JPS602643A - Die casting aluminum alloy with superior wear resistance - Google Patents

Abstract

PURPOSE:To obtain a die casting Al alloy with superior wear resistance and seizing resistance by adding specified percentages of Si, Cu, Fe and Mg to Al. CONSTITUTION:An Al alloy consisting of, by weight, 15.0-22.5% Si, 5.5-10.5% Cu, 0.8-1.5% Fe, 0.85-1.5% Mg and the balance Al with ordinary inevitable impurities or further contg. 0.002-0.025% P is prepd. The prepd. alloy is a die casting Al alloy suitable for use as the material of a sliding member which ensures a highly favorable sliding state when lubricating oil with low viscosity as well as lubricating oil with high viscosity is used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aluminum alloy for die casting that exhibits excellent wear resistance and seizure resistance.

In recent years, various aluminum casting alloys have been widely used as sliding members of various machines. Conventionally known aluminum alloys for die casting used for this type of sliding member include A
A standard 3 pieces 2~0. 8% by weight, Mg o. 8~
Although this alloy contains 1.2% by weight, the above-mentioned sliding members manufactured using this alloy had the following drawbacks. In other words, lubricating oil is generally used in the sliding parts of machinery to form a uniform thin film on the sliding surface in order to prevent wear and seizure of the sliding surface. As such lubricating oils, oils with higher viscosity than conventional ones (70 to aoc.
sT) was commonly used. However, when using such a highly viscous lubricating oil, the viscosity naturally increases during cold winter months, resulting in excessive initial sliding torque, starting troubles, and machine problems. It is desirable to use low viscosity lubricating oils (less than about 70 C S 'T) because they interfere with favorable operation. However, when the above-mentioned low-viscosity lubricating oil is used in the conventional sliding member using an aluminum alloy as described above, seizure often occurs on the sliding surface.

This caused significant wear, making it impossible to obtain a favorable sliding condition.

The present invention solves the above-mentioned drawbacks and is suitable for die-casting aluminum for sliding members that can ensure a sufficiently favorable sliding condition not only when using high-viscosity lubricating oil but also when using low-viscosity lubricating oil. 5115. O~22.5 weight q6,
A wear-resistant material containing 5.5 to 10.5% by weight of Cu, 8 to 1.5% by weight of FeO, 0.85 to 1.5% by weight of Mg, and the balance At and normal unavoidable impurities. The present invention provides an excellent aluminum alloy for die casting, and an aluminum alloy for die casting that further contains P in an amount of 0.002 to 0.025i, and has excellent wear resistance.

The reasons for limiting the components contained in the alloy of the present invention will be described below.

Si is used to form primary silicon that imparts wear resistance, and if its content is less than 15.0% by weight, it will not be possible to impart sufficient wear resistance to the sliding member. Burn-in occurs. If it exceeds 22.5% by weight, the primary silicon becomes coarse, and when it slides with the mating member, some of the coarse primary silicon will break off, and the crushed primary silicon will remain on the sliding surface. This is undesirable because the thin film of lubricating oil is further destroyed and seizure is increased. Especially when using sliding parts with extremely low viscosity lubricating oil, S
The content of t is preferably 18.5 to 22.5% by weight.

Cu has the effect of strengthening the matrix, preventing the lifting of primary silicon during sliding, and preventing the destruction of the thin film of lubricating oil due to primary silicon.If the content is less than 5.5% by weight, The effect of preventing the destruction of the lubricating oil thin film due to matrix reinforcement is small.

Therefore, seizure tends to occur, which is undesirable. If it is more than 10.5% by weight, casting cracks occur during die casting, and elongation also decreases, which impairs toughness and makes accidents such as breakage more likely, which is undesirable. Especially when using a sliding member using extremely low viscosity lubricating oil, the Cu content should be 6.5 to 10.5% by weight.
It is preferable that

M strengthens the matrix in the same way as Cu, and is expected to have the same effect as Cu, but if it is less than 0.855 weight, the effect of strengthening the matrix will be small and seizure will easily occur, which is undesirable. , and it is 1.5 times i
If it is -1 or more, cavities will occur in the casting when die casting is performed, and the oil film will be destroyed by the irregularities of the cavities, making seizure likely to occur, which is undesirable.

Fe is used to prevent seizure of the die during die casting, and if the Fe content is less than 0.8% by weight, the above-mentioned effect will be reduced and seizure will easily occur, which is undesirable. If it exceeds 5% by weight, elongation decreases and toughness is impaired, which is undesirable because accidents such as breakage are likely to occur.

P is for refining primary silicon.

When the content of P is 0.002% by weight or more, the effect of refining appears, and as a result, the destruction of the thin film of the lubricating oil due to relatively large primary silicon, which would occur when P was not added, is suppressed. This is preferable because seizure is less likely to occur. Further, even if it exceeds 0.025% by weight, no significant effect of finer graining is observed, so the upper limit is kept at 0.025% by weight.

Furthermore, in the alloy of the present invention, Ti is 0.3% by weight or less and B is 0.3% by weight or less.
15% by weight, 0.10% by weight of Zr, and impurities inevitably contained in the process of manufacturing the shrub invention alloy,
For example, even if Mn, V, etc. are contained, it is not inconvenient because it does not impair the wear resistance and seizure resistance of the alloy of the present invention.

Next, in order to further clarify the present invention, one example will be described in detail.

Test pieces (50φ x 5t) were manufactured by die-casting various aluminum alloys shown in Table 1. The surface was polished with sandpaper to a center line average roughness of 0.5F. As a counterpart test piece to the test piece prepared in this way, a 5CR420 (JIS standard) carburized and quenched cylindrical test piece (inner diameter 20V, outer diameter 25φ, length 16 mm, center line average roughness of contact surface 0. 2Fm, Hv600~800
．． The test was carried out using a Flictron friction and wear tester using a contact area of 1-). The lubricating oil used was a lubricating oil (27C8T) having an extremely low viscosity among low-viscosity lubricating oils, and was tested under severe test conditions.

The test conditions are shown below.

Sliding speed: 1.2 m/sec Oil temperature: 15-30°C Surface pressure/time: Keep the surface pressure at 300 kyct/i and continue sliding for 30 minutes.

When the sliding torque exceeded 30 kl-cm, it was assumed that seizure had occurred on the sliding surface and the test was discontinued. For those in which seizure did not occur, the amount of wear after the test was measured.

Ten samples were used for each test.

The results are shown in Table 1.

As is clear from Table 1 in the margin below, when it comes to the occurrence of burn-in, 9
The number of seizure occurrences of the alloys of the present invention (sample numbers 1 to 4) is 0 to 1.
On the other hand, the comparative alloys (sample numbers 5 to 8) have 4 to 1
Since 0 pieces were generated and 9 pieces were generated in the AA392 alloy, it can be seen that the alloy of the present invention has superior seizure resistance compared to the comparative alloy and the AA392 alloy. Furthermore, regarding the amount of wear of the samples in which no seizure occurred, the amount of wear of the nine invention alloys is less than 1 m1, whereas the amount of wear of the comparative alloys (sample numbers 5 and 6) and the A 392 alloy (sample number 9) The amount of wear was as large as 10 to 60 mf, indicating that the alloy 9 of the present invention has superior wear resistance compared to sample No. 5°6.9.

As explained above, the alloy of the present invention is particularly useful when using low-viscosity lubricating oil, as it has less seizure and no significant wear than conventional alloys. This alloy is ideal as an alloy for sliding parts of drive devices that require the use of low-viscosity lubricating oil in cold weather, for example, shift forks, and is an industrially excellent and valuable invention. .

Patent Applicant: Tamoto Light Metal Co., Ltd. Toyota Motor Corporation Page 1 continued @ Inventor: Yoshio Fuwa, 1 Toyota-cho, Toyota City, Toyota Motor Corporation, District Inventor: Hideo Ishikawa, 1-Toyota-cho, Toyota City, Toyota Motor Corporation. Applicant Toyota Motor Corporation 1 Toyota-cho, Toyota City

Claims (1)

[Claims] (11S115.0-225 weight q6, Cus, 5
~10.5% by weight, Fe 0.8~1.5% by weight,
An aluminum alloy for die casting with excellent wear resistance, containing MgQ, as ~ 1.5% by weight, and the balance At and normal unavoidable impurities. +21 5i15.0-22.5% by weight, Cu5.5
~10.5% by weight, Fe 0.8~1.5% by weight,
Mg 0.85-165% by weight, P 0.002-0.
An aluminum alloy for die casting with excellent wear resistance, containing 0.25% by weight and the remainder At and normal unavoidable impurities.