The present disclosure in general relates to a field of automobile. Particularly, but not exclusively, the present disclosure relates to a brake drum for a vehicle. Further embodiments of the disclosure disclose an alloy composition and a method of manufacturing the brake drum.
BACKGROUND OF THE DISCLOSURE
In automobiles and the like, friction materials such as brake pads and brake linings are used for braking. The friction material plays a role of braking by making frictional contact brake drum. For this reason, the friction material is required to have a good coefficient of friction, wear resistance (the friction material has a long life), impact strength, sound vibration (the brake noise and abnormal noise are unlikely to occur), and the like.
Conventional brake drums are manufactured by cast iron FG250 grade material. This material has issue of low impact strength, poor dampening properties, less surface roughness value and the like, thereby leading to decrease in service life of the brake drum, which is undesired.
Accordingly, there is a demand for a brake drum which is capable of realizing improvements in impact strength, surface roughness, wear resistance, as compared with FG250.
SUMMARY OF THE DISCLOSURE
One or more shortcomings of the prior art are overcome by the composition of brake drum and method of manufacturing the brake drum as disclosed and additional advantages are provided through the brake drum and method as described in the present disclosure.
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.
In one non-limiting embodiment of the present disclosure, a brake drum for a vehicle is disclosed. The brake drum includes an alloy composition in weight percentage (wt%) of carbon (C) at about 3% to about 3.3%, silicon (Si) at about 1.9% to about 2.2%, manganese (Mn) at about 0.8%) to about 0.85%, phosphorus (P) up-to 0.15%, sulphur (S) up-to 0.1%, aluminum (Al) at about 2.4% to 3.0% and the balance being Iron (Fe) optionally along with incidental

elements. The brake drum having the aforesaid alloy composition exhibits a better dampening properties, impact strength, surface roughness, ductility and the like.
In an embodiment, the brake drum exhibits hardness ranging from about 80 HRB to about 90 HRB.
In an embodiment, the brake drum comprises 'A' type graphitized microstructure, in area %, of about 90% to 95% and 'B' type graphitized microstructure, in area %, of about 5% to 10%. This microstructure helps in increasing damping properties, high impact strength, hardness and lower wear resistance.
In an embodiment, the brake drum exhibits a roughness average ranging from about 0.15 to 0.16.
In an embodiment, the brake drum exhibits an impact strength ranging from about 3.7 Nm to about 4.1 Nm.
In another non-limiting embodiment, there is provided a method for manufacturing the brake drum. The method initially starts from melting an alloy composition in weight percentage (wt%) of carbon (C) at about 3% to about 3.3%, silicon (Si) at about 1.9% to about 2.2%, manganese (Mn) at about 0.8% to about 0.85%, phosphorus (P) up-to 0.15%, sulphur (S) up-to 0. P/o, aluminum (Al) at about 2.4% to 3.0%> and the balance being Iron (Fe) optionally along with incidental elements. The melted alloy may be then tapped at a predetermined temperature. Upon tapping the melted alloy, the tapped alloy may be poured into a mould for a predetermined time from a ladle. The melted alloy is then cooled in the mould to form a brake drum.
In an embodiment, the predetermined temperature ranges from about 1430°C to about 1450°C. Melting and tapping at the predetermined temperature aids in reducing the earlier solidification and get uniform microstructure
In an embodiment, the predetermined time ranges from about 1.5 minutes to about 1.6 minutes.
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 to form a further embodiment of the disclosure.

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.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
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:
Figure. 1 illustrates a perspective view of a brake drum assembly, in according to an embodiment of the present disclosure.
Figure. 2 is a flowchart illustrating a method for manufacturing a brake drum for a vehicle, according to an embodiment of the present disclosure.
Figure. 3 illustrates a Scanning Electron Microscope [SEM] image showing microstructure of a conventional brake drum.
Figure. 4 illustrates Scanning Electron Microscope [SEM] image showing microstructure of the brake drum of the present disclosure, according to an embodiment of the present disclosure.
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.
DETAILED DESCRIPTION
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 characteristics 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.
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.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have 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 alternatives falling within the scope of the disclosure.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover non-exclusive inclusions, such that a method that includes 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.
Embodiments of the present disclosure discloses a brake drum for a vehicle and a method for manufacturing or producing the brake drum. Conventionally, brake drums are made of material such as cast iron FG250 grade. This material pose issues such as low impact strength, poor dampening properties, less surface roughness value and the like. Accordingly, the present disclosure disclose a brake drum having particular alloy composition which exhibits a better dampening properties, impact strength, surface roughness, ductility and the like. The brake drum of the present disclosure exhibits hardness ranging from about 80 HRB to about 90 HRB and roughness average ranging from about 0.15 to about 0.16 after subjecting to machining.

Further, the brake drum exhibits an impact strength ranging from about 3.7 Nm to about 4.1
Nm.
In the method of manufacturing the brake drum, a first step may include melting an alloy composition in weight percentage (wt%) of carbon (C) at about 3% to about 3.3%, silicon (Si) at about 1.9% to about 2.2%, manganese (Mn) at about 0.8% to about 0.85%, phosphorus (P) up-to 0.15%), sulphur (S) up-to 0.1%, aluminum (Al) at about 2.4% to 3.0%> and the balance being Iron (Fe) optionally along with incidental elements. The melted alloy may be then tapped at a predetermined temperature. Upon tapping the melted alloy, the tapped melted alloy may be poured into a mould for a predetermined time from a ladle. The melted alloy is then cooled in the mould to form the brake drum. In an embodiment, the predetermined temperature may range from about 1430°C to about 1450°C and the predetermined time may range from about 1.5 minutes to 1.6 minutes. In and embodiment, melting and tapping at the predetermined temperature aids in reducing the earlier solidification and get uniform microstructure.
The brake drum having the composition and manufactured by the method of the present disclosure includes 'A' type graphitized microstructure, in area %, of about 90% to 95% and 'B' type graphitized microstructure, in area %, of about 5% to 10%. This microstructure helps in increasing damping properties, high impact strength, hardness and lower wear resistance. Further, the brake drum exhibits hardness ranging from about 80 HRB to about 90 URB and roughness average ranging from about 0.15 to about 0.16 after subjecting to machining. Furthermore, the brake drum exhibits an impact strength ranging from about 3.7 Nm to about 4.1 Nm.
Henceforth, the method of manufacturing the brake drum of the present disclosure is explained with the help of figures. A person skilled in the art can envisage various such embodiments without deviating from scope of the present disclosure.
Figure. 1 is an exemplary embodiment of the present disclosure which illustrates a perspective view of a drum brake assembly (100). The drum brake assembly (100) may broadly include a brake drum (101), which nay be secured to a vehicle wheel (not shown in Figs) for rotation therewith. Interior of the brake drum is hollow, defining an inner cylindrical braking surface (104). Further, the drum brake assembly includes brake shoes (105) which are positioned on either sides of the inner cylindrical braking surface (104). The brake shoes (105) are configured to accommodate brake liners (103), where the brake liners (103) face towards the cylindrical

braking surface. Furthermore, the brake assembly may include an actuator (102) which may be configured to contact a portion of the brake shoes (105), to displace the brake shoes (105) such that, the brake liners abut the inner cylindrical braking surface (104) of the brake drum, to reduce speed or stop the wheels (thus, the vehicle).
Figure. 2 is exemplary embodiment of the present disclosure which illustrates a flowchart depicting a method for manufacturing a brake drum for a vehicle. In the present disclosure, dampening properties and mechanical properties such as impact strength, hardness and the like of the brake drum may be improved. The brake drum is produced by inclusion of aluminum at about 2.4% to 3.0% (wt%) in the composition, which aids in improving impact strength, roughness average (Ra) value and ductility of the brake drum. The method is now described with reference to the schematic representation and flowchart blocks.
At block 201, an alloy composition in weight percentage (wt%) of carbon (C) at about 3% to about 3.3%), silicon (Si) at about 1.9% to about 2.2%, manganese (Mn) at about 0.8%> to about 0.85%, phosphorus (P) up-to 0.15%, sulphur (S) up-to 0.1%, aluminum (Al) at about 2.4% to 3.0%) and the balance being Iron (Fe) optionally along with incidental elements, may be melted. In an embodiment, melting of the alloy composition may be performed in an induction furnace.
At block 202, the method includes tapping the melted alloy composition at a predetermined temperature. In an embodiment the melted alloy may be tapped into a ladle and the predetermined temperature may range from about 1430°C to about 1450°C heating.
Once, the melted alloy is tapped as per block 202, mould may be prepared, which includes sand mixing, pattern inspection, mould closing and core setting [as shown in block 203]. After preparing the mould, as seen in block 204 the tapped metal may be poured into the mould for a predetermined time from a ladle. In an embodiment, the predetermined time may be about 1.5 minutes to about 1.6 minutes. Pouring the tapped metal for the predetermined time aids in reducing turbulence and achieving uniform structure of the brake drum. Upon pouring the tapped melted alloy into the mould, the mould is allowed to cool for producing the brake drum (as seen in block 205). The brake drum manufactured with the composition and the method of the present disclosure results in microstructural changes to form the high strength brake drum. In an embodiment, the brake drum comprises 'A' type graphitized microstructure and 'B' type graphitized microstructure.

In an embodiment, the brake drum exhibits hardness ranging from about 80 HRB to about 90 HRB and roughness average (Ra) ranging from about 0.15 to about 0.16 after subjecting to machining. Furthermore, the brake drum exhibits an impact strength ranging from about 3.7 Nm to about 4.1 Nm.
Figure. 3 illustrates microstructure of the conventional brake drum. Conventional brake drum comprises 'A' type graphitized microstructure of about 70% (in area%) and 'B' type graphitized microstructure of about 30% (area%) [indicated by circles in Figure. 3]. Whereas, as seen in Figure. 4, the brake drum formed with composition and method of the present disclosure, consists of 'A' type graphitized microstructure of about 90% to 95% (in area %) and 'B' type graphitized microstructure of about 5% to 10% [indicated by circles in Figure. 4].
Following portions of the present disclosure, provides details about the proportion of each element in a composition of the high strength cold rolled steel sheet and their role in enhancing properties.
Carbon (C) may be used in the range of about 3% to about 3.3% (wt%). Carbon (C) in the form of graphite results in a softer iron, reduces shrinkage and decreases density.
Silicon (Si) may be used in the range of about 1.9% to 2.2% (wt%). Silicon (Si) is a graphite stabilizing element in cast iron. Silicon promotes the development of graphite in place of iron carbides.
Manganese (Mn) may be used in the range of about 0.8% to 0.85% (wt%). Manganese (Mn) helps in increasing impact energy and density. Manganese also helps in controlling adverse effect of sulphur on mechanical properties of the end product. Inclusion of excess Manganese (Mn) above the appropriate range may lead to decrease in wear co-efficient, hardness and graphitization.
Phosphorus (P) may be used up-to 0.15% (wt%). Phosphorous (P) of this proportion may help in maintaining appropriate amount of phosphide, which facilitates in improving mechanical properties of the end product. Inclusion of excess Phosphorus (P) above the appropriate range increases eutectic phosphide, which affects the mechanical properties.
Sulphur (S) may be used up-to 0.1% (wt%). Sulphur (S) acts as a tramp element and its level must be within appropriate range. Inclusion of excess Sulphur (S) above the appropriate range

may lead to development of Iron Sulphide (FeS) low melting phase, that will produce hot shortness.
Aluminum (Al) may be used in the range of about 2.4% to 3.0% (wt%). Aluminum (Al) of this range facilitates the end product to exhibit desired hardness. Further, Aluminum causes formation of ferrite matrix, which gives ductility and improving of impact resistance. Furthermore, excess inclusion of aluminum above the appropriate range would increase ferrite phase in microstructure, leading to decrease in hardness. Also, excess inclusion may lead to high porosity, blow hole and pin hole, which are detrimental to the brake drum.
Example:
Further embodiments of the present disclosure will be now described with an example of particular composition of the brake drum, which is selected from the composition range of the present disclosure, which are illustrated in Table 1. Further composition of the conventional brake drum is illustrated in Table 2. Experiments have been carried out for brake drum formed by the method and having composition of the present disclosure and the conventional brake drum. Results have been tabulated in Tables 1 and 2.

Element Wt%
Carbon 3.3
Silicon 2.1
Manganese 0.85
Phosphorous 0.15
Sulphur 0.10
Aluminum 3.0
Properties
Ra value 0.15
Porosity No porosity
Ductility High
Impact strength (Nm) 4.08
Damping properties High
Hardness 86HRB
Table: 1

Element Wt%
Carbon 3.35
Silicon 1.95
Manganese 0.75
Phosphorous 0.15
Sulphur 0.10
Aluminum NIL
Properties
Ra value 0.35
Porosity High porosity
Ductility Less
Impact strength (Nm) 3.26
Damping properties Less
Table: 2
In an embodiment of the present disclosure, various experiments were carried out on the brake drum manufactured by the method and composition of the present disclosure as mentioned in Table 1 and the conventional brake drum as mentioned in Table 2. Mechanical properties exhibited by the brake drum of the present disclosure and the conventional brake drum are shown in Table 1 and 2, respectively. As evident from the above tables, the brake drum having the composition and manufactured by the method of the present disclosure, exhibits better mechanical properties than the mechanical properties exhibited by the conventional brake drum. Accordingly, the brake drum of the present disclosure exhibits hardness ranging from about 80 HRB to about 90 HRB and roughness average ranging from about 0.15 to about 0.16 after subjecting to machining. Furthermore, the brake drum exhibits an impact strength ranging from about 3.7 Nm to about 4.1 Nm.
It should be understood that the experiments are carried out for particular compositions of the brake drum and the results brought out in the previous paragraphs are for the composition shown in Table 1. However, this composition should not be construed as a limitation to the present disclosure as it could be extended to other compositions within the range as disclosed in the preceding paragraphs, as well.

In an embodiment, the brake drum employs Aluminum of 2.4% to 3% (wt%) and the aluminum posses density of 2.4 gm/cm3. Hence, inclusion of aluminum facilitates in obtaining a density of 7.07 gm/cm3, thereby reducing weight of the brake drum.
While few embodiments of the present disclosure have been described above, it is to be understood that the disclosure is not limited to the above embodiments and modifications may be appropriately made thereto within the spirit and scope of the invention.
While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

Referral Numerals

Referral Numerals Description
100 Drum brake assembly
101 Brake drum
102 Actuator
103 Brake liner
104 Inner cylindrical braking surface
105 Brake shoes
201-205 Flowchart blocks
201 Melting stage
202 Tapping stage
203 Mould preparing stage
204 Pouring stage
205 Cooling stage

Claim:

1. A brake drum (101) for a vehicle, comprising:
an alloy composition in weight (wt%) percentage of: carbon (C) at about 3% to about 3.3%, silicon (Si) at about 1.9% to about 2.2%, manganese (Mn) at about 0.8% to about 0.85%, phosphorus (P) up-to 0.15%, sulphur (S)up-to 0.1%, aluminum (Al) at about 2.4% to 3.0%>, and the balance being Iron (Fe) optionally along with incidental elements.
2. The brake drum (101) as claimed in claim 1, wherein the brake drum (101) exhibits hardness ranging from about 80 HRB to about 90 HRB.
3. The brake drum (101) as claimed in claim 1, wherein the brake drum comprises 'A' type graphitized microstructure, in area %, of about 90% to 95% and 'B' type graphitized microstructure, in area %, of about 5% to 10%.
4. The brake drum (101) as claimed in claim 1, wherein the brake drum (101) exhibits a roughness average ranging from about 0.15 to 0.16.
5. The brake drum (101) as claimed in claim 1, wherein the brake drum (101) exhibits an impact strength ranging from about 3.7 Nm to about 4.1 Nm.
6. A vehicle comprising a brake drum (101) as claimed in claim 1.
7. A method for manufacturing a brake drum (101), the method comprising:
melting an alloy composition in weight percentage (wt%) of: carbon (C) at about 3% to about 3.3%, silicon (Si) at about 1.9% to about 2.2%, manganese (Mn) at about 0.8% to about 0.85%, phosphorus (P) up-to 0.15%, sulphur (S) up-to 0.1%, aluminum (Al) at about 2.4% to 3.0%>, and the balance being Iron (Fe) optionally along with incidental elements;

tapping, the melted alloy composition at a predetermined temperature; pouring, the tapped melted alloy composition into a mould for a predetermined time from a ladle; and
cooling the mould to form a brake drum (101).
8. The method as claimed in claim 7, wherein the predetermined temperature ranges from about 1430°C to about 1450°C.
9. The method as claimed in claim 7, wherein the predetermined time ranges from about 1.5 minutes to about 1.6 minutes.

10. The method as claimed in claim 7, wherein the brake drum (101) exhibits hardness ranging from about 80 HRB to about 90 HRB.
11. The method as claimed in claim 7, wherein the brake drum (101) comprises 'A' type graphitized microstructure, in area %, of about 90% to 95% and 'B' type graphitized microstructure, in area %, of about 5% to 10%.
12. The method as claimed in claim 7, wherein the brake drum (101) exhibits a roughness average ranging from about 0.15 to about 0.16, after subjecting to machining.
13. The method as claimed in claim 7, wherein the brake drum (101) exhibits an impact strength ranging from about 3.7 Nm to about 4.1 Nm.