DEP0053822DA - Copper alloys - Google Patents

Description

Tin-containing copper alloys with a tin content of up to about 20% tin are known as tin bronzes, gunmetal and special bronzes and are used in industry for a wide variety of purposes. For example, there are thrust bearings, wear plates, slide plates and bells made of cast bronze 20, that is to say of a bronze with 20% tin; Highly stressed bearing shells, wheels and hydraulic apparatus for high pressure consist of cast bronze 14, parts for general use in machine, valve and apparatus construction made of cast bronze 10, wires, sheets and strips of rolled bronze 6. The copper alloy known as gunmetal 10 with 10% tin and 4% zinc is generally used in machine, valve and apparatus construction, as well as for pipeline components. Gunmetal 9 consisting of 85% copper, 9% tin and 6% zinc is used as a bearing for railroad purposes and as a material for fittings. Gunmetal 8, 5 and 4, i.e. alloys with an addition of 3 or 1% lead, are used to make machine fittings, pipe flanges and other hard-soldered parts. Tin lead bronzes with a content of 86% copper, 10% tin and 4% lead or with a content of 80% copper, 8% tin and 12% lead are used as special bronzes for bearings in hot rolling mills, electrical machines or for bearings with high surface pressure as they occur in cold rolling mills.

Because of the tin shortage, these various fittings and device parts can no longer be manufactured to the required extent. Technology has long tried to find substitute materials that have the same properties as tin-containing bronzes and gunmetal alloys.

So far, special brasses SoMs 70 with 68 to 71% copper, (0.5 to 3.7% Al + Mn + Fe), 0.3 to 0.7% silicon, up to 0.5% nickel have been used as replacement materials for this purpose , Balance zinc for

Sheets and strips used.

The invention has set itself the task of creating materials from tin-free copper alloys, which have the high strength and hardness of cast and special bronzes, as well as gunmetal.

It is based on the assumption that the hardness and strength of alloys with copper, iron and phosphorus, which are harder and stronger than copper, can be tempered and thus increased considerably by quenching and tempering. It gives an iron-phosphorus-copper alloy containing 2.45% iron and 0.45% phosphorus, a Brinell hardness of about 67 and 70 after hot rolling and annealing, and a hardness of about 100 after cold rolling.

It is also known that iron-copper alloys with an addition of phosphorus that is higher than that required for the formation of iron phosphide (Fe (sub) 3P) can be treated with certainty. For example, with an alloy of about 0.5% iron and 0.25% phosphorus, after quenching and tempering the casting, a strength of 28 kg / sq.mm and a hardness of about 72 were obtained. However, it is not yet known that the hardness and strength of these tin-free alloys can be increased by adding suitable substances without impairing the castability.

The invention solves the problem with alloys of the following composition:

0.5 to 12% iron phosphide

0.01 to 0.15% phosphorus

0.2 to 8% of one or more of the elements silicon, manganese, zinc or aluminum

Remainder copper

Thus, substances such as silicon and / or manganese etc. are added to the known copper-iron-phosphorus alloys, which increase the strength and hardness of the starting alloy without significantly impairing its castability. These alloys are particularly suitable as casting alloys when the aim is to achieve high strength and hardness. So results in a cast alloy with

4% iron phosphide

0.5% phosphorus

8% silicon

Remainder copper

In addition to an excellent thin liquid, a hardness of 180 Brinell. The alloy is therefore eminently suitable, for example, for casting bells. The property of being quenched and tempered allows the material to be adapted to the desired conditions through the quenching and tempering treatment.

If the content of the alloy components specified above is reduced in the specified alloys, the alloys are suitable as rolled alloys. These alloys have the following composition:

0.5 to 8% iron phosphide

0 to 0.15% phosphorus

up to 7% of one or more of the elements silicon, manganese, zinc or aluminum

Remainder copper

According to a further idea of the invention, the heat treatable iron phosphide-copper alloys are also suitable as rolled alloys without the addition of hardness-increasing substances such as silicon etc. Because they can be deformed perfectly warm and then cold. The hardness can be adjusted to the desired degree of hardness by tempering after cold forming, as the following example shows:

The following alloy was produced as a replacement material for WBz 6:

4% iron phosphide

0.1% phosphorus

Remainder copper

In the as-cast state it has a Brinell hardness of 96. This alloy can be hot and cold pressed and resulted in the following hardnesses depending on the cold working:

If you want to achieve higher levels of hardness, a corresponding amount of silicon must be alloyed. This is how an alloy yielded:

4% iron phosphide

3% silicon

Remainder copper

a hardness of 120 Brinell in the cast and annealed condition.

Cold working increases the hardness roughly twice. This achieves practically all of the properties, strength and spring quality that tin bronzes WBz 6 to 9 have.

Alloys, such as those with the composition 2% iron phosphide, 0.1% phosphorus, the remainder copper, achieve a hardness of 86 Brinell even in the unannealed state. The hardness can be increased to 98 Brinell by tempering to 440 °. Like normal tin bronzes, the alloys can be tempered in roughly the same way by quenching and tempering, with Brinell increases of up to 25 units being achieved through tempering.

The hardness of the silicon-free alloys can also be increased by a further 10% by adding free phosphorus of 0.5%. The rolled alloys can also be used as coin bronze alloys.

The special bronzes for bearings are in the range of the following composition:

0.5 to 16% iron phosphide

0.2 to 8% silicon

0.5 to 12% lead

0.01 to 0.5% phosphorus

Remainder copper

Example: 5% iron phosphide, 2.5% lead, 0.3% phosphorus, the remainder copper, as bearings for electrical machines.

The alloys can easily be produced in suitable melting furnaces. The best way to add iron phosphide is to use appropriate alloys of a balanced iron-phosphorus powder mixture. The melts can be poured easily and cleanly because they are very thin.

So you can create strong wire bars (100 mm) for the hot wire rolling mill in normal or cooling molds or, even better, cast in the continuous casting process. In the rolling mill, the wire bars are at temperatures of 800 to 950 °, primarily at

870 °, rolled directly to 6 mm. The alloys can also be processed warm on the extrusion press to produce bars and profiles, e.g. for the production of bearing shells.

The corrosion resistance of the silicon-free alloys is almost as great as the corrosion resistance of the WBz 6 bronze. The silicon-containing alloys show an even higher resistance to acids.

These alloys, especially rolled alloys, offer the following advantages over the tin-containing bronze alloys of DIN sheet 1705:

1. The tin-free alloys are very inexpensive.

2. The rolled alloys can be processed (the alloys containing tin do not allow hot working).

3. The structure of the alloys and the heat treatment properties are practically identical to those of tin bronzes, so that top values for the spring qualities can also be achieved by means of heat treatment.

4. In the case of tin alloys, the waste must be stored separately according to its composition so that subsequent reprocessing can be carried out profitably. The residues of the tin-free alloys can easily be converted back into the purest copper by melting them down in the refining furnace. There is no separation of the individual types.

5. The wrought alloys are particularly suitable for replacing phosphor bronze weaving wires, antenna wires, sieve wires, springs, gong sticks, axes for water knives, push button springs, glasses rods and insert springs, brush wires, bandages, metal hoses, switch springs, etc.

Claims (6)

1. Copper alloys, especially cast alloys, characterized by the following composition: 0.5 to 12% iron phosphide 0.01 to 0.15% phosphorus 0.2 to 8% of one or more of the elements silicon, manganese, zinc or aluminum Remainder copper 2. Copper alloy according to claim 1, in particular for bell casting, characterized by the following composition: 4% iron phosphide 0.01 to 0.5% phosphorus 0.2 to 8% of one or more of the elements silicon, manganese, zinc or aluminum Remainder copper 3. Copper alloys according to claim 1, in particular rolled alloys, characterized by the following composition: 0.5 to 8% iron phosphide 0.01 to 0.15% phosphorus 0.2 to 8% silicon Remainder copper 4. Copper alloys, especially for bearings, characterized by the following composition: 0.5 to 16% iron phosphide 0.2 to 8% silicon 0.5 to 12% lead 0.01 to 0.5% phosphorus Remainder copper 5. Use of workpieces made of alloys according to claim 1 to 4, which are optionally hot and cold deformed and then tempered, made of substitute materials for tin-containing copper alloys. 6. Use of alloys 0.2 to 8% silicon 0.5 to 8% iron phosphide 0.01 to 0.15% phosphorus Remainder copper as a material for the production of hot and cold formed workpieces.