DESC:PRIORITY STATEMENT
The present application hereby claims priority from Indian patent application with the application number 202341024814, filed on 31 March 2023, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD OF INVENTION
The present invention relates to a method for recycling maraging steel scrap. More particularly, the invention relates to a process of melting the maraging steel scrap in an electric arc furnace, conditioning the electrode, and remelting the electrode in an Electroslag refining furnace to produce a refined ingot.

BACKGROUND OF INVENTION
Maraging steel is a specialized steel alloy known for its excellent strength and durability. It represents a class of steel alloy distinguished by their remarkable properties, notably their capacity to form martensite without the necessity for quenching and their ability to demonstrate age-hardening characteristics. T Maraging steel have garnered significant attention as viable alternatives to traditional quenched and tempered steels, particularly within high-performance sectors such as aerospace, among others.
Maraging steel has a very high tensile strength of around 2000 MPa, and is excellent in workability and weldability. A typical composition of the maraging steel contains 18% Ni, 8% Co, 5% Mo, 0.4% Ti, 0.1% Al and the balance of Fe.
The maraging steel contains appropriate amounts of Co, Mo and Ti as hardening elements, and can obtain high strength by precipitating intermetallic compounds such as Ni3Mo, Ni3Ti or Fe2Mo through aging treatment.
These steels are generally produced by the combination of vacuum induction melting (VIM) and vacuum arc remelting (VAR) processes. The production of maraging steel involves melting of raw materials, which generates significant amounts of scrap material during the manufacturing process. Recycling of this scrap material is essential to reduce waste and conserve resources.
For example, as disclosed in Japanese Patent Application 2003-221614 (see Patent Document 1), in which vacuum arc remelting is applied using a low nitrogen melting raw material, an expensive and carefully selected melting raw material is used. Since it is manufactured by remelting, maraging steel is currently an extremely expensive material.
To achieve cost-effective manufacturing of maraging steel, there exists a method aimed at reducing Cobalt (Co) and Titanium (Ti). However, this approach often compromises the high-strength properties inherent to maraging steel. Furthermore, even when utilizing scrap materials comprised of maraging steel as raw materials, challenges arise, particularly in processes such as vacuum induction melting. Maraging steel inherently contains nitride or oxide-forming elements like Ti or Al, leading to the presence of undesirable inclusions. It becomes imperative to meticulously clean the outer surface of scrap materials to prevent the generation of these inclusions. Additionally, the utilization of a vacuum induction melting furnace poses shape restrictions on the raw material, necessitating operations such as shape selection and cutting processing. Consequently, some scrap materials may not be effectively repurposed.
Currently, there are limited methods for recycling maraging steel scrap, and many of these methods are not efficient or cost-effective.
With this background, the present invention discloses a novel melting route for production of high purity maraging steel scrap efficiently as well as economically.

OBJECT OF THE INVENTION
The object of the present invention is to provide a novel and efficient method for recycling huge quantities of maraging steel scrap, while maintaining the quality and purity of the resulting ingots.
Another object of the present invention is to disclose a melting process route wherein upto 80% maraging steel scrap content can be added to manufacture variety of aerospace products with stringent Ultrasonic Testing quality and mechanical property requirement.

SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the disclosure. This summary is neither intended to identify key or essential inventive concepts of the disclosure nor is it intended for determining the scope of the disclosure.
The present invention discloses a method of recycling maraging steel scrap into high purity maraging steel ingots, the method comprising melting maraging steel scrap in an electric arc furnace (EAR) at a temperature range of 1500 – 1700 degrees Celsius; forming an electrode from the molten scrap, assigning Parent Heat Number to the electrode; remelting the said electrode in an Electroslag Refining Furnace (ESR) at a temperature range of 1500-2000 degrees Celsius to produce a refined ingot.

DETAILED DESCRIPTION OF THE INVENTION
MDN 250 or Maraging 250 is a type of ultra-high strength steel that is known for its excellent strength-to-weight ratio, toughness, and resistance to corrosion. It is made primarily from iron, nickel, and cobalt, with small amounts of other metals such as titanium and aluminum.
The term "maraging" comes from the words "martensitic" and "aging," which refer to the process by which the steel is produced. Maraging 250 is created by heating and cooling the steel in a way that creates a martensitic structure, which is then further strengthened by a process called aging.
Maraging 250 is commonly used in aerospace, defense, and other high-performance applications where strength and durability are critical. It is used to make components such as rocket motor casings, high-stress aircraft parts, and tooling for metalworking and plastic molding.
Overall, Maraging 250 is a highly specialized and advanced material that offers exceptional strength and performance properties.
The present invention discloses MDN 250 having composition in weight percent as follows: Ni – 18%, Co – 8%, Mb – 5%, Ti – 0.5%, Al – 0.1% and Fe – Balance along with inevitable impurities.
The present invention provides a novel method for recycling maraging steel scrap wherein the scrap material is obtained from melt shop, forge scrap, and machine scrap metallurgical having a single chemistry.
The present invention includes Melting of Maraging Steel Scrap in an Electric Arc Furnace. The maraging steel scrap is melted in an electric arc furnace at a temperature range of 1500 – 1700 degree Celsius. The resultant molten scrap is checked for chemistry, and the chemistry is adjusted accordingly.
The next stage involves forming of the electrode. In this stage, an electrode is formed from the molten scrap. The electrode is given a unique identification number as the Parent Heat Number. The electrode is then conditioned by removing the oxide scales and grinding it. The electrode is then stored for future use.
In accordance with an embodiment of the present invention, the Electrode is further remelted in an Electroslag Refining Furnace at a temperature range of 1500-2000 degree Celsius. This remelting process refines the electrode and produces a refined ingot.
In accordance with an embodiment of the present invention, the Chemistry of the Final Ingot is checked and tested for impurities and trace elements using Gas checking.
In accordance with an embodiment, the present invention provides a method for recycling maraging steel scrap that is efficient and cost-effective. By melting the scrap in an electric arc furnace and remelting the electrode in an Electroslag refining furnace, the resulting refined ingot is of high quality and can be used in various high-performance applications.
In accordance with an embodiment of the present invention, scrap content upto 80% can be added to manufacture variety of aerospace products with stringent Ultrasonic Testing quality and mechanical property requirement.

ADVANTAGES AND APPLICATION

The present invention provides several advantages over existing methods for recycling maraging steel scrap. By using a combination of electric arc furnace and electroslag refining furnace, the method produces high-quality ingots with desired chemistry and purity, while minimizing the loss of quality and increasing impurities. The method is also cost-effective and efficient, making it ideal for large-scale recycling operations.
,CLAIMS:CLAIMS
We claim
1. A method of recycling maraging steel scrap into high purity maraging steel ingots, the method comprising:
a. Melting maraging steel scrap in an electric arc furnace (EAR) at a temperature range of 1500 – 1700 degrees Celsius;
b. Forming an electrode from the molten scrap, assigning Parent Heat Number to the electrode;
c. Remelting the said electrode in an Electroslag Refining Furnace (ESR) at a temperature range of 1500-2000 degrees Celsius to produce a refined ingot.
2. A method of recycling maraging steel scrap as claimed in claim 1, wherein the chemistry of the molten scrap is adjusted prior to forming the electrode.
3. A method of recycling maraging steel scrap as claimed in claim 1, wherein the Parent Heat Number is the Unique Identification Number allocated to each electrode.
4. A method of recycling maraging steel scrap as claimed in claim 1, wherein the electrode is conditioned by removing the oxide scales.
5. A method of recycling maraging steel scrap as claimed in claim 1, wherein the refined electrode is stored in a controlled environment to prevent further oxidation.
6. A method of recycling maraging steel scrap as claimed in claim 1, wherein the electrode is remelted multiple times in the Electroslag Refining Furnace to achieve desired refinement.
7. A method of recycling maraging steel scrap as claimed in claim 1, wherein the refined ingot is tested for its chemistry and impurities.
8. A method of recycling maraging steel scrap as claimed in claim 1, wherein the final ingot is subjected to heat treatment processes to enhance its mechanical properties.
9. A method of recycling maraging steel scrap as claimed in claim 1, wherein the scrap content of up to 80% is added to manufacture various aerospace products with stringent Ultrasonic Testing quality and mechanical property requirements.
10. A method of recycling maraging steel scrap as claimed in claim 1, wherein the method involves a combination of electric arc furnace and electroslag refining furnace to produce high-quality ingots with desired chemistry and purity.