FIELD OF INVENTION:

The present disclosure relates to a method of production of alloys. More specifically, the invention relates to casting of alloys to achieve a uniform dimension.

BACKGROUND

The present invention relates generally to the casting of metal alloys and more specifically, to the casting of ferroalloys. In recent years, commercial users of ferroalloys ( foundries )have increasingly specified that these products be supplied in relatively uniform cross-section which is lower than 1 mm. Therefore, in the conventional manufacture of ferro-alloys, it has been common practice to use the open die casting process to cast these alloys having gross dimensions of approximately _10-30mm. However, this process does not result in the alloys with desired uniform cross sections and in order to achieve the same, secondary operations would be performed by subjecting the casts to numerous round of crushing and sizing. Though this would result in the desired size, the proportion of unusable product which was being generated is high and has to be subject to re melting and subject to the entire process of casting again. Also, this process increases the time and is not efficient economically. Hence there is a need for a better process for the manufacture of ferro alloys which will yield casts with lower cross sections so that the desired engineering properties can be achieved, where the range of consistency will be in a narrower band, thus increasing the process effectiveness. OBJECT OF THE INVENTION

The object of the invention is to provide a process for producing/ casting of the metal alloys in a predefined dimension with uniform cross-section.

SUMMARY

This summary is provided to introduce a selection of concepts, in a simple manner, which are further described in detailed description of the invention. This summary is neither intended to identify the key or essential inventive concept of the subject matter, nor to determine the scope of the invention.

The object of the invention is achieved by a method of casting a metal alloy according to claim

1. A method for casting metal alloys is disclosed, which includes step of pouring the molten metal alloy into a rotatable die and rotating the die at a first predefined speed for spreading the molten metal alloy uniformly on the wall of the die, and cooling down the molten metal alloy. The time period for pouring the molten metal alloy into the rotatable die, and further cooling the molten metal alloy while it is being rotated is less than 10 minutes.

According to another embodiment of the method, after cooling of the metal alloy, rotating the rotatable die to a predefined time period at a second predefined speed for breaking down the cooled metal alloy. According to yet another embodiment of the method, wherein the metal alloy is a ferrosilicon alloy. According to one embodiment of the method, wherein the metal alloy is casted with the thickness in the range of 10 mm to 15 mm.

According to another embodiment of the method, wherein the metal alloy is casted with the thickness in the range of 15 mm to 25 mm.

According to yet another embodiment of the method, the method further includes steps of heating the metal alloy in a Submerged Arc furnace or Induction furnace, and adding Magnesium using a ladle into the molten metal. According to one embodiment of the method, the method further includes step of crushing and/or sizing the cooled down metal into a predefined thickness, and a longitudinal dimension in a range of 5 mm to 10 mm.

According to another embodiment of the method, wherein the first predefined speed of rotation of the rotatable die is in the range of 350 RPM to 500 RPM.

According to yet another embodiment of the method, wherein the rotatable die is of a diameter in the range of 1000-1200 mm. According to one embodiment of the method, wherein the rotatable die is of a length in the range of 3000-3500 mm.

To further clarify the advantages and features of the present invention, a more particular description of the invention will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the invention and are therefore not to be considered limiting in scope. The invention will be described and explained with additional specificity and detail with the appended figures.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described and explained with additional specificity and detail with the accompanying figures in which:

Figure 1 illustrates the process flowchart of the casting of the alloys according to an embodiment of the invention.

Figure 2 illustrates an image from scanning electron microscopy from a sample of metal alloy casted through open slab casting.

Figure 3 illustrates an image from scanning electron microscopy from a sample of metal alloy casted centrifugally. Figure 4 illustrates the casting properties of the metal alloy casted through open mould production and the centrifugal casting method.

Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, the figures may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein. DETAILED DESCRIPTION OF INVENTION

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as would normally occur to those skilled in the art are to be construed as being within the scope of the present invention.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more sub-systems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other , sub-systems, elements, structures, components, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.

Embodiments of the present invention will be described below in detail with reference to the accompanying figure.

Figure 1 illustrates the process of casting of the metal alloys. The metal alloy is firstly molted in one of the submerged Arc furnace or Induction furnace. Thereafter through a ladle, an additive is added into the molten metal alloy. Further, the molten metal alloy is poured into a centrifugally rotating device which is rotating at a first predefined speed. The device has a rotatable die, and the molten metal alloy is poured onto the rotatable die while the die is rotating. Due to the rotational force, the molten metal alloy is pushed towards the wall of the rotatable die. The total time period from pouring the molten metal alloy onto the rotatable die and further cooling down of the metal alloy is less than ten minutes. Once the metal is cooled down, it is further crushed and sized into a predefined dimension. When the alloy is in the desired shape, it is packed, and made ready for the shipping.

In one embodiment, the first predefined speed of rotation for rotating the rotatable die is kept in a range of 350 RPM to 500 RPM.

In one embodiment, the rotatable die is of a diameter in a range of 1000 mm to 1200 mm. In another embodiment, the rotatable die is of a length in a range of 3000 mm to 3500 mm. In one embodiment, only one of the sizing or crushing operations takes place to achieve the predefined dimensions. In another embodiment, the pre-casting process of melting alloys can be carried in any other suitable furnace, and it need not be either the Submerged Arc furnace or the Induction furnace. In yet another embodiment, the additives may not be added. In one embodiment, the metal alloy used is Ferrosilicon. It is to be noted that the methodology for centrifugal casting is applicable to any other type of metal alloys too.

In one embodiment, the additive is Magnesium. However, it is pertinent to note that any other additive which is suitable to a metal alloy can be used in the centrifugal casting method.

In one embodiment, the rotatable device in which the rotatable die is placed has 3000-3500mm, and entire machine dimensions are of 12000 mm length. In a particular embodiment, the metal alloy casted through the method shall be having the width between 10 mm to 15 mm. Alternatively, in another embodiment, the metal alloy casted shall be having a width in range of 15 mm to 25 mm. It is to be pertinent to be noted that the method of the invention is used to produce the cast of uniform thickness, i.e., if the chosen thickness for production is 10 mm, than all the metal pieces casted shall be having the same uniform thickness. To change thickness width of the metal alloy to be produces, one or more production parameters are changed, such as a predefined speed of rotation of the rotatable die, dimension of the rotatable die used, the dimensions of the rotatable device in which the rotatable die is placed, the molten metal temperature before pouring into the rotatable die, the predefined time period of rotation. Please note that accordingly for different molten alloy to be casted, such above-said parameters may again require to be changed for achieving a predefined dimension.

In one embodiment, the longitudinal dimension of the metal alloy is kept in a range of 5 mm to 10 mm, and same can be carried out by doing sizing and/or crushing operations.

In one embodiment, after cooling down of the metal inside the rotatable die, the rotatable die is further continued to be rotated at a second predefined speed, and a predefined time period. This second predefined speed and the predefined time period is variable according to the metal alloy being casted. In a preferred embodiment, the second predefined speed is kept within 100 RPM. In another preferred embodiment, the predefined time period for rotation to break down the cooled metal alloy shall be within five minutes. It is to be noted that by varying the parameters of the centrifugal casting process namely speed the thickness can be varied.

Also, the metal is spread and fill up by the centrifugal action along with fluidity as compared to just fluidity in case of the open mould process.

This ensures uniform filling and hence uniform microstructure which is important to determine the action of the alloy during the foundry operations of Magnesium alloy treatment or Inoculation as the case may be.

The microstructure of the product cast between these two different processes are comparable and the same analysis has been done using a Scanning electron Microscope which reveals the fineness of the grain structure ( provides better dissolution and action) when added to the Foundry operations. This is shown through the images from Scanning electron Microscope of the Figure 2 and Figure 3. Figure 2 shows image from scanning electron microscopy from a sample of metal alloy casted through open slab casting. Figure 3 shows the image from scanning electron microscopy from a sample of metal alloy casted centrifugally. The different is clearly visible in the microstructure of the centrifugally casted sample of the metal alloy which is finer with uniformity with respect to the sample which is casted in open mould.

The casting properties are further illustrated through the table shown in Figure 4. The table shows the properties of the samples which are casted through the open mould process, and through the centrifugal casting method. One observation of the test was that the Magnesium percentage in the centrifugal casted metal alloy was lower with respect to the open mould one. Another observation of test was that the performance of both the samples were similar.

The main criteria to be considered while designing the centrifugal casting die for a metal alloy is its fluidity and volume of metal.

Based on the pouring ladle capacity and the temperature, viscosity and solidification temperature, the design of the centrifugal casting system can be varied such that the filling time, length and diameter of the die are able to fill and cool the complete poured metal within 4 minutes.

While specific language has been used to describe the invention, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.

The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.