JPH0320451B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to an aluminum bearing alloy, and more particularly to an aluminum bearing alloy with increased seizure resistance and fatigue strength. ``Prior Art'' Conventionally, efforts have been made to improve high-temperature hardness, seizure resistance, or fatigue strength of aluminum bearing alloys (Japanese Patent Publication No. 12131/1983,
(Japanese Patent Publication No. 58-14866, Japanese Patent Application Publication No. 87917-1987, Japanese Patent Application Publication No. 35744-1987, etc.). Of the above cited publications, the latter three are related to the applicant's application, and among them, the following two
Two publications disclose inventions similar to the present invention. In other words, the aluminum bearing alloy disclosed in Japanese Patent Publication No. 58-14866 contains Sn3.5~35% and Cr0.1~35% by weight.
1%, Si1~10%, Mn, Sb, Ti, Ni, Fe, Zr,
1 to 10% of one or more of Mo and Co, the total amount of which is 10% or less, and the balance is Al, and if necessary, 3.0% or less of Cu and/or Mg,
Alternatively, in place of or in addition to this, Pb, Bi,
One or more types of In are added in an amount of 9% or less. Furthermore, the aluminum bearing alloy disclosed in Japanese Patent Application Laid-open No. 56-35744 contains 3 to 40% Sn, 0.1 to 9% Pb, and
Sb0.1~less than 3%, Si, Ni, Mn, Ti, Fe, Zr,
A total of one or more of Mo, Co, V, and Nb
The balance is 3.0 to 10% Al, and 0.1 to 3.0% Cu and/or Mg is added as necessary. "Problems to be Solved by the Invention" Each of the above aluminum bearing alloys has superior performance compared to conventional ones.
Many subsequent experiments with various combinations of elements as described above revealed that there are more effective combinations. "Means for Solving the Problems" That is, the aluminum bearing alloy according to the first invention of the present application contains, in weight percent, 3 to 20% Sn, 0.1 to 1% Zr,
Si1.5-8%, Cu and/or Mg0.2-2%, V,
At least one of Nb, Mo, and Co, with the total amount of Zr exceeding 0.1% and up to 1%, and the balance being Al
It consists of In addition, the aluminum bearing alloy according to the second invention of the present application has Sn3 to 20%, Zr0.1 to 1%, and
Si1.5~8%, Cu and/or Mg0.2~2%, Pb0.1
~5%, at least one of V, Nb, Mo, and Co, the total amount with Zr is more than 0.1% to 1%, and the balance is Al. "Function" First, in the aluminum bearing alloy of the present invention,
Sn is an element added primarily for the purpose of lubrication; if it is less than 3%, it has no lubrication effect, and if it exceeds 20%, the entire material becomes soft and the load bearing capacity is reduced. Next, the amount of Zr added to the aluminum bearing alloy of the present invention is 0.1 to 1%. If it is less than 0.1%, the improvement in strength at high temperatures described below cannot be expected;
If it is added in excess of this amount, too many precipitates will form and the bearing alloy will become too hard. Zr mentioned above lowers the recrystallization temperature of Al by solid solution in Al, and increases the hardness of Al base by itself, but at the same time, it can also be cast by rolling several times. Hardness increases over time. Increasing the recrystallization temperature is effective in maintaining stable mechanical properties even in the high-temperature range that internal combustion engine bearings are exposed to. Improves bearing strength in high temperature areas. In addition, precipitates that precipitate beyond the solid solubility limit exist stably even at high temperatures, and finely dispersing this compound helps maintain high-temperature hardness, so dispersing an appropriate amount of this compound has a positive effect. Furthermore, if the above precipitates exist finely dispersed in the Al base metal, the intermetallic compounds cannot be directly
Preventing the movement of Al grain boundaries, that is, the coarsening of Sn particles,
This leads to keeping the Sn particles, which have been refined through repeated rolling and annealing, as they are.
It has the various effects mentioned above. In addition, the fact that Sn particles remain fine and exist in the Al base metal also means that Sn particles, which have a low melting point of 232°C,
It is also effective for preventing the elution phenomenon of particles at high temperatures. It is known that Cr also has this effect (Japanese Unexamined Patent Publication No. 53-87917), but in the case of Cr, Sn begins to coarsen after 30 minutes at 450°C, whereas in the case of Zr
In the case of
It was found that Cr had a better effect than Cr. Next, Si is added to the aluminum bearing alloy of the present invention for the purpose of improving seizure resistance and wear resistance, and the amount of Si added is 1.5 to 8%. If it is less than 1.5%, the amount of precipitation is small and no effective improvement in wear resistance is observed.On the other hand, if it is added in excess of 8%, too much precipitate is deposited, resulting in poor rolling properties and making it difficult to repeat rolling and annealing. This is because the miniaturization of Sn can be prevented. Si itself has high hardness and excellent castability, and its precipitates are extremely hard, reaching approximately 1000 on the Bitkers hardness scale, so they significantly reduce bearing wear due to sliding with the shaft. be able to. For bearings that are softer than the shaft, the bearing surface will be cut, and as this situation progresses, the bearing surface will become rougher, the clearance between the shaft and the bearing will increase, and no oil film will form, causing damage to the shaft and bearing. Direct contact, that is, metal contact, often occurs, leading to seizure, but since the above precipitates are harder than hardened steel shafts and cast iron shafts, it is possible to improve wear resistance and durability when using cast iron shafts. Particularly effective in improving seizability. In this way, Si is originally added to improve the seizure resistance and wear resistance of bearings, especially the seizure resistance of cast iron shafts, but a trace amount of Si
has the effect of shortening the time for fine precipitation of Zr during post-processing heat treatment. In other words, the Al-Zr binary system requires aging treatment (heat treatment) at 450° C. for several tens of hours or more, but if Si is added to the aging treatment, it can be done in one to several hours. Next, the amount of Cu and/or Mg added is 0.2 to 2%.
This is added to further reduce the decrease in strength at high temperatures. If it is less than 0.2%, the effect cannot be expected to be significant, and if it is added in excess of 2%, it becomes too hard, inhibiting rolling properties, and also reduces corrosion resistance. This effect of Cu and/or Mg on strength is due to Zr
It is produced by adding Cu and/or at the same time.
Mg alone cannot be expected to have the effect of increasing strength at high temperatures. In other words, when Cu and/or Mg are added to Al, the strength during rolling increases significantly, and even at the same rolling rate, the increase in strength is remarkable compared to Al materials with other elements added, but at temperatures near 200℃ It easily softens when heated to a high temperature, and cannot be expected to maintain its strength at high temperatures. On the other hand, when Zr and Cu and/or Mg are added simultaneously, the strength increased during rolling due to the addition of Cu and/or Mg does not decrease much due to the effect of Zr addition even during annealing. Therefore, an aluminum bearing alloy with high strength can be obtained, and its strength does not deteriorate as much as in conventional alloys of this type even at high temperatures. Furthermore, the present invention provides at least one of V, Nb, Mo, and Co, and the total amount with Zr exceeds 0.1%.
%. That is, the amount of these components added is from a trace amount to less than 1%. The purpose of these additions is to increase the recrystallization temperature of the Al base and to prevent these intermetallic compounds from moving Al grain boundaries. If the total amount with Zr exceeds 1%, coarse precipitates will be generated, which will have a negative effect on strength, elongation, and fatigue.In particular, when Sb is added, coarse precipitates of A1Sb will be generated, so its addition is undesirable. There was found. The second invention of the present application is the first invention described above,
Furthermore, 0.1 to 5% of Pb is added to improve the performance of Sn as a lubricating metal.
Excellent effects are observed when Zr and Si are added simultaneously. That is, when Pb is added, the Sn in the Al-Sn alloy forms a Sn-Pb eutectic alloy (melting point 183°C), which lowers the melting point, which is disadvantageous against fatigue.
However, when Zr, Si, and Pb are added at the same time, the Sn-Pb eutectic structure becomes fine due to the fineness effect of Zr, which compensates for the disadvantage of low melting point and improves fatigue resistance. decrease is suppressed.
Furthermore, the coefficient of friction becomes more stable and the seizure resistance becomes extremely good. If the amount of Pb added is less than 0.1%, the effect of improving the performance of Sn as a lubricating metal cannot be expected;
If added in excess of this amount, it becomes too soft and fatigue resistance deteriorates. Examples Examples of the present invention will be described below.
The table shows the components and results of various tests for Alloys 1 to 15 according to the first invention, Alloys 16 to 30 according to the second invention, and Comparative Materials 31 to 40. Also the second
The table shows alloys 41 to 46 according to the first invention and comparative materials 47 to 52.
This table shows each component and the results of various tests.

【table】

【table】

【table】

[Table] Each test was conducted under the following test conditions. (Tensile test) Instron type tensile tester tensile speed: 5 mm/min Test piece: JIS No. 6 (seize test) Journal type seize tester rotation speed: 1000 rpm Shaft diameter: 52 mm diameter Shaft: FCD70 (Hv230-250) s50C quenched ( Hv500
~600) Lubricating oil: SAE10W-30 Oil temperature: 140±5℃ Load: Increase by 50Kg/ ^cm2 every 30 minutes (Sienck fatigue test) Sienck flat plate bending tester 3000 cycles/min Fatigue after 10 ⁷ times Atmosphere temperature for measuring strength: 175±5℃ (reciprocating dynamic load fatigue test) Soda type dynamic load tester rotation speed: 2100~3100rmp Shaft diameter: 40mm diameter Shaft: S50C quenched (Hv500~600) Lubricating oil: SAE10W-30 oil Temperature: 140±5℃ Load: 40Kg/cm every ² times 10 Measure fatigue strength after ⁷ times (rotating load fatigue test) Rotating load tester rotation speed: 8000rmp Surface pressure: 300Kg/cm ² shaft diameter: 40mm diameter Shaft: S50C quenching (Hv500~600) Lubricating oil: SAE10W-30 Oil temperature: 120~160℃ 10 Measure the critical temperature of the back surface of the bearing that can withstand ⁷ tests.As shown in the test results in Tables 1 and 2,
The products of the present invention have obtained good results compared to comparative materials, especially the products of the present invention 31 to 31 containing Zr and V.
36 is a comparative material 37 to 39 with Cr added instead.
Good results were obtained for comparison materials 40 to 42 containing Sb and Sb. As shown in Table 1, products 16 to 30 of the present invention according to the second invention to which Pb is added are more Good results have been obtained. "Effects of the Invention" As described above, according to the present invention, it is possible to achieve the effects of further improving high-temperature strength, improving seizing resistance, and increasing fatigue strength compared to conventional methods.

Claims (1)

[Claims] 1% by weight: Sn3~20%, Zr0.1~1%, Si1.5
~8%, Cu and/or Mg0.2~2%, V, Nb,
At least one of Mo, Co, and the total amount with Zr
Aluminum bearing alloy consisting of more than 0.1% up to 1%, and the balance being Al. 2 Weight%: Sn3~20%, Zr0.1~1%, Si1.5
~8%, Cu and/or Mg0.2~2%, Pb0.1~5
%, at least one of V, Nb, Mo, and Co,
An aluminum bearing alloy in which the total amount of Zr is more than 0.1% to 1%, and the balance is Al.