DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A SYSTEM AND METHOD FOR DEVELOPMENT OF SPECIAL 2J FINISH ON STEEL SHEETS / COILS FOR ROLLING STOCKS

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru - 560 027,
Karnataka, India

The following specification particularly describes the invention and the manner in which it is to be performed

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present invention claims priority from Indian patent application numbered IN 202041049383 filed on 12th November, 2020.

TECHNICAL FIELD
[002] The present subject matter described herein, in general, relates to a surface finishing of stainless steel and more specifically relates to a system and method for development of surface finishing of the stainless steel for a rolling stock.
BACKGROUND OF THE INVENTION
[003] The rolling stocks are manufactured by the special austenitic grade stainless steel sheets/coils with specific chemical, mechanical, metallurgical IGC corrosion tests, dimensional tolerances as per standard specification. These steel sheets/coils also needs to have specific surface finish, depending on the requirements specified by customer. In the earlier, the side wall material of rolling stock is of stainless steel of imported DLT-DF (Dead line temper-Dull finish). The 2J finish on the normal stainless steel grade is obtained by a scrotch-brite brushing technology for rolling stock.
[004] Thus, for closely matching to gloss reflectance and surface roughness values (Ra) of the stainless steel as per standard specification and to maintain consistent finish for the entire project, the special 2J finish is achieved on stainless steel for rolling stock through special rolling and grinding route.
OBJECTS OF THE INVENTION
[005] Main object of the present invention is to develop the special 2J finish on the steel sheets / coils for rolling stocks.
[006] Another object of present invention is development/ establishment of the specification, after freezing the range of gloss reflectance & surface roughness values to achieve consistency.
[007] Another object of the present invention is to achieve the special 2J finish on the steel sheets / coils through the special cold rolling and the strip grinding route.
[008] Yet another object of the present invention is to achieve and match the gloss reflectance and the surface roughness values of special 2J finished steel as per standard values
[009] Yet another objective is the maintain/ achieve consistent finish for the entire project.
SUMMARY OF THE INVENTION
[0010] Before the present system is described, it is to be understood that this application is not limited to the particular machine or an apparatus, and methodologies described, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to the system and method for development of special 2J finish on steel sheets / coils for rolling stocks through special rolling and grinding route, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[0011] The present subject matter described herein, in general, relates to the surface finishing of the stainless steel for a rolling stock. The special 2J finish is achieved on stainless steel surface of exterior/side walls of rolling stock through special rolling and the strip grinding line (No.3 Finish).
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawing. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the drawing:
[0013] The detailed description is described with reference to the accompanying figure. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components.
[0014] Figure 1 illustrates process flowchart for achieving the special 2J finishing through the rolling and the strip grinding line (No.3 Finish).
[0015] Figure 2 illustrates the stainless steel sheets developed after the existing surface finish and the stainless steel sheets after the special 2J finish.
[0016] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF THE INVENTION
[0017] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, systems and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0018] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0019] The rolling stocks are manufactured by the special austenitic grade stainless steel sheets / coils with specific chemical, mechanical, metallurgical IGC corrosion tests, dimensional tolerances as per standard specification. These steel sheets / coils also need to have specific surface finish.
[0020] The special 2J finish is achieved on stainless steel surface of exterior/side walls of rolling stock through special rolling and the strip grinding line (No.3 Finish Line). This development of special 2J finish on stainless steel sheets / coils closely matching to gloss reflectance and surface roughness values (Ra) as specified. Since the finish has to be the same for the entire stainless steel surface, consistency in gloss values and surface roughness values is maintained.
[0021] Also this finish consistency should be maintained for all the products, since the products are unpainted.
[0022] Referring to figure 1, in one aspect of the present invention, process flowchart for achieving the special 2J finishing on stainless steel through the rolling and the strip grinding line (No.3 Finish) is disclosed. In this process the molten steel from the furnace is forwarded for hot rolling process wherein, the molten steel is converted into stainless steel sheets of desired thickness. The stainless steel sheets are further processed through annealing and pickling line to reverse the effects of hardening to avoid cracking of metal during bending and to remove surface oxides from the metal for exposing the bare metal. Further the stainless sheets are processed through cold rolling for increasing the strength of the metal and its surface finish. The combination of cold rolling, Annealing & pickling, ensures mechanical properties as per required specification. The stainless steel sheets are again processed through annealing and pickling process. The stainless steel sheets are then processed through the strip grinding line (SGL) wherein, the sheet is polished with different grits of belts varying from 100 to 120 to achieve the desired finish. Uniform finish is ensured throughout the steel sheet/coil by controlling the speed of the line, grinding head load, frequency of belt changing. The surface is visually verified with approved sample for every 50 meters, to ensure consistency, by measuring the gloss reflectance & surface roughness values and also by visual comparison with standard sample. The stainless steel sheets are then processed through the skin pass mill process wherein, a desired surface roughness is achieved for the sheets. The required finishing lines are then made on the sheets for design purpose and the sheets are packed.
[0023] Accordingly, the present invention discloses a system and method for development of special 2J finish on steel sheets / coils for rolling stocks comprising of special rolling and the strip grinding line for providing gloss reflectance and surface roughness on stainless steel sheets/ coils.
[0024] The system is configured to polish the steel sheet/ coil with different grits of belts varying from100 to 120 to achieve the predetermined finish. The system is configured to provide uniform finish to the entire stainless steel sheet/ coil by controlling the speed of the line, grinding head load, frequency of belt changing. The stainless sheets are processed through annealing and pickling process. The system is configured to provide stainless steel sheet for manufacturing of exterior and inner walls of Metro rails and alike products, and also ensured consistent finish for the entire project.
[0025] The method for manufacturing a special 2J finish on steel sheets/coils for rolling stocks is performed in the following steps:
• Melting the steel in the furnace to obtain molten steel.
• Hot rolling of the molten steel to obtain stainless steel sheets of predetermined thickness.
• Annealing and pickling the stainless steel sheets.
• Cold rolling the stainless steel sheets for increasing the strength of the metal and its surface finish.
• Annealing and pickling the stainless steel sheets.
• Strip grinding the stainless steel sheets for special 2J finish.
• Processing the stainless steel sheets through skin pass mill for achieving predetermined roughness.
• Engraving the finishing lines on the stainless steel sheets for design purposes on the final product.
[0026] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features
[0027] Some object of the present invention is to develop the special 2J finish on the steel sheets / coils for rolling stocks.
[0028] Some object of the present invention is development/ establishment of the specification, after freezing the range of gloss reflectance & surface roughness values to achieve consistency
[0029] Some object of the present invention is to achieve the special 2J finish on the steel sheets / coils through the special cold rolling and the strip grinding route.
[0030] Some object of the present invention is to achieve and match the gloss reflectance and the surface roughness values of special 2J finished steel as per standard values.
[0031] Some object of the present invention is to maintain/ achieve consistent finish for the entire project.
,CLAIMS:
1. A system for development of special 2J finish on steel sheets / coils for rolling stocks comprises of special rolling and the strip grinding line for providing gloss reflectance and surface roughness on stainless steel sheets/ coils.

2. The system as claimed in claim 1 wherein, the system is configured to polish the steel sheet/ coil with different grits of belts.

3. The system as claimed in claim 1 wherein, the said belts vary from 100 to 120 to achieve the predetermined finish.

4. The system as claimed in claim 1 wherein, the system is configured to provide uniform finish to the entire stainless steel sheet/ coil by controlling the speed of the line, grinding head load, frequency of belt changing.

5. The system as claimed in claim 1 wherein, the said stainless sheets are processed through annealing and pickling process.

6. The system as claimed in claim 1 wherein, the system is configured to provide stainless steel sheet for manufacturing of exterior and inner walls of Metro rails and alike products.

7. The method for manufacturing a special 2J finish on steel sheets/coils for rolling stocks comprising the steps of:
• melting the steel in the furnace to obtain molten steel;
• hot rolling of the molten steel to obtain stainless steel sheets of predetermined thickness;
• annealing and pickling the stainless steel sheets;
• cold rolling the stainless steel sheets for increasing the strength of the metal and its surface finish;
• annealing and pickling the stainless steel sheets;
• strip grinding the stainless steel sheets for special 2J finish;
• processing the stainless steel sheets through skin pass mill for achieving predetermined roughness; and
• engraving the finishing lines on the stainless steel sheets for design purposes on the final product.