatment was performed, and casting was performed in a mold (thickness 18 m + i), followed by rolling and annealing (350 ° C. for 4 hours) into 2 pieces or 1 mm each. Samples (alloy thickness 2 mm) were prepared repeatedly and the following tests were conducted.

It goes without saying that the alloy composition according to the present invention contains impurities that cannot be avoided by ordinary refining techniques.

Table 2 below shows the results of the wear resistance test, and the test was conducted as follows.6 First, while pressing a test material block (alloy ingot) against a rotating steel ring with a constant load, the rotating ring was rotated. Rotated and slid. After carrying out a specific sliding time test, the shape change of the block was measured, the volumetric wear amount (mm3) was measured, and the wear resistance was determined. The test conditions were a load of 2,000 g, a circumferential speed of 800 am/min, and no lubrication.

Table 2 As is clear from Table 2, all alloys 1 to 30 according to the present invention have a significantly reduced amount of wear compared to comparative alloys 31 to 34, and have improved wear resistance. I understand that.

Furthermore, when the amount of Group A added is high, the wear resistance also tends to be high. Although only the wear resistance is shown here, the load capacity also shows a similar tendency.

Table 3 shows the results of the abrasion resistance test in the same way as Table 2, but
Oil drip was added as a condition. SAE 10W30 engine oil was used as the lubricating oil, and one drip was set at 10 l/min. Other conditions were the same as the above-mentioned test conditions without lubrication except for lubrication.

Table 3 In Table 3, only some of the alloys of the present invention are shown, but
All have higher wear resistance than Comparative Alloys 31-34.

As described above, under the lubrication conditions, the effects of the amounts of other groups added are rather more dominant than the amounts of group A added.

As described above, the alloy of the present invention has particularly excellent wear resistance.

Claims (16)

[Claims] (1) Sn less than 3% by weight percentage (excluding 0%); 0
．． 5 to less than 3% Zn; one or more additives selected from Group A having a total amount of 1 to 25% and a total amount excluding Si of 15% or less; and the remainder substantially consisting of aluminum. An aluminum-based sliding alloy. Group A: Si, Mn, Sb, Ti, Zr, Ni, Fe, W
, Ce, Nb, V, Mo, Ba, Ca, Co (2) The aluminum-based sliding alloy according to claim 1, wherein Si is selected from Group A. (3) The aluminum-based sliding alloy according to claim 1, wherein Mn is selected from Group A. (4) The aluminum-based sliding alloy according to claim 1, wherein Sb is selected from Group A. (5) The aluminum-based sliding alloy according to claim 1, wherein Si and Mn are selected from Group A. (6) The aluminum-based sliding alloy according to claim 1, wherein Si and Sb are selected from Group A. (7) The aluminum-based sliding alloy according to claim 1, wherein Mn and Sb are selected from Group A. (8) The aluminum-based sliding alloy according to claim 1, wherein Si, Mn, and Sb are selected from Group A. (9) Sn of 3% or less by weight percentage (excluding 0%); 0
．． 5-8% Zn; one or two selected from Group A with a total amount of 1-25% and a total amount excluding Si of 15% or less
An aluminum-based sliding alloy consisting of at least one additive; one or more additives selected from at least one of Group B, Group C, and Group D; and the remainder substantially consisting of aluminum. Group A: Si, Mn, Sb, Ti, Zr, Ni, Fe, W
, Ce, Nb, V, Mo, Ba, Ca, Co Group B: Pb, Bi, Tl, In, Group B is 9% or less in total Group C: Cu and/or Mg is 5% or less Group D: 0. 1 to 10% Cr (However, the total amount added with group A is 25% or less, and the total amount added with group A excluding Si is 15% or less) (10) The aluminum-based sliding alloy according to claim 9, wherein Si is selected from Group A. (11) The aluminum-based sliding alloy according to claim 9, wherein Mn is selected from Group A. (12) The aluminum-based sliding alloy according to claim 9, wherein Sb is selected from Group A. (13) The aluminum-based sliding alloy according to claim 9, wherein Si and Mn are selected from Group A. (14) The aluminum-based sliding alloy according to claim 9, wherein Si and Sb are selected from Group A. (15) The aluminum-based sliding alloy according to claim 9, wherein Mn and Sb are selected from Group A. (16) The aluminum-based sliding alloy according to claim 9, wherein Si, Mn, and Sb are selected from Group A.