GB2038364A

GB2038364A - Alloying Additive

Info

Publication number: GB2038364A
Application number: GB7847385A
Authority: GB
Original assignee: SOLMET ALLOYS
Current assignee: SOLMET ALLOYS
Priority date: 1978-12-06
Filing date: 1978-12-06
Publication date: 1980-07-23
Also published as: NO793958L; DE2949103A1; GB2038364B

Abstract

An alloying additive for producing alloys of non-ferrous metals comprises particles of one or more alloying elements at least substantially surrounded by a mixture of one or more fluxes, and a diluted oil, preferably a mixture of a vegetable oil and kerosene. The metal base is preferably Al, Mg, Cu, Zn or Pb, and the additive one or more of Fe, Mu, Cr, Ni, Ti, Zr, B, Cu, Si, Pb, Bi and Cd; the preferred fluxes being chlorides and fluorides of Na, K, Mg, Ca, Mn. The additive may be introduced in a paper bag or metal container.

Description

SPECIFICATION An Alloying Additive for Producing Alloys of Non-ferrous Metals and a Method of Producing Such an Additive This invention relates to an alloying additive for producing alloys of non-ferrous metals and to a method of producing such an alloying additive.

In producing metal alloys, alloying elements are added to the molten metal, which forms the base of the alloy, often referred to as the metal base. Problems however qccur in producing alloys of non-ferrous metals because the alloying elements usually have a much higher melting point than the metal with which they are to be alloyed and furthermore the alloying elements are often easily oxidisable, a film of oxide being created on the exterior of the alloying elements thus slowing down or even preventing the alloying from taking place.

The usual method of dealing with this problem is to add to the metal base, not the alloying element as such, but ingots of so-called hardener or master alloy. These hardener or master alloy ingots are constituted by the alloying elements alloyed in a relatively high percentage with the metal which forms the metal base of the alloy to be produced. These ingots have to be specially produced and are relatively expensive because of the amount of metal base which has to be included and the necessity for using very high temperatures in order to melt the alloying elenents so as to produce the hardener or master alloys. Thus, the hardener or master alloy is "diluted" when the hardener or master alloy is inserted into the molten metal base.In order to ensure that the ingot of hardener or master alloy is immersed in the molten metal base, it can be dropped in so that any crust or slag which is formed on the surface of the metal base is penetrated. If necessary, the molten metal base can be agitated so as to assist in the distribution of the material of the ingot until the ingot has fully melted and blended in with the metal base.

The present invention seeks to provide an alloying additive for producing alloys of nonferrous metal in which the oxidation of the alloying elements is reduced substantially to zero and which provides an additive which is relatively inexpensive to produce as compared to hardener or master alloys.

According to a first aspect of the invention, there is provided an alloying additive for producing alloys of non-ferrous metals comprising bne or more alloying elements in particulate form, wherein each particle is at least substantially surrounded by a mixture of one or more fluxes and å diluted oil.

The oil may be vegetable oil and this oil may be diluted with paraffin.

Preferably the fluxes are chlorides or fluorides of one or more of potassium, sodium, magnesium, calcium or manganese.

Preferably the particles of the alloying element(s) are smaller than 4 inch, the majority of the particles lying desirably in the range of 1/8 inch to 200 mesh (Bss). Suitable alloying elements include manganese, iron, chromium, nickel, titanium, boron, copper, silicon, lead, bismuth, cadmium and zirconium. Cryolite may be used as the flux or one of the fluxes.

According to a second aspect of the invention, there is provided an alloying additive wherein the fluxes include one or more of the Chlorides of Potassium, Sodium and Magnesium.

If necessary, one or more of the alloying elements may be ground to a suitable size during mixing. The particles of the one or more alloying elements, the particles of the flux and the amounts of diluted oil may be mixed together in a grinding mill whereby the alloying elements and flux are ground at the same time as they are mixed.

The invention will now be described in greater detail by way of example, with reference to the drawings in which: Figure 1 is a view of a paper sack of alloying additive according to the invention, partially cut away, and Figure 2 is an enlarged view of the circle labelled II in Figure 1.

Referring to the drawings, Figure 1 shows a paper sack 1 of one form of alloying additive in accordance with the invention, and as can be seen from the broken away portion 2, it consists of a large number of particles 3 of one or more alloying elements each effectively covered by a mixture of one or more fluxes and vegetable oil and paraffin.

Figure 2 shows an enlarged part of the section of Figure 1 as indicated at II and from this can be seen the individual particles 3 which are substantially surrounded by the flux, oil and paraffin mixture 4.

The effect of this construction is to provide the particles of the alloying element(s) with a flux mixture coating which effectively prevents oxidation of the exterior surfaces of the particles and has the advantage that, when the alloying additive lumps are introduced in the molten metal base, the flux will be melted by the metal base, thus freeing the particles for intimate contact with the metal base without there being any opportunity for the particles to oxidise. The provision of the vegetable oil and paraffin which are mixed with the flux(es) act as a dust suppressant which allows the material' to be used in particulate form without the necessity of conglomerating the material into lumps. It also reduces the hygroscopic nature of the flux(es) and prevents atmospheric water pollution and destruction of the fluxing action.In the course of the alloying, the molten flux will float to the top of the melt and due to melting will distribute the particles to some extent within the molten metal base. The flux will also tend to cause a certain amount of turbulence in the molten metal itself, thus assisting in the homogeneous distribution of the alloying element(s) in the molten metal base.

The vegetable oil and paraffin will be vaporised or burnt off without any deleterious effect.

Furthermore, it will be seen that the alloying additive consists solely of the alloying element(s) together with the necessary flux mixture and does not include any of the metal of the metal base, thus rendering the cost of alloying additives less than that of the hardener or master alloy ingot necessary to produce the same alloying.

Furthermore, as will be described, the actual cost of producing the alloying additive is reduced because there is no necessity for the alloying element(s) to be heated.

One method of producing an alloying additive in accordance with the invention will now be described. In this particular case, an alloying additive of manganese for use particularly in alloying with aluminium will be referred to.

Manganese powder or flake, which is the form in which this metal is usuallly commercially available, is placed in a grinding mill, such as a ball mill or a rod mill together with fluxes in powder form and suitable quantities of vegetable oil and paraffin. Fluxes used in combination with manganese are usually potassium chloride and sodium chloride. Magnesium chloride may also be used together with these two original fluxes.

The fluxes may also be used in the form of coarse powder or lumps. After suitable amounts of the manganese and the various fluxes together with the vegetable oil and paraffin have been placed in the grinding machine, they are mixed together and ground to suitable size, by means of the grinding mill, in one stage. A suitable ratio of the manganese to the flux is 80:20 parts by weight but this can be varied between 50:50 and 95:5 parts by weight if desired. This suitably constitutes 99.5% of the alloying additive, the remaining 0.5% being made up of a 50:50 mixture of a vegetable oil, such as that sold under the brand names "Risella" or "Ondina" by the Shell group and paraffin. The powder flakes are ground in the mill until the manganese ends up in powder form with particle sizes, in the majority of between 1/8 inch to 200 mesh (in accordance with British Standards Mesh Specification).Smaller particles may be readily tolerated but no particles should exceed - inch. The flux particles are desirably from 30 mesh downwards but, the actual particle sizes of the flux is not particularly critical providing that it is small enough to provide a good coating on the metal particles. After the completion of the grinding and mixing operation, the mixture is then placed in paper sacks as shown in Figure 1 or in aluminium canisters and is ready for use.

Where paper sacks are used these will be burnt when the additive is added to the metal to be alloyed without deleterious effect. Where metal canisters are used, these must be of the same metal as the metal to be alloyed.

It will be understood that while the method described relates to the production of a manganese additive it could equally well apply to other additives suitable for use with non-ferrous metals. These additives may include one or more of manganese, iron, chromium, nickel, titanium, boron, copper, silicon, lead, bismuth, cadmium and zirconium. Furthermore various fluxes may be used; suitable fluxes include the chlorides or fluorides of potassium, sodium, magnesium, calcium and manganese. Also included are the more natural forms fluorspar and cryolite. The non-ferrous metals which may be used as metal bases for the alloys include aluminium, copper, magnesium, zinc and lead. Other suitable oils and dilutants may also be used.

It will be appreciated that it is of particular importance that the alloying materials should be heavier than the melt to which they are applied so that they sink to the bottom of the melt, having penetrated any crust or slag formed on the surface, and do not remain floating on the surface.

Different techniques are required for use with additives which are lighter than the metal base melt. Furthermore, it will be understood that not only is the additive suitable for making alloys of a specific metal base but also for varying the constituents of an already existing alloy by the addition of additional alloying elements or by varying the percentage ratio of the elements already present in the alloy. The number of alloying elements that may be used in a single solid additive can be varied depending upon the alloy to be produced with them. Alternatively the alloying additives may be restricted to a single alloying element and different types of additive may be used when more than one alloying element is to be added. Where the fluxes are concerned, it is usual to use two or three different fluxes, but any suitable number may be used.

In the operation of alloying the metal base with the alloying element(s) in the alloying additive as previously described in the above embodiment, all that is necessary is to know the amount of the melt, whereupon the weight of the additive material can be determined knowing the relative weight of the alloying elements and the flux.

Actual weighing is not generally necessary since the alloying additive is supplied in preweighed amounts.

From the above it will be seen that the invention makes possible the provision of an alloying additive which is adequately protected against oxidation and to a substantial degree against the action of water or water vapour which is readily dispersed in a melt and which is of reduced cost due to ease of production and due to the lack of any metal base metal necessary, except where the additive is supplied in metal canisters.

Claims

1. An alloying additive for producing alloys 6f non-ferrous metals comprising one or more alloying elements in particulate form, wherein each particle is at least substantially surrounded by a mixture of one or more fluxes and a diluted oil.

2. An alloying additive as claimed in Claim 1, wherein the oil is vegetable oil.

3. An alloying additive as claimed in Claim 1 or 2, wherein the oil is diluted with paraffin.

4. An alloying additive as claimed in Claim 1, 2 or 3, wherein the fluxes are chlorides or fluorides of one or more of potassium, sodium, magnesium, calcium or manganese.

5. An alloying additive as claimed in any one of Claims 1 to 4, wherein the particles of the alloying element(s) are smaller than T inch.

6. An alloying additive as claimed in Claim 5, wherein the majority of the particles lie in the range 1/8 inch to 200 mesh (B.S.S.).

7. An alloying additive as claimed in any one of Claims 1 to 6, wherein the alloying elements are selected from Manganse, iron, Chromium, Nickei, Titanium, Boron, Copper, Silicon, Lead, Bismuth, Cadmium and Zirconium.

8. An alloying additive as claimed in any one of Claims 1 to 7, wherein the alloyimg element is manganese.

9. An alloying additive as claimed in any one of Claims 1 to 8, wherein at least one of the fluxes is Cryolite.

10. An alloying additive as claimed in any one of Claims 1 to 8, wherein the fluxes include one or more of the Chlorides of Potassium, Sodium and Magnesium.

11. A method of producing an alloying additive for making alloys of non-ferrous metals comprising mixing together particles of one or more alloying elements with particles of one or more fluxes and an amount of diluted oil, whereby a particulate material is formed in which the alloying element particles at least substantially surrounded by a mixture of lux(es) and diluted oil.

12. A method as claimed in Claim 11, wherein the oil is vegetable oil.

13. A method as claimed in Claim 11 or 12, wherein the oil is diluted with paraffin.

14. A method as claimed in Claim 11, 12, or 13 wherein the one or more alloying elements are ground to a suitable size during mixing.

15. A method as claimed in Claim 11, 12 or 13 wherein the particles of the one or more alloying elements, the particles of the flux and the amounts of diluted oil are mixed together in a grinding mill whereby the alloying elements and flux are ground at the same time as they are mixed.

16. An alloying additive for producing alloys of non-ferrous metals substantially as described herein with reference to the drawings.

17. A method of producing an alloying additive for making alloys of non-ferrous metals substantially as described herein with reference to the drawings.