JPS6140026B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aluminum-tin (Sn) bearing material having aluminum (Al) as a base material. More specifically, the present invention provides an Al--Sn-based bearing alloy with excellent wear resistance, which is obtained by improving the low-melting point material contained in the Al--Sn-based bearing alloy and dispersing a large amount of hard substances in the alloy. There is a particular thing. Al-Sn bearing alloys are mainly used as conventional aluminum bearing alloys, but these alloys are used in modern automobile internal combustion engines under higher speed and higher load conditions. The intervening lubricating oil film becomes thinner, making direct contact between the shaft and the bearing more likely to occur, which may result in increased bearing wear or seizure. Therefore, the object of the present invention is to provide an Al--Sn bearing alloy that has sufficient wear resistance even when the shaft and bearing come into direct contact, and also has excellent load carrying capacity. That is, Sn3 to 40 with Al as the substantial remainder.
%, lead (Pb) 0.1-9.0%, antimony (Sb) 3.0
% to 10.0%, and 0.1 to 3.0% of copper (Cu) and/or magnesium (Mg), and hard substances precipitated in the base material are dispersed in the base material by rolling. Straight bearing alloy (alloy 1). Alloy 1 contains silicon (Si), nickel (Ni), manganese (Mn), titanium (Ti), iron (Fe), zirconium (Zn), molybdenum (Mo), vanadium (V), cobalt (Co), and niobium ( The present invention provides a bearing alloy (alloy 2) in which one or more types of Nb) are added in a total amount of 0.2 to 10.0%. Next, we will show the characteristics of various elements added to this alloy: Sn: This is an element added primarily for the purpose of lubrication. This Sn maintains overall mechanical strength while ensuring lubricity to the extent that it is finely dispersed in Al. If it is less than 3%, there will be no lubrication effect, and if it exceeds 40%, the whole will become soft and lose its load bearing capacity. Pb: An element added primarily for lubrication.
It is a material with better lubricity than Sn. Also Sn
When present together with Sn--Pb, a part of the alloying element is formed, and when metal contact occurs due to the presence of an alloy with a lower melting point than Sn and Pb, the lubricity effect is particularly exhibited. If it is less than 0.1%, there is no lubrication effect, and if it exceeds 9.0%, it becomes difficult to cast due to weight segregation. Sb: Has the effect of dispersing Sn and Pb relatively finely, and when present together with Sn and Pb, Sn―Pb―
Create an alloy of Sb to create a soft metal with a high melting point and hardness. This improves the load carrying capacity and high temperature properties of the soft material. In addition, excess Sb creates precipitates such as Al-Sb,
Since this precipitated material is very hard, dispersing it appropriately leads to improved load carrying capacity and improved wear resistance. In this sense, if it is added in an amount exceeding 3.0%, the above conditions will be satisfied, but if it exceeds 10.0%, there will be too much precipitated matter, resulting in a drawback of becoming too hard. Cu, Mg: Strengthens the aluminum base in terms of load resistance and fatigue strength, and prevents a decrease in hardness when the bearing is exposed to high temperatures (over 200℃). There is no effect if it is less than 0.1%, and if it exceeds 3.0%
The Al base becomes too hard and brittle. Si, Ni, Mn, Ti, Fe, Zr, Mo, Co, V, Nb: By casting these elements together with Al (generally added in the master alloy), crystallized substances, precipitates, etc. are formed, and By rolling, the precipitate or hard material is dispersed in the base material. All of these hard materials have a Pickkas hardness of several hundred or more,
Since it is harder than the Al-Sb precipitates mentioned above, it further improves the hardness of the entire alloy, strengthens the Al base, and improves wear resistance. In this sense, if the content of one or more of these elements in an alloy is less than 0.2%, it is ineffective, and if it exceeds 10.0%, it becomes too hard and has the disadvantage of causing wear to the mating shaft. An alloy in which these additive elements are alloyed with each other or with Al may be added. The preferred ranges here are Sn: 6-20%, Pb: 0.5-4.0%, Sb: 3.1-6
%, Cu, Mg: 0.2-2.0%, Si etc.: 0.5-4.0%. Next, the present invention will be explained with reference to Examples. The following table shows alloys 1 to 15 according to the present invention, and alloys 16 to 15 for comparison.
This shows the chemical component values of 18.

【table】

[Table] For Alloys 1 to 15, Al base metal is melted in a gas furnace and then Al-Sb master alloy, Al-Cu master alloy, Al
-Mg master alloy, Al-Si master alloy, Al-Mn master alloy, Al
-Ni master alloy, Al-Ti master alloy, Al-Fe master alloy, Al
- Zr master alloy, Al-Co master alloy, etc. are melted according to the target components, Sn and Pb are finally added, degassed, and cast into a mold, followed by rolling and annealing ( Samples were prepared by repeating heating at 350°C, and the hardness was measured. At this time, the precipitates precipitated in the base metal are sufficiently dispersed in the base metal by the above-mentioned rolling, thereby improving the mechanical properties of the entire alloy. That is, in a cast material having a composition within the range of the present invention, segregation occurs and the material becomes brittle. Figure 4 a is Sb
The segregation state of the Al-Sb alloy in the cast material when the composition is set to 40% and the other compositions are within the range of the present invention is:
Similarly, FIG. 5a is a schematic diagram showing the segregation state of Si when 5.0% of Si is added. Furthermore, Fig. 4b and Fig. 5b are similar to Fig. 4a and Fig. 5a.
This figure shows a state in the present invention in which a cast material is rolled and the precipitated hard material is dispersed in the base material.
Cast materials in which hard materials exist in a segregated state tend to have poor mechanical properties such as cracking and brittleness in the segregated portions, and generally cannot be put to practical use if the above addition amount exceeds 3%. becomes difficult. In contrast, in the present invention, by adding more than 3% of the above elements, many hard substances are actively precipitated, and this is further rolled to disperse the segregated hard substances in the base material (fourth (see Figure b and Figure 5b), thereby improving mechanical properties such as brittleness and making it possible to put it into practical use. Next, for the samples whose hardness was measured above, these alloys were bonded to a backing steel plate to form a bimetallic material, which was annealed and then processed into a flat bearing and subjected to a wear test. Also alloy 16-1
In No. 8, a comparative alloy was prepared using the same manufacturing method as the above-mentioned alloy and used as a sample, and the same test was conducted. FIG. 1 shows the results of measuring the hardness of Alloys 1 to 18 using Witzkers hardness.
As is clear from these graphs, Alloys Nos. 1 to 15 according to the present invention have the same or higher hardness than Comparative Alloys Nos. 16 to 18. This is due to hard substances such as precipitates. In addition, especially alloys to which Cu and/or Mg are added show little decrease in hardness even at high temperatures, as is clear from FIG. 2, where the hardness was measured at elevated temperatures. This means that the bearing has load resistance and wear resistance even when used at high temperatures. Next, FIG. 3 shows alloys 3, 7, 9, and
This figure shows the results of wear tests conducted on Alloy No. 12 and comparative alloys No. 16, 17, and 18.
In this experiment, the shaft rotation speed was 1.000 rpm, and the shaft material was
Using S55C hardened material, the shaft surface roughness is 1μm, and under forced lubrication at a constant oil temperature (120℃),
It is a graph showing the results of measuring changes in the amount of wear when the load is increased. According to this graph, compared to alloys 16, 17, and 18, 3,
Nos. 7, 9, and 12 were found to have extremely low amounts of wear, indicating excellent wear resistance. This is recognized to be the effect of hard materials dispersed in the Al ground. In addition, in the alloy composition according to the present invention, it goes without saying that Al contains impurities that cannot be avoided by ordinary refining techniques. As mentioned above, the Al-Sn bearing alloy according to the present invention has a large amount of hard material dispersed in the base material by rolling, so it is less brittle than an alloy in which a large amount of hard material is segregated. It is possible to improve the mechanical properties such as, etc., and to make it possible to put it into practical use. Also Si, Ni, Mn, Ti, Fe, Zr, Mo, Co,
By adding V and Nb, the wear resistance can be further improved within a practical range.

[Brief explanation of the drawing]

FIG. 1 is a graph blotting the hardness of the Al--Sn bearing alloy according to the present invention and a comparative bearing alloy of the same type. FIG. 2 is a graph blotting changes in hardness due to temperature changes. FIG. 3 is a graph showing how the amount of wear changes when the load is similarly increased on the steel shaft. Figure 4a shows the segregation state of the Al-Sb alloy when Sb is 4.0% and other compositions are within the range of the present invention, and Figure 4b shows the hard material segregated by rolling the same figure a. A schematic diagram showing a state in which the particles are dispersed in the material. Figures 5a and 5b are schematic diagrams corresponding to Figure 4a and b when 5.0% Si is added, respectively.

Claims (1)

[Scope of Claims] 1. An aluminum bearing consisting of 3 to 40% tin, 0.1 to 9.0% lead, more than 3 to 10% antimony, 0.1 to 3.0% copper and/or magnesium, and the balance substantially aluminum by weight. 1. An aluminum bearing alloy characterized by hard substances precipitated in a base material or dispersed in the base material by rolling. 2 By weight, tin 3-40%, lead 0.1-9.0%, more than 3 antimony but not more than 10%, copper and/or magnesium 0.1-3.0%, silicon, nickel, manganese, titanium, iron, zirconium, molybdenum, cobalt, An aluminum bearing alloy consisting of one or more of vanadium and niobium in a total of 0.2 to 10.0% and the balance substantially aluminum,
An aluminum bearing alloy characterized in that the hard material is precipitated in the base material or dispersed in the base material by rolling.