JPS5821016B2 - wear-resistant aluminum bronze - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to wear-resistant aluminum bronzes, and more particularly to aluminum bronzes containing iron silicides.

; To improve the wear resistance of copper alloys, disperse soft phases such as lead, hard phases such as carbides, nitrides, and silicides, or solid lubricants such as graphite and molybdenum disulfide in copper alloys. An attempt was made.

It was also confirmed that wear resistance was significantly improved by dispersing manganese silicide in brass.

Brass containing this manganese silicide is disclosed in U.S. Patent No. 3,33
No. 7,335.

The effect of manganese silicide on improving wear resistance has also been confirmed for bronze and aluminum bronze, and several types of copper alloys containing manganese silicide have been put into practical use.

It was also confirmed that manganese silicide was mainly dispersed in the form of Mn5S13.

However, there have not yet been sufficient reports on the effects of manganese silicide on copper alloys.

Therefore, we independently investigated the effects of manganese silicide.

As a result, when manganese silicide crystallizes in the hypoeutectic region of the pseudo-binary phase diagram of copper alloy matrix and manganese silicide, the wear resistance is actually lower than when it does not contain manganese silicide. This was confirmed.

It was also found that in the hypoeutectic region, as the amount of manganese silicide increases, the wear resistance decreases.

On the other hand, in the hypereutectic region, the effect of manganese silicide was significantly observed, and it was confirmed that the greater the amount of manganese silicide, the more the wear resistance was improved.

However, on the other hand, it was found that the elongation rate decreased significantly.

As an example, an alloy in which manganese silicide is contained in a hypereutectic region in brass has an elongation rate of 10 or less as cast, and is extremely brittle.

It has also been found that when a copper alloy containing manganese silicide is slid under high surface pressure, it tends to wear out the mating material as well.

The decrease in elongation rate is unavoidable because it contains hard manganese silicide, but it is also caused by the fact that manganese silicide crystallizes as hexagonal columnar crystals.

It can be expected that the elongation rate will increase if the crystals are crystallized in a spherical or nearly spherical shape instead of a hexagonal columnar crystal.

Furthermore, if the eutectic point in the pseudo-binary phase diagram of the copper alloy matrix and manganese silicide can be moved to the side with less manganese silicide, the amount of manganese silicide required for wear resistance can be reduced. Therefore, it becomes possible to suppress a decrease in elongation rate.

However, in order to crystallize manganese silicide in a spherical or nearly spherical shape, a new technique is required, which is almost impossible at present.

For this reason, we decided to find compounds that provide wear resistance comparable to manganese silicides and crystallize in spherical or nearly spherical shapes, such as carbides, nitrides, and silicides.

In addition, it was decided to select a combination of a compound and a copper alloy matrix such that the eutectic point of the copper alloy containing the above compound is on the side where the amount of the compound is as small as possible.

The wear resistance was set to be equal to or higher than that of an alloy containing manganese silicide in brass, and the elongation was targeted to be 10 modulus or higher as cast.

In addition, if the mechanical strength of the obtained copper alloy is low, the friction surface layer will flow when used as a sliding part, making it easy to cause adhesive wear.

The mechanical strength of the copper alloy is 50% in tensile strength as cast.
kg/- or more was used as the standard.

It was also hoped that the amount of wear on the mating material would be less than that of brass with manganese silicide dispersed in it.

The object of the present invention is to separate manganese silicide into brass.

It is an object of the present invention to provide a copper alloy which has wear resistance comparable to that of a dispersed alloy, and has a tensile strength of 50 kg/mA or more and an elongation coefficient of 10 or more as cast.

The present invention contains 4 to 12% by weight of aluminum, 0.1 to 1% by weight of solid solution silicon, and produces iron silicification in a pseudo-binary phase diagram of copper-aluminum alloy phase and iron silicide. It is an aluminum bronze containing a eutectic composition or more and a weight ratio of 10 or less, with the remainder being substantially copper.

The aluminum bronze of the present invention has better wear resistance and greater elongation than an alloy containing sunga silicide in brass.

In addition, as cast, the tensile strength is 50 kg/- or more, and the elongation rate is 1.
Has 0 or more units.

Furthermore, compared to alloys containing manganese silicide in brass, there is less wear on the mating material.

Tetrairon silicide was chosen as a replacement for manganese silicide.

Similar to manganese silicide, this iron silicide has the effect of improving wear resistance, and when it coexists with solid solution silicon, it crystallizes as spherical objects or fine dendrites, so its amount should be increased. It was also found that the elongation did not decrease significantly.

It has also been found that when the copper alloy matrix is aluminum bronze, the eutectic point in the pseudo-binary phase diagram between the copper alloy matrix phase and the amount of iron silicide is located on the side with the least amount of iron silicide. Ta.

It has also been found that in this case, wear resistance is improved by crystallizing iron silicide in the hypereutectic region.

Therefore, when iron silicide is contained in aluminum bronze, wear resistance and elongation are the best.

The iron silicide crystallized in aluminum bronze has the form Fe5S+.

The composition of iron silicide in the aluminum bronze actually produced was 80 to 84% iron by weight and the remainder silicon.

In the present invention, the appropriate amount of aluminum is 4 to 12% by weight, similar to that contained in general aluminum bronze.

If the aluminum content exceeds 4% by weight, the tensile strength as cast will not exceed 50 kg/m4, and if the aluminum content exceeds 12% by weight, it will become brittle due to precipitation of the γ2 phase, making it unsuitable for practical use.

The effect of aluminum on mechanical strength is 8-9.5
It appears best when weighing.

The eutectic point in the quasi-binary state of the aluminum alloy phase of copper - 8 to 9.5 weight percent and the amount of iron silicide is located 1 to 2 weight points above the iron silicide concentration side.

When the amount of aluminum is more than this, the eutectic point shifts to the side where there is less iron silicide, and conversely, when the amount of aluminum is less than this, the eutectic point shifts to the side where there is more iron silicide.

However, the eutectic point changes only slightly as the amount of aluminum increases or decreases.

The effect of iron silicide on wear resistance is noticeable when the amount of iron silicide is above the eutectic point, usually 2% by weight or more, but it must not exceed 10% by weight (G).

If the content of iron silicide exceeds 10% by weight, the elongation rate as cast may be lower than 10 when the amount of aluminum is large.

To achieve a good balance between tensile strength and elongation,
It is desirable that the iron silicide has a weight ratio of about 4.2 when the weight is 3 to 5.

When aluminum bronze, which is made of iron silicide, aluminum, and the balance is copper, is subjected to wear tests, the amount of wear sometimes increases abnormally.
Moreover, the amount of wear on the mating material may increase.

When the worn particles and the worn surface were observed using a scanning electron microscope, the cause of the abnormal wear was that the iron silicide directly under the friction surface easily detached from the Ma I-IJ Lux, and the detached iron silicide was crushed. It was found that the crushing particles were for grinding the mating material and aluminum bronze.

If iron silicide were crystallized as hexagonal columnar crystals or rod-shaped crystals like manganese silicide, it would be prevented from separating from the matrix, but this is not suitable because the elongation is inevitably reduced significantly.

Therefore, the matrix is strengthened and the iron silicide is released from the matrix.

We considered making it less crowded.

This was achieved by solid solution of silicon in the matrix.

In addition, it has been found that by incorporating silicon into a solid solution, iron silicide becomes finer spherical or dendrite crystals, and the decline in elongation is suppressed. solid solution to increase the mechanical strength of the matrix.

Strengthening with solid solution silicon makes it difficult for iron silicide to separate from the matrix.

The amount of solid solution silicon should be less than 1 factor by weight; if it exceeds 1 factor by weight, the elongation rate as cast may become less than 10 factors if the amount of aluminum or iron silicide is large.

In the aluminum bronze of the present invention, the tensile strength reaches a peak when the amount of silicon in solid solution is around 1 weight, and decreases when the amount exceeds that amount.

Moreover, the peak of elongation 1 occurs when the amount of solid solution silicon is 0.2 to 0.
It is located at the 4th weight section, and if it exceeds it, it will decrease.

In order to balance tensile strength and elongation, the amount of solid solution silicon is desirably in the range of 0.1 to 0.6 weight ratio, particularly 0.4
A range of 0.5 to 0.5 weight coefficient is preferred.

When used in applications that require particularly high elongation, it is desirable that the amount of solid solution silicon be 0.2 to 0.4% by weight, and high tensile strength is particularly required. When used in applications where the amount of solid solution silicon is 0.8~
It is desirable to set it to 1% by weight.

Iron is essential for creating silicides and providing wear resistance and high strength.

Since iron is added so that the amount of silicon in solid solution is 0.1 to 1% by weight, there is no calculated amount of iron in solid solution.

In particular, the amount of iron added is preferably 6% by weight or less.

The aluminum bronze of the present invention can contain nickel and manganese, which are included in general aluminum bronze to increase strength.

These amounts should be 1 to 7 parts by weight of nickel and 1.5 parts by weight of manganese, similar to those contained in general aluminum bronze.

Further, although aluminum bronze may contain zinc as an impurity, the total amount of zinc and manganese should not exceed 2 parts by weight.

The aluminum bronze of the present invention can be used as it is cast or by forging an ingot.

Moreover, it can also be used after heat treatment.

Applications include sliding parts of rolling mills, machine tools, marine equipment, automobile equipment, etc., and can be applied to gears, bearings, worm wheels, rolling mill internal threads, slipper metals, etc.

Example 1 Thirteen types of aluminum bronze were melted in the atmosphere in a high frequency induction heating furnace without using flux, and then cast.

The tensile strength and elongation of the as-cast specimens were then measured.

In Table 1, which shows the chemical composition, tensile strength, and elongation of aluminum bronze produced, A2-5, 8-
9 and 12 are alloys of the present invention.

A1 to A5 were sand cast, and A6 to A13 were die cast.

FIG. 1 shows the relationship between the amount of solid solution silicon and the tensile strength and elongation for Al~5 aluminum bronze, and the effect of solid solution silicon can be clearly seen.

That is, the tensile strength is increased by containing solid solution silicon.

Furthermore, the elongation tends to increase when the amount of solid solution silicon reaches around 0.3 weight coefficient.

The highest value of tensile strength is achieved when the amount of solid solution silicon is 0.8 weight factor, and this high value is maintained even when the amount of solid solution silicon is 1.0 weight factor.

In order to achieve a balance between tensile strength and elongation. The amount of solid solution silicon is 0.1 to 0.6 by weight, especially 0.4 to 0.5
I mentioned earlier that it should be in charge of weight, but this is the first step.
It is easy to understand from the figure.

A6 is the most common conventional aluminum bronze containing only aluminum in steel, and 16.7° is a steel containing iron silicide.

It is clear that by including iron silicide in aluminum bronze, the tensile strength increases, but on the other hand, the elongation decreases.

FIG. 2 summarizes the characteristics of A6 and A8-13 aluminum bronzes and shows them in relation to the amount of iron silicate and oxides.

As the amount of iron silicide increases, the tensile strength increases, but the elongation decreases.

A low elongation rate is recorded when the amount of iron silicide is 5% by weight, but this is because it exhibits the characteristics of A and 10, which do not contain solid solution silicon. Figure 3 shows All aluminum without solid solution silicon. For bronze, and Figure 4 is for A3 aluminum bronze containing solid solution silicon;
This figure shows the shape of iron silicide particles.

The iron silicide was extracted by dissolving the matrix in an aqueous nitric acid solution.

Further, the shape of the iron silicide particles was photographed using a scanning electron microscope under magnification of 500x.

From these photographs, it is clear that there are differences in the shape and size of iron silicide particles between those containing solid solution silicon and those not containing solid solution silicon.

When the chemical composition of these iron silicides was analyzed using an X-ray microanalyzer, it was found that the composition was very close to that of Fe5Sl, and furthermore, it contained only small amounts of nickel and aluminum.

Example 2 In order to compare the wear resistance of the aluminum bronze of the present invention with a conventional wear-resistant copper alloy and an iron silicide-dispersed aluminum bronze containing no solid solution silicon, a surface pressure of 500 kg/ff was applied.
A reciprocating sliding wear test was conducted under the conditions of 1, average friction speed of 0.2 m/s, and turbine oil lubrication, with the mating movable piece being JIS standard 545C.

The copper alloys used in the test are A3, A5, and A3 in Table 1.
Al O.

5AE430. JIS standard ALBC3, JIS standard PB
Manganese silicide (Mn, 5i3) in C2B and β brass
is dispersed by a weight coefficient of 5.2.

The test results are shown in Figure 5.

With the exception of aluminum bronze containing iron silicide and β-brass containing manganese silicide, adhesion occurs over a wide area, and the protrusions of the grown adhesion cause aprecipitation wear, resulting in a large amount of wear and damage to the opponent. Material wear also increased.

Aluminum bronze containing iron silicide and brass containing manganese silicide had less wear than these and also had less wear on the mating material.

An example of the wear amount of the mating material is shown in Table 2.

This is the amount of wear after sliding for 101 cm, and it is clear that Ni-3 and Ni-5, which contain solid solution silicon, are much less than other copper alloys.

Example 3 The relationship between the critical surface pressure that causes seizure and the friction speed was determined for the aluminum bronze of the present invention and a conventional copper alloy.

The alloys applied to the test are A3 and A7.5AE4 in Table 1.
30, JIS standard BC2, JIS standard ALBC2 and manganese silicide 5.2 weight coefficient dispersion β brass.

The results are shown in Figure 6. The lower side of the curve means that no burn-in occurs, and the upper side means that burn-in occurs.

Also, the higher the surface pressure of the curve, the less likely it is to seize.

It is clear from FIG. 6 that the aluminum bronze of the present invention is less likely to seize than other copper alloys.

As explained above, the aluminum bronze of the present invention containing iron silicide and solid solution silicon has extremely excellent wear resistance and causes less wear on the mating material.

In addition, the tensile strength and elongation are also very high.

Therefore, it is suitable as a sliding member of mechanical equipment.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram showing the relationship between tensile strength and elongation and the amount of solid solution silicon for aluminum bronzes A1 to A5 in Table 1.
Figure 3 is a characteristic diagram showing the relationship between tensile strength and elongation and iron silicide content for aluminum bronze.
Scanning electron micrograph showing the shape of iron silicide particles, No. 4
The figure is a scanning electron micrograph showing the shape of iron silicide particles in Table 1 A7, Figure 5 is the wear test results of various copper alloys, the characteristic diagram showing the relationship between wear amount and friction distance, and Figure 6 is the FIG. 2 is a characteristic diagram showing the relationship between surface pressure and friction speed of a copper alloy.

Claims (1)

[Scope of Claims] 14 to 12 weight percent aluminum, 0.1 to 1 weight surface soluble silicon, and iron silicide; the remainder substantially consists of copper, and the content of the iron silicide is A wear-resistant aluminum bronze characterized by having a temperature above the eutectic point in a pseudo-binary phase diagram of a copper-aluminum alloy phase and an iron silicide and a weight below 10 weight. 24 to 12% by weight aluminum, 0.1 to 1% by weight surface soluble silicon, 1 to 7% by weight nickel, and iron silicide, with the remainder substantially consisting of copper, and the content of the iron silicide is 1. A wear-resistant aluminum bronze characterized by being above the eutectic point in a pseudo-binary phase diagram of a copper-aluminum alloy phase and iron silicide, and having a weight of 10 weight or less.