DE2262696A1 - ALUMINUM / LEAD BLOCK OD. DGL. AND METHOD OF MANUFACTURING THE SAME - Google Patents

Description

Aluminum / lead block or the like and method for producing the same

The invention relates to an aluminum / lead block or other body consisting of an aluminum / lead alloy and manufactured from this block or body La ^ er and other products. The invention also relates to a method of making such a block or other body.

The block or the like according to the invention is suitable especially for the manufacture of bearings for internal combustion engines, but without being restricted to this use "because it is quite obvious can also be used for many other purposes can.

The casting of aluminum / tin blocks and their Processing into bearing plates and strips is e.g. in the Australian patent specification 249 218 of the company Repco described. The use of lead instead of tin in such an alloy is for example in the Australian Act 295 322 of the Pa. Eepco described.

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BATH ORIGINAL

It is well known that lead is much cheaper than tin and that aluminum / lead bearings have runnability that is equivalent to or better than the runnability of aluminum / tin bearings. However, up to now it has not been considered possible to produce a satisfactory aluminum / lead block with a relatively high lead content for these purposes. To date, usually, the lead content of Alurainium / moving lead blocks in the Hähe of 8 wt .-? 6 _f and was not in fform a continuous network, but in Kngelform before.

Lead is very poorly soluble in aluminum and only sparingly soluble in liquids. For example, aluminum dissolves at a temperature of 1000 ° C not more than 12% by weight of lead and at a temperature of 850 ° C only 7 ft. By weight of lead. Even if an aluminum / lead block is included If the above-mentioned relatively high temperatures are poured, segregations of the relatively low lead content are formed before the aluminum solidifies, the lead forming spherical segregations.

It is an object of the invention to provide an improved aluminum / lead block or other body which has a significantly increased lead content, the lead being present within the aluminum in the form of an essentially continuous network.

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Another object of the invention is to provide a method for producing an aluminum / lead block or other bodies with a relatively high lead content.

Another object of the invention is to provide an apparatus for carrying out the method for producing an aluminum / lead block or other body, _v

An aluminum / lead block or the like according to the invention is characterized in that the lead content as a whole Block uniformly in the form of a substantially continuous Metzwerkes is distributed.

The aluminum / lead block according to the invention or the like. is produced by the following process steps from an aluminum / tin block or the like, which

has a sufficiently high tin content to ensure that the tin is present in ΙΌπη an essentially continuous network *.

Arrange the aluminum / tin block in such a way that; let at least one of its surfaces is in contact with a lead bath;

Heat the aluminum / tin ingot to a temperature equal to or higher than the melting point of tin, but below the melting point of Aluminum lies so that the tin network melted and- the molten tin dissolves a percentage of the aluminum that is dependent on the temperature reached, and

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Removal of the tin-enriched liquid from the essentially continuous network in aluminum, being replaced by lead from the lead bath will.

To carry out the method is according to the invention a device is provided which is characterized by a container which has an open bottom and a circumferential Has side wall, and through liittel for producing a legible, tight connection between the open Bottom of the container and a free area of the aluminum / tin block or other body, whereby the container either a tin-enriched liquid coming from the block or an amount of lead that absorbs to replace the liquid enriched with tin in, block or other body.

In the drawing, the several examples the connection shows is:

Pig. 1 is a vertical section through an open top

Container attached to the top of an aluminum / tin socket that is immersed in a lead bath is immersed;

I ¹ Ig. 2 shows a section similar to FIG. 1 through another arrangement using two containers, the upper container containing a predetermined small amount of molten lead and the aluminum / tin block together with a lower container in a neutral one

Salt bath is immersed, and 309826/0942

Pig. 3 shows a similar step through a further embodiment example with two containers, wherein the upper container is provided with means to speed up the process and its Show end »

In the case of the S ¹ Ig. Is illustrated embodiment of the invention 1 an open-top container 2 by suitable means, such "as brackets or tie rods 3, detachably secured to the top of an aluminum / tin block 4, the block 4 has a tin content of at least 7 wt # and the tin is distributed essentially uniformly in the form of an essentially continuous network in the aluminum.

The container 2 is open at the top and bottom in this embodiment and has an upright, circumferential side wall 6 with a beveled sharp lower edge 7, which in the top of the block 4 something has penetrated and thus ensures a seal.

The aluminum / tin block 4 and the container 2 are so immersed in a lead bath 8 that the top 9 of the block 4 is substantially parallel to the surface 11 of the Lead bath and below it lies

The temperature of the lead bath (the melting point of lead is 327 ⁰ O) should be below the melting point of aluminum (66O ⁰ G). A maximum temperature of 56o ⁰ G is satisfactory, although slightly higher temperatures can be used with caution,

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It has been found that during the rise of the Temperature of the aluminum / tin block a the tin network melts in the block and depending on the maximum he " ranged temperature a certain percentage dee Dissolves aluminum. The liquid enriched with tin is pushed out of the network in the aluminum block by the molten lead of the lead bath. The flowing in So lead fills the network that originally occupied the tin-enriched liquid "

The time required for this replacement of the tin with the lead depends on the temperature and the immersion depth of the block in the lead bath. The greater the height of the side wall 6 of the container in the lead bath in fig. I. i3t, the greater the height difference between the lead bath surface and the block, and the greater it is the ambient pressure deo lead on the block, the The rate at which the tin-enriched liquid is replaced by the lead depends on the height of the lead Pressure is affected.

When the replacement process is finished, the block and the container 2 sitting on it are removed from the lead bath θ raised. Before the container is separated from the block and the latter is allowed to cool, the liquid poured out in the container above the block. Palis from one such block z. B. bearings for internal combustion engines are to be produced, the block is for example

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brought to the appropriate thickness by means of rollers before being connected to a steel support strip and by means of Cutting and processing brought into the desired shape will.

In the embodiment according to FIG. 2, the tin located in the aluminum block is replaced against Lead in the opposite direction. Bs two containers 14 and 14 are used, the container 2 with the top of the block 4 is tightly connected, while the container 14 is closed at the bottom and with the bottom of the block is tightly connected. The two containers can be connected to one another by tie rods 3. The lower container 14 is via a line 15 either on suitable ! • air vented or connected to a vacuum source, by means of which the air pressure prevailing in it falls below the ambient air pressure can be lowered *

A predetermined amount of molten lead 12 is then poured into the container 2 so that it is on top of the block 4 a lead bath is formed, the block being wholly or partly in molten neutral salt 13 is immersed.

While the tin in block 4 melts, it dissolves depending on the maximum temperature reached "certain percentage of dt-s aluminum, so that one with Tin-enriched liquid is created. Under the hydrostatic pressure of the lead 12, the liquid is out

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pressed into the network and this filled with lead.

In this embodiment, too, depends on the Exchange dea Zinna with the lead time of the used temperature and the difference sswlachen dem on the lead-covered top of the block and the pressure in the lower container 14. The exchange The tin-enriched liquid against lead is naturally accelerated when the pressure in the lower container 14 lowered under atmospheric pressure will.

In Pig. 3, other devices are used to replace the Pinnacle in the Alurainiumfclock to accelerate against lead.

For example, the container 2 attached to the top of the block 4 is provided with an upper closure 16 which has an outlet opening 17 through which the container ? can be releasably connected to a l'uiaue 18 or other suitable vacuum source. With this arrangement, however, the pressure prevailing in block 4 can be lowered rapidly to below atmospheric pressure. If so desired, the block 4 can also pass by a second container 14e, which is attached to the underside of the blocka, so that the heat exchange of lead bath in which the block and the lower container are immersed, to raise the block.

309826/0942

ORIGINAL

Means can also be provided to warn the worker by means of an acoustic or optical signal when a certain amount of lead has replaced the corresponding amount of liquid enriched with tin.
For this purpose, a manually adjustable probe 21 can be provided, which is electrically connected via a battery 23, a lamp 22 or an acoustic signal device and a return line 24, for example to the upper container 2, which is made of metal in it
is.

The probe 21 is preferably mounted in a substantially vertical socket 26 which is electrically insulated from the container 2. The lower end of the probe 21, which can be pointed, can be towards the top of the block
and be moved away from this »

Since the upper container 2 shown in Fig. 3 with
an upper closure 16 is provided, undesired oxidation of the block and the tin squeezed out of it is either completely prevented or reduced to a minimum, so that the subsequent reuse of the tin and other metals is facilitated.

In the original aluminum / tin block 4 or
Bodies can also contain additional, known alloy components, such as copper or silicone, for example. Some of these additional alloy components
can, if they are dissolved in the tin network, facilitate the replacement of the tin with lead "

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BADORiGINAL

- ίο -

A small percentage of tin, e.g. B. 5 $ of the lead, can be added to increase the corrosion resistance. This is particularly desirable if the aluminum / lead block is to be processed into bearings later.

In one embodiment, a cast is used Aluminum / tin block used. This block has 10 Wt .- $ tin and 1 wt .- $ 6 copper. The rest is aluminum. The two main faces of the blook, in this case the The top and bottom are preferably smoothed by machining and aligned parallel to each other, if this state was not reached during casting.

The containers are preferably made of stainless steel. If according to fig. I used an open container a thin layer is preferably melted initially Lead or some other suitable substance is poured onto the top of the block to keep during the To prevent the tin from being thawed out by the lead from oxidizing this surface.

It has been found that when an aluminum / tin block with a thickness of about 30 mm is immersed in a lead bath at a temperature of 550 to 56O ⁰ C, a vacuum of about 600 Torr in the upper container 2 prevails, after about ten minutes a layer of about 8 mm thick containing the tin-enriched phaoe and lead forms on the upper side of the block.

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. ■ ■ - η -

Bach can terminate this exchange of the block be raised a little so that its underside is just slightly above the surface of the lead bath. If the If negative pressure is maintained in the upper container, the lead in the network of the block will move on upwards so that a predetermined portion at the bottom of the block is lead-free. This will facilitate the later attachment of the stock material rolled from the block on a Steel plate or other base with the help of known workshop methods is much easier.

As can be seen from Fig. 3, the lower container 14a is open at the bottom and, if desired, with a plurality of Schiitzen 26 ^ or other openings provided to the To facilitate contact of the block 4 with the lead bath 8 and to prevent gas bubbles from being caught in the lower container 14a. The lower container continues to conduct heat from the lead bath to the block after the block has hit the above I was lifted out of the lead bath. The electrically isolated probe 21 can be used to measure the height of the Measure the molten metal 19 across the top of the block to determine which part of the network in the lower part of the block has been freed from lead under the influence of the pump.

The inventive aluminum / lead product has proven to be particularly advantageous because it has a has a relatively high lead content, which is distributed substantially uniformly in the aluminum block

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Alurrtinium / lead bearings according to the present Invention have extremely satisfactory properties. Of course, the area of application is limited of the invention not only on such bearings, because aluminum / lead products manufactured according to the invention are suitable for a variety of other uses. ,

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Claims (1)

Claims 1, aluminum / oil block or the like, characterized in that that the lead content in the whole block (4) is uniform is distributed in the form of a substantially continuous network. 2, aluminum / lead block or the like, characterized in that that the lead content in the whole block (4) is uniform in IPorrn of an essentially continuous one Network is distributed «, this -he block of a Aluminum / tin block was obtained, which contains an essentially continuous tin network, which through Lead was squeezed out and replaced so that the lead occupies the network originally filled with tin, 3 «aluminum / lead block or the like according to claim 1 or 2, characterized in that the lead content in the Range between 10 and 60 wt .- $, ' 4. aluminum / lead block od. The like. According to one of claims 1 to 3, characterized in that a portion of the network in the Mhe one of the main surfaces of the block is substantially free of lead to the connection between a strip made from the block or the like.. od with a steel backing plate to facilitate the like _e. 309826/0942 5. Process for the production of an aluminum / steel Blocks or: 1ς1. from an aluminum / sense block or the like » with a sufficiently high tin content to ensure, that the tin is in the form of an essentially continuous network, characterized by the following procedural steps ι Arrange the aluminum / tin block in such a way that at least one of its surfaces in contact with a lead bath; Heating the aluminum / tin block to a temperature that is equal to or higher than the melting point of the tin, but below the melting point of the aluminum, so that the tin network is melted and the molten tin a percentage dependent on the temperature reached of the aluminum dissolves, and
Removing the tin-enriched liquid from the substantially continuous network in the aluminum, replacing it with lead from the lead bath. 6. The method according to claim 5, characterized in that the removal of the tin from the substantially continuous network is effected by a pressure difference between the surface of the block (4) in contact with the lead bath and at least one other surface of the aluminum / tin block will. 309826/0942 7 »Process for making an aluminum / lead. Blocks "od _# · the like from an aluminum / zinn' block od" like ,, whose Mindestzinngehalt about 7 wt .- ^ "is to ensure that the tin is present in the form of a substantially continuous network, characterized by following procedural step fastening a container (2) on the top (9) of the aluminum / tin blook, the container being open at the bottom and having a circumferential side wall (6) that rests tightly on the block? Immersing the aluminum / tin block and part of the Container (2) in a lead bath (8), which heats the block to a temperature * which is equal to the melting point of lead is or above but below the melting point of aluminum, making the tin network melts and one of the maximum temperature reached dependent. Percentage of aluminum dissolves, which a tin-enriched liquid is formed by the hydrostatic pressure of the lead bath is printed out of the block and flows up into the container, with the former from the with Tin-enriched liquid ingested in the aluminum network now with lead from the lead bath is filled. 309826/0942 8. Device for performing the method according to one of claims 5 to 71, characterized by a Container (2), the one open bottom and one circumferential Has side wall (6), and zwieohen by means for producing a releasable, tight connection open bottom of the container (2) and a free surface of the aluminum / tin blook (4) or other body, wherein the container (2) either a tin-enriched liquid originating from the block B or a quantity of lead which is intended to replace the tin-enriched fluid in the block or other body 9β aluminum / lead blook or other product, characterized in that the lead is in the form of a substantially continuous network. 309826 / Ü942