WO2024069251A1

WO2024069251A1 - A high strength wear and corrosion resistant grey cast iron and a method of manufacturing thereof

Info

Publication number: WO2024069251A1
Application number: PCT/IB2023/055865
Authority: WO
Inventors: Shiv Varan Singh CHAUHAN; Deodatta Shende; Shripadraj Ponkshe
Original assignee: Tata Motors Limited
Priority date: 2022-09-29
Filing date: 2023-06-07
Publication date: 2024-04-04

Abstract

The present disclosure discloses a method for producing high strength wear and corrosion resistant grey cast iron. The method starts with melting of iron sources to form molten alloy. Then, composition of Fe-Nb and Fe-Al are added into the molten alloy and heated to a first predetermined temperature. After heating, Co, composition of Fe-Cr and Fe-Al are added into the molten alloy and then heating the molten alloy to a second predetermined temperature for a predetermined time. Then the molten alloy is subjected to casting at a third predetermined temperature. The high strength wear and corrosion resistant grey cast iron of the present disclosure comprises graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and balance being pearlite microstructure and exhibits tensile strength ranging from 280 MPa to 380 MPa and hardness ranging from 195 BHN to 220 BHN.

Description

A HIGH STRENGTH WEAR AND CORROSION RESISTANT GREY CAST IRON AND A METHOD OF MANUFACTURING THEREOF

TECHNICAE FIEED

[001] Present disclosure in general relates to a field of material science and metallurgy. Particularly, but not exclusively, the present disclosure relates to a high strength wear and corrosion resistant grey cast iron. Further embodiments of the disclosure disclose a method for manufacturing the high strength wear and corrosion resistant grey cast iron which exhibits 280 MPa - 380 MPa of tensile strength and 195 BHN - 220 BHN of hardness.

BACKGROUND OF THE DISCEOSURE

[002] Disc brake rotors are generally manufactured by using grey cast iron, which has good damping characteristics, low cost, high thermal conductivity and compression strength. However, such brake discs are prone to frequent rusting, which leads to decrease in desirable properties, such as strength, hardness, wear resistance and the like, whereby leading to failure. Many attempts have been made to increase strength of the grey cast iron, however, such attempts affect graphite flakes and in-tum damping properties of the grey cast iron.

[003] There have been several developments in the field of production of grey cast iron alloys which poses good combination of strength, damping properties, and reduction in weight, to address the afore-mentioned concerns. One such known process for manufacturing heat- resistant brake discs may be by using various alloying elements such as Si, Mn, Cr, Nb, Ti, Mo, Cu, Ni, V, and Pb, however, such composition of the alloy compromises on other properties such as wear resistance and corrosion resistance. Another document discloses about a low carbon, low boron and high chromium alloy steel which exhibits high hardness, impact resistance, wear resistance and toughness. However, requirement of alloying elements in higher content increases cost of the alloy. Also, in the field of manufacturing automobile components such as disc brake rotors, grey cast iron is preferred material over steel due to characteristics such as accessibility, durability, workability, formability, and cost of manufacturing and servicing. [004] In order to overcome the problems in above mentioned prior arts, there is a need for the development of grey cast iron alloys which exhibit high strength, high hardness, good corrosion and wear resistance, and reduction in weight of the alloy.

SUMMARY OF THE DISCLOSURE

[005] One or more shortcomings of the prior art are overcome by method as disclosed and additional advantages are provided through the method as described in the present disclosure.

[006] Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

[007] In one non-limiting embodiment, a high strength wear and corrosion resistant grey cast iron is disclosed. The grey cast iron comprises composition of carbon (C) in a range of 3.4 wt% to 4.6 wt%, silicon (Si) in a range of 1.5 wt% to 2.5 wt%, manganese (Mn) in a range of 0.5 wt% to 1.2 wt%, phosphorus (P) up-to 0.09 wt%, sulphur (S) up-to 0.1 wt%, chromium (Cr) in a range of 0.3 wt% to 0.8 wt%, aluminium (Al) in a range of 0.5 wt% to 3 wt%, cobalt (Co) in a range of 1.5 wt% to 4.0 wt%, copper (Cu) in a range of 0.3 wt% to 0.8wt%, tin (Sn) upto 0.08 wt%, niobium (Nb) in a range of 0.1 wt% to 0.6 wt%, and the balance being iron (Fe) optionally along with incidental elements.

[008] In an embodiment, the high-strength wear and corrosion resistant grey cast iron comprises graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and balance being pearlite microstructure.

[009] In an embodiment, the high-strength wear and corrosion resistant grey cast iron exhibits tensile strength ranging from 280 MPa to 380 MPa and hardness ranging from 195 BHN to 220 BHN.

[0010] In an embodiment, high-strength wear and corrosion resistant grey cast iron comprises hard carbide precipitates in the microstructure and AI2O3 layer on the outer surface.

[0011] In another non-limiting embodiment of the disclosure, a method for manufacturing high-strength wear and corrosion resistant grey cast iron is disclosed. The method comprises steps of melting predefined quantity of iron from iron sources to form a molten metal and then adding composition of Fe-Nb and Fe-Al into the molten metal to form molten alloy. Then heating the molten alloy to a first predetermined temperature, followed by adding Co, composition of Fe-Cr and composition of Fe-Mn into the molten alloy and heating to a second predetermined temperature for a predetermined time. The method further includes casting of a high-strength wear resistant corrosion resistant grey cast iron at a third predetermined temperature, comprising composition of: carbon (C) in a range of 3.4 wt% to 4.6 wt%, silicon (Si) in a range of 1.5 wt% to 2.5 wt%, manganese (Mn) in a range of 0.5 wt% to 1.2 wt%, phosphorus (P) up-to 0.09 wt%, sulphur (S) up-to 0.1 wt%, chromium (Cr) in a range of 0.3 wt% to 0.8 wt%, aluminium (Al) in a range of 0.5 wt% to 3 wt%, cobalt (Co) in a range of 1.5 wt% to 4.0 wt%, copper (Cu) in a range of 0.3 wt% to 0.8wt%, tin (Sn) up-to 0.08 wt%, niobium (Nb) in a range of 0.1 wt% to 0.6 wt%, and the balance being iron (Fe) optionally along with incidental elements.

[0012] In an embodiment, the high-strength wear and corrosion resistant grey cast iron includes graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and balance being pearlite microstructure.

[0013] In an embodiment, the high-strength wear and corrosion resistant grey cast iron exhibits tensile strength ranging from 280 MPa to 380 MPa and hardness ranging from 195 BHN to 220 BHN.

[0014] In an embodiment, high-strength wear and corrosion resistant grey cast iron includes hard carbide precipitates in the microstructure and AI2O3 layer on the outer surface.

[0015] In an embodiment, the method includes stacking a predefined quantity of iron procured from a plurality of iron sources. The plurality of iron sources include at least one of steel scrap, pig iron and Ferro-silicon (Fe-Si).

[0016] In an embodiment, the method includes stacking of iron sources in sandwiched layers enclosed with graphitizer during melting.

[0017] In an embodiment, the first predetermined temperature ranges from 1300 °C to 1385°C.

[0018] In an embodiment, the second predetermined temperature ranges from 1450 °C to 1480 °C, and the predetermined time of 15 minutes. [0019] In an embodiment, the third predetermined temperature ranges from 1500 °C to 1550°C.

[0020] In yet another non-limiting embodiment, there is provided a brake rotor for a vehicle, the brake rotor manufactured from a grey cast iron. The brake rotor comprising composition of carbon (C) in a range of 3.4 wt% to 4.6 wt%, silicon (Si) in a range of 1.5 wt% to 2.5 wt%, manganese (Mn) in a range of 0.5 wt% to 1.2 wt%, phosphorus (P) up-to 0.09 wt%, sulphur (S) up-to 0.1 wt%, chromium (Cr) in a range of 0.3 wt% to 0.8 wt%, aluminium (Al) in a range of 0.5 wt% to 3 wt%, cobalt (Co) in a range of 1.5 wt% to 4.0 wt%, copper (Cu) in a range of 0.3 wt% to 0.8wt%, tin (Sn) up-to 0.08 wt%, niobium (Nb) in a range of 0. 1 wt% to 0.6 wt%, and the balance being iron (Fe) optionally along with incidental elements.

[0021] In an embodiment, the brake rotor comprises graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and balance being pearlite microstructure.

[0022] In an embodiment, the brake rotor exhibits tensile strength ranging from 280 MPa to 380 MPa and hardness ranging from 195 BHN to 220 BHN.

[0023] In an embodiment, brake rotor comprises hard carbide precipitates in the microstructure and AI2O3 layer on the outer surface.

[0024] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.

[0025] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

[0026] BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

[0027] The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

[0028] Figure 1 is a flowchart illustrating a method for producing high strength wear and corrosion resistant grey cast iron, according to an exemplary embodiment of the present disclosure.

[0029] Figures 2a-2d illustrates microstructure of the high strength wear and corrosion resistant grey cast iron, according to an exemplary embodiment of the present disclosure.

[0030] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

[0031] DETAILED DESCRIPTION

[0032] The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the description of the disclosure. It should also be realized by those skilled in the art that such equivalent methods do not depart from the scope of the disclosure. The novel features which are believed to be characteristic of the disclosure, as to method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

[0033] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. [0034] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure.

[0035] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a method that comprises a list of acts does not include only those acts but may include other acts not expressly listed or inherent to such method. In other words, one or more acts in a method proceeded by “comprises. . . a” does not, without more constraints, preclude the existence of other acts or additional acts in the method. [0036] Embodiments of the present disclosure discloses a high strength wear and corrosion resistant grey cast iron and a method for manufacturing or producing a high strength wear and corrosion resistant grey cast iron. In this context, the present disclosure is directed to a method for manufacturing grey cast iron for disc brake rotor having improved properties including strength, hardness, wear and corrosion resistance.

[0037] Henceforth, the present disclosure is explained with the help of figures for a method of manufacturing high strength wear and corrosion resistant grey cast iron. However, such exemplary embodiments should not be construed as limitations of the present disclosure, since the method may be used on other types of cast iron where such need arises. A person skilled in the art can envisage various such embodiments without deviating from scope of the present disclosure.

[0038] Figure. 1 is an exemplary embodiment of the present disclosure illustrating a flowchart depicting a method for manufacturing high strength wear and corrosion resistant grey cast iron. In the present disclosure, mechanical properties including, but not limited to, strength, hardness, wear resistance and corrosion resistance may be improved without compromising some of the properties such as formability and hole expansion ratio. The grey cast iron produced by the method of the present disclosure includes microstructures such as graphite fakes, ferrite, pearlite microstructure and any other impurities having minimal proportion in microstructure which may impart minimal to no changes in properties of said grey cast iron. [0039] The method is now described with reference to the flowchart blocks and is as below. The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement the method. Additionally, individual blocks may be deleted from the methods without departing from the scope of the subject matter described herein. The method is particularly applicable to high strength wear and corrosion resistant grey cast iron.

[0040] At block 101, molten metal of iron may be formed by melting of iron from one or more sources. The iron may be melted in a furnace or in a crucible positioned in an oven, where the furnace may be for example, a blast furnace, shaft furnace, air melting furnace and vacuum furnace or the like, while the oven may be, for example, a microwave oven. Additionally, other type of apparatus capable of melting iron and producing molten metal may be employed without considering to limitation of the present disclosure. For melting, a predefined quantity of iron procured from a source of iron may be employed. Also, the predefined from iron may be procured from a mixture of plurality of iron sources [or interchangeably referred to “sources of iron”] which may be subjected to stacking and heating. In an embodiment, the plurality of iron sources may include steel scrap, raw pig iron, Ferrosilicon (Fe-Si) and any other source from which substantial proportion of iron may be obtained on melting. Here, the term “substantial” may refer to at least 97% of iron being obtained from such plurality of sources of iron. Further, the plurality of iron sources may be enclosed with graphitizer. In an embodiment, the plurality of iron sources may be subjected to at least one of stacking, layering, crushing, blending, and the like, where each of such plurality of sources may be sandwiched with layers of one another for mixing and forming of the molten metal with substantial uniform consistency in proportion of iron, such as at least 98% in consistency.

[0041] At block 102, the method comprises of adding ferro alloying elements such as Ferro Niobium (Fe-Nb) and Ferro Aluminium (Fe-Al). Also, composition of Fe-Nb may be added into the molten metal during or after the plurality of iron sources starts melting. Further, composition of Fe-Al may be added into the molten alloy after adding Fe-Nb. In an embodiment, elements may be added to the molten metal in sequence of introduction described herein. Alternatively, such elements may be introduced simultaneously or during addition of the plurality of iron sources of iron into the apparatus for melting. In an embodiment, introduction of elements may be a combination and a sequential addition into the molten metal. In an embodiment, mode of addition and/or introduction of such elements may be performed by lances, conveyors and the like that may be the apparatus for melting of the sources of iron.

[0042] The method further includes a step of heating the molten alloy to a first predetermined temperature [shown in block 103], In an embodiment, the first predetermined temperature ranges from 1300 °C to 1385 °C. Heating may be performed in the apparatus by means of conduction, induction and/or radiation, while other mode of heat transfer may also be applied for heating of material and/elements along with the sources of iron in the heating apparatus.

[0043] At block 104, the method further comprises of adding cobalt (Co), composition of Ferro chrome and Ferro Manganese (Fe-Mn) into the molten alloy. After adding Co, Fe-Cr and Fe- Mn into the molten alloy, the molten alloy may be subjected to heating to a second predetermined temperature for a predetermined time. In an embodiment, the second predetermined temperature ranges from 1450 °C to 1480 °C and the predetermined time of 15 minutes. Due to such configuration, resultant molten alloy is reheated prior casting, in order to improve properties such as strength, wear resistance and corrosion resistance.

[0044] Referring to block 105, the method comprises a step of casting a high strength wear and corrosion resistant grey cast iron at a third predetermined temperature. In an embodiment, the third predetermined temperature ranges from 1500 °C to 1550 °C.

[0045] Composition of the high strength wear and corrosion resistant grey cast iron comprises carbon (C) in a range of 3.4 wt% to 4.6 wt%, silicon (Si) in a range of 1.5 wt% to 2.5 wt%, manganese (Mn) in a range of 0.5 wt% to 1.2 wt%, phosphorus (P) up-to 0.09 wt%, sulphur (S) up-to 0.1 wt%, chromium (Cr) in a range of 0.3 wt% to 0.8 wt%, aluminium (Al) in a range of 0.5 wt% to 3 wt%, cobalt (Co) in a range of 1.5 wt% to 4.0 wt%, copper (Cu) in a range of 0.3 wt% to 0.8 wt%, tin (Sn) up-to 0.08 wt%, niobium (Nb) in a range of 0.1 wt% to 0.6 wt%, and the balance being iron (Fe) optionally along with incidental elements. The incidental elements may be elements which are unavoidable in the alloy composition and are present in minute quantities in flux, coke, additives or impurities. There may also be a possibility of the micro alloying elements to precipitate out and it may then become difficult to completely dissolve the precipitates in the subsequent reheating process rendering them ineffective for precipitation strengthening. [0046] The grey cast iron processed by the method of the present disclosure results in microstructural changes to form high strength wear and corrosion resistant grey cast iron. In an embodiment, the high strength wear and corrosion resistant grey cast iron comprises graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and the balance being pearlite microstructure. Further, microstructure of the high strength wear and corrosion resistant grey cast iron comprises hard carbide precipitates and AI2O3 layer on the outer surface. In an embodiment, the presence of graphite flakes in the microstructure increases the strength of grey cast iron. Further, the combination of graphite flakes and hard carbide precipitates in the microstructure results in high wear resistance. Further, AI2O3 layer on the outer surface of grey cast iron along with the combination of graphite flakes and hard carbide precipitates in the microstructure of grey cast iron increases the resistance to corrosion and rusting.

[0047] In an embodiment, the high-strength wear and corrosion resistant grey cast iron exhibits tensile strength ranging from 280 MPa to 380 MPa. Further, the high strength wear and corrosion resistant grey cast iron exhibits hardness ranging from 195 BHN to 220 BHN.

[0048] The following portions of the present disclosure provides details about the proportion of each alloying element in a composition of the steel and their role in enhancing properties.

[0049] Carbon (C) may be used in the range between 3.4 wt% to 4.6 wt%. Carbon is present in the form of graphite and results in a softer iron, more machinable, reduces shrinkage and reduces density.

[0050] Silicon (Si) may be used minimum in the range of 1.5 wt% to 2.5 wt%. Silicon suppresses the carbide formation and promotes the development of graphite when it is added to about 1.5 wt%. Higher Si contents increase the graphitization potential as well as castability of iron.

[0051] Manganese (Mn) may be used in the range of 0.5 wt% to 1.2 wt%. Mn increases the tensile strength and hardenability of grey cast iron and control the adverse effect of sulphur on the mechanical properties if grey cast iron. Addition of Mn counters the brittleness which occurs from sulphur in the grey cast iron. [0052] Chromium (Cr) may be used in the range 0.3 wt% to 0.8 wt%. This addition may substantially increase the strength, hardness and wear resistance and corrosion resistance of the grey cast iron.

[0053] Aluminium (Al) may be used in the range 0.5 wt% - 3 wt%. Minimum Al of 0.5 wt% is required to achieve graphitization and enables effective rust prevention and above 3 wt% may form brittle compounds and may reduce the toughness of the material.

[0054] Cobalt (Co) may be used in the range in between to 1.5 to 4 wt%. Cobalt below 1.5 wt% promotes softening of material with lump of bulky graphite and above 4 wt% restrict the carbide formation and thus diminish the effect of Nb and reduces the hardness.

[0055] Copper (Cu) may be added in the range of 0.3 wt% to 0.8 wt%. Cu addition may increase the hardness and tensile strength of the grey cast iron. Copper inhibits the formation of cementite and increase the hardenability, wear resistance and corrosion resistance of the grey cast iron.

[0056] Tin (Sn) may be added up to 0.08 wt%. The addition of tin increases the tensile strength of the grey cast iron and promotes the formation of pearlite. Excess addition may reduce the tensile strength of the grey cast iron.

[0057] Niobium (Nb) may be added in range of 0.1 wt% to 0.6 wt%. Addition of Nb in grey cast iron promotes the refinement of graphite structure, precipitation of small carbides and increases the hardness.

[0058] Example:

[0059] Further embodiments of the present disclosure will be now described with examples of particular compositions of the grey cast iron. Results have been compared on various fronts to show the effect of various alloying elements in improvement of strength, wear and corrosion resistance of the grey cast iron. The compositions of the grey cast iron that are assessed are as shown in below table 1.

Table - 1

Cueq(Nb) = Cu + Mn/2 + 6Cr/5 + 10 Sn + 2 Nb - (1)

CE = C + Si/3 - (2)

[0060] In an embodiment of the present disclosure, various experiments were carried out on the grey cast iron sample with varying composition as mentioned in Table - 1. For conducting the experiment, the grey cast iron specimens of pre-determined dimensions may be prepared by the method of the present disclosure. In an embodiment of the present disclosure, tensile straining for all the grey cast iron samples were carried out in tensile tester machine. A tensile test may involve mounting the specimen in a machine, such as the sample is subjecting to constant strain. For each set of compositions, tensile strength values are tabulated in Table -1. Further, the hardness testing may involve mounting the specimen in a Brinell Hardness testing machine and the hardness values are tabulated in Table- 1. Further, the copper equivalent and carbon equivalent values can be calculated from the equations 1 and 2 respectively and the obtained values are tabulated in Table 1.

[0061] In an embodiment, the conventional grey cast iron FG260 exhibits mechanical properties such as tensile strength ranging from 175 MPa - 250 MPa and hardness ranging from 160 BHN - 196 BHN. In an embodiment, the high strength wear and corrosion resistant grey cast iron produced by the method of disclosure indicates the improvement in mechanical properties such as tensile strength ranging from 280 MPa to 380 MPa and hardness ranging from 195 BHN to 220 BHN as indicated in Table - 1.

Table - 2

[0062] As evident from the Table -2, tensile strength and hardness values are reduced due to decrease in content of Al and Co in the chemical composition of grey cast iron samples. Therefore, minimum content of Al 0.5 % is required to achieve graphitization and requires for effective rust prevention. Further, Al content of above 3% may form brittle compounds and may reduce toughness of material. To ensure content of Al is within defined limit for imparting desired properties, proportion of addition of Ferro Niobium (Fe-Nb) and Ferro Aluminium (Fe- Al) is monitored by determining concentration of Al either composition of molten alloy during formation or from slag.

[0063] In an embodiment, Cobalt below 1.5% promotes softening of material with lump of bulky graphite and above 4% restrict the carbide formation and thus diminish the effect of Nb addition and reduces the hardness of grey cast iron.

[0064] Referring to figures. 2a - 2d, which are exemplary embodiments of the present disclosure, illustrating microstructure of the high strength wear and corrosion resistant grey cast iron sample. Figure 2a represents the microstructure of grey cast iron with pearlite and ferrite phases. Further, figure 2b indicates the microstructure of grey cast iron with refined graphite flakes. In an embodiment, the presence of Nb in the grey cast iron ensures refinement of graphite flakes and the refined graphite flakes increases the strength of the grey cast iron. As shown in Figure 2c, the microstructure of the grey cast iron represents the presence of combination of graphite flakes and hard carbide precipitates, which results in high wear resistance of the grey cast iron. In an embodiment, hard carbide precipitates formation is aided by the presence of Nb and Cr in the grey cast iron. Figure 2d represents the presence of AI2O3 layer on the outer surface of grey cast iron with microstructure comprising graphite flakes and hard carbide particles. In an embodiment, presence of Al with minimum of 0.5 wt% in grey cast iron helps in the formation of AI2O3 layer on the outer surface of the grey cast iron which prevents rusting and increases the resistance to corrosion and rusting. [0065] However, this composition should not be construed as a limitation to the present disclosure as it could be extended to other compositions of the grey cast iron as well.

[0066] In an embodiment of the present disclosure, the high strength wear and corrosion resistant grey cast iron of the present disclosure may be used any application including but not limiting to automotive applications to manufacture structural components like brake rotor, brake discs, and the like. The high strength wear and corrosion resistant grey cast iron of the present disclosure may be used in any other industrial structural applications.

Equivalents:

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Referral Numerals

Claims

Claims:

1. A high-strength wear and corrosion resistant grey cast iron, comprising: composition of: carbon (C) in a range of 3.4 wt% to 4.6 wt%, silicon (Si) in a range of 1.5 wt% to 2.5 wt%, manganese (Mn) in a range of 0.5 wt% to 1.2 wt%, phosphorus (P) up-to 0.09 wt%, sulphur (S) up-to 0.1 wt%, chromium (Cr) in a range of 0.3 wt% to 0.8 wt%, aluminium (Al) in a range of 0.5 wt% to 3 wt%, cobalt (Co) in a range of 1.5 wt% to 4.0 wt%, copper (Cu) in a range of 0.3 wt% to 0.8wt%, tin (Sn) up-to 0.08 wt%, niobium (Nb) in a range of 0.1 wt% to 0.6 wt%, and the balance being iron (Fe) optionally along with incidental elements.

2. The high-strength wear and corrosion resistant grey cast iron as claimed in claim 1 wherein the high-strength wear and corrosion resistant grey cast iron comprises graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and balance being pearlite microstructure.

3. The high-strength wear and corrosion resistant grey cast iron as claimed in claim 1, wherein the high-strength wear and corrosion resistant grey cast iron exhibits tensile strength ranging from 280 MPa to 380 MPa.

4. The high-strength wear and corrosion resistant grey cast iron as claimed in claim 1, wherein the high-strength wear and corrosion resistant grey cast iron exhibits hardness ranging from 195 BHN to 220 BHN.

5. The high-strength wear and corrosion resistant grey cast iron as claimed in claim 1, wherein the high-strength wear and corrosion resistant grey cast iron comprises hard carbide precipitates in the microstructure and AI2O3 layer on the outer surface.

6. A method for manufacturing a high-strength wear and corrosion resistant grey cast iron, the method comprising: melting, predefined quantity of iron to form a molten metal; adding, composition of Fe-Nb, and Fe-Al into the molten metal to form molten alloy; heating, the molten alloy to a first predetermined temperature; adding, Co, composition of Fe-Cr and composition of Fe-Mn into the molten alloy and heating to a second predetermined temperature for a predetermined time; casting, a high-strength wear resistant corrosion resistant grey cast iron at a third predetermined temperature, the composition of the high-strength wear resistant corrosion resistant grey cast iron comprising: carbon (C) in a range of 3.4 wt% to 4.6 wt%, silicon (Si) in a range of 1.5 wt% to 2.5 wt%, manganese (Mn) in a range of 0.5 wt% to 1.2 wt%, phosphorus (P) up-to 0.09 wt%, sulphur (S) up-to 0. 1 wt%, chromium (Cr) in a range of 0.3 wt% to 0.8 wt%, aluminium (Al) in a range of 0.5 wt% to 3 wt%, cobalt (Co) in a range of 1.5 wt% to 4.0 wt%, copper (Cu) in a range of 0.3 wt% to 0.8 wt%, tin (Sn) up-to 0.08 wt%, niobium (Nb) in a range of 0.1 wt% to 0.6 wt%, and the balance being iron (Fe) optionally along with incidental elements, the grey cast iron having improved properties of strength, wear resistance and corrosion resistance.

7. The method as claimed in claim 6, wherein the high-strength wear and corrosion resistant grey cast iron comprises graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and balance being pearlite microstructure.

8. The method as claimed in claim 6, wherein the method includes stacking a predefined quantity of iron procured from a plurality of iron sources. The method as claimed in claim 11, wherein the plurality of iron sources include steel scrap, pig iron and Ferro-silicon (Fe-Si). The method as claimed in claim 6, comprises stacking of iron sources in sandwiched layers enclosed with graphitizer during melting. The method as claimed in claim 6, wherein the first predetermined temperature ranges from 1300 °C to 1385 °C. The method as claimed in claim 6, wherein the second predetermined temperature ranges from 1450 °C to 1480 °C, and the predetermined time of 15 minutes. The method as claimed in claim 6, wherein the third predetermined temperature ranges from 1500 °C to 1550 °C. A brake rotor for a vehicle, the brake rotor manufactured from a grey cast iron, comprising composition of: carbon (C) in a range of 3.4 wt% to 4.6 wt%, silicon (Si) in a range of 1.5 wt% to 2.5 wt%, manganese (Mn) in a range of 0.5 wt% to 1.2 wt%, phosphorus (P) up-to 0.09 wt%, sulphur (S) up-to 0.1 wt%, chromium (Cr) in a range of 0.3 wt% to 0.8 wt%, aluminium (Al) in a range of 0.5 wt% to 3 wt%, cobalt (Co) in a range of 1.5 wt% to 4.0 wt%, copper (Cu) in a range of 0.3 wt% to 0.8 wt%, tin (Sn) up-to 0.08 wt%, niobium (Nb) in a range of 0.1 wt% to 0.6 wt%, and the balance being iron (Fe) optionally along with incidental elements. The brake rotor as claimed in claim 14, wherein the brake rotor comprises graphite flakes of 7 % to 12 %, ferrite microstructure of less than 5 % and balance being pearlite microstructure.

16. The brake rotor as claimed in claim 14, wherein the brake rotor comprises hard carbide precipitates in the microstructure and AI2O3 layer on the outer surface.