FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
1 TITLE OF THE INVENTION :
THICK WEB ASYMMETRIC RAIL ROLLED SECTION AND A PROCESS FOR ITS PRODUCTION.

2 APPLICANT (S)
Name : Nationality :

STEEL AUTHORITY OF INDIA LIMITED.
A Govt, of India Enterprise;
Bhilai Steel Plant, Bhilai, State of Chattisgarh,India.


3 PREAMBLE TO THE DESCRIPTION
COMPLETE

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


FIELD OF THE INVENTION
The present invention relates to thick web asymmetrical rails suitable for application in railway track, switch/points and the like and process for production of such rails. More particularly, the present invention is directed to designing and developing thick web asymmetric rail to meet the requirements of the relevant specification with desired dimensional accuracy and tolerances and having the requisite strength, structural homogeneity and physical properties to suit the end applications in rail track, points/ switches or like applications for railway transportation to meet present as well as the projected demand in terms of quality and quantity. Importantly, the thick web asymmetric rail and its method of production have been provided to take care of requirements of metal flow characteristics, elongation co-efficient, spread, over/under filling in relation to the bar delivery. Advantageously, the method of production of the asymmetric rails further ensure that the bar is not twisted during the rolling process and load distribution ensure that none of the passes is over loaded in relation to rolling speed. The selective rolling scheme according to the present invention favour avoiding the problem of the metal getting twisted due to cutting of the asymmetric groove on the bottom rolls specially in finishing stands and has been taken care of by the differential distribution of the metal in the successive passes. The method of the production of thick web asymmetric rails further provide means for use of such rail to match with the conventional UIC-60 rail profile by simply forging one end of asymmetric rail for said desired matching and/or involving milling/machining as necessary. The rail-wheel profile on contact face is optimized in order to reduce the deflecting forces. The thick web asymmetric rails and its method of manufacture according to the present invention is thus adapted to meet standards and specification to suit railways and other users so as to effect import substitution and providing cost effective design as well as process of production utilizing indigenous resources, favour wide scale industrial application for manufacturing these special rail sections.
BACKGROUND ART
Conventional rolling of rails in any rail rolling mill is done by either using tongue and groove pass design or diagonal rolling method. The most recent process introduces universal rail design in which all the elements e.g. head, foot and flange are worked upon independently by rolls. In one of the steel plants of the applicants the rails are being rolled using diagonal

pass design which includes seven pass rolling at roughing stand and seven passes at the intermediate and finishing stands. Thus a total of 14 passes are required to produce the finish rail section from blooms. The flat bottom symmetric rails designated as R-52 and UIC-60 rails conforming to IRS-T12-2009 specifications are symmetric about the vertical axis. Hence all the portions of the rail section i.e. the flange, the head and the web are equally distributed with respect to vertical line in linear units i.e. the section profiles of these rails are bi-laterally symmetrical.
The thick-web rails on the other hand, has an asymmetric section. A continuous requirement for such thick web asymmetric rail section has been rising in demand projections of the railway transportation sector. The existing demand is being met through export only as there is no indigenous producer of this type of rails. It has been seen to be an opportunity for the manufacturers of standard rail sections for enhancing the product mix of rail and structural mills by adding value to the existing product range with high realization per ton of produce as the special section rail products and particularly saving on expense of foreign currency by way of import substitution and supplying the railways in a more complete manner. There being very limited producers for the thick web asymmetric rails all over the world, the product has immense potential for export and earning foreign exchange.
There has therefore been a persistent demand in the art for developing the thick web asymmetric rails for use by railways and other purposes including the switch manufacturers and a method for its production involving the rolling scheme and roll pass design as well as the roll groove machining to meet the dimensional accuracy and tolerances complying with the applicable standards and specifications. It is also important that the facility for existing product range for the standard rail sections are utilized while modifications are considered and catering to demands for the entire range of rail sections. The invention thus provide means for production of thick web asymmetric rails in a cost effective manner using the existing productive facility/capacity to the extent possible while maintaining the dimensional accuracy and tolerances and on the other hand also ensure use of such thick web asymmetric rails in combination/matching with the standard symmetric UIC-60 rail sections, making the use and application of such special section rails in wider scale.


OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to provide for thick web asymmetric rails for application in railway track, switches and other like applications, either independently or in combination/matching with standard symmetric rail sections and designing and developing a method for production of such special section rails utilizing existing infrastructure in a cost effective manner ensuring quality and desired characteristics of end products.
Another object of the present invention is directed to developing thick web asymmetric rails for application in railway track, switches and other like applications and process for its manufacture wherein the rolling scheme and roll pass design is developed and rolls are machined for selective grooved profiles so as to ensure desired dimensional accuracy, tolerances and straightness of the finished rail complying to applicable standards/specification.
According to yet another object of the present invention directed to developing thick web asymmetric section rails and its regular production at reasonably low cost to substitute import of such rails and promote export of the good quality rails outside India to thereby result in substantial economic significance with potential for foreign exchange earning.
A further object of the present invention is directed to developing thick web asymmetric rails wherein the head, foot, web, and flange portions of the rail section is having asymmetric distribution/shift of dimensions with respect to the vertical axis.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the method for producing thick web asymmetric rails in rail and structural steel rolling mills wherein rails are being rolled using preferably the diagonal pass design.
A further object of the present invention directed to developing thick web asymmetric rails wherein in the production process, there are 14 passes in all, starting from the bloom to finished rail section comprising selective stages of 7 passes in roughing stands of rolling mill, 3 passes in intermediate stand 1, 3 passes in intermediate stand 2 and 1 pass in finishing stand, to develop the desired thick web asymmetric rail with desired accuracy.

A still further object of the present invention is directed to developing thick web asymmetric rails wherein the rolling stands are configured to be adapted to produce the new variety of thick web asymmetric rail in addition to existing products of R-52 or U1C-60 rails for improved and full plant capacity utilization of rolling mills with higher productivity.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the asymmetric rolls are developed through trial rolling keeping the middle roll as open and top/bottom rolls as closed rolls at 3Hi mill.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the rolls used are turned/machined in such a manner that the working of flange and head are carried out in alternate passes i.e. by diagonal rolling passes.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the metal distribution in each pass ensured that the bar do not get twisted and the load distribution ensured that none of the passes are subjected to overloading in relation to rolling speed.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the process of rolling involved designing a straightening scheme employing head straightening in horizontal plane for straightening of asymmetric thick web rails.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein one end of rail is forged to match with standard UIC-60 profile for track/switch laying matching with existing track.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the finishing table corresponds to the finished length measured for rolled rail.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the area of head and foot of thick web asymmetric rail is adjusted to required measurements by machining.
A still further object of the present invention is directed to developing thick web asymmetric rails wherein the rail head profile is profiled so as to optimize the rail/wheel contact reducing the deflection forces.

SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to thick web asymmetric rail comprising rolled section obtained of rolling involving a middle roll and top and bottom rolls wherein the rolling of the asymmetric section is carried out keeping the middle roll open and the top and bottom rolls closed.
According to another aspect of the present invention is directed to Thick web asymmetric rail obtained involving 14 number of total passes.
A further aspect of the present invention is directed to said thick web asymmetric rail comprising roll formed rail section using selective rolling scheme and roll pass design comprising roughing, intermediate and finish rolling.
According to yet another aspect of the present invention is directed to a process for producing thick web asymmetric rail comprising:
the steps of rolling the asymmetric rail comprising
turning/machining of the rolls for rolling asymmetric rail section adapted such that the working flange and the head carried out in alternate passes favoring attaining desired diagonal rolling and involving a middle roll and top and bottom rolls wherein the rolling of the asymmetric section is carried out keeping the middle roll open and the top and bottom rolls closed and
selectively making the passes for the asymmetric rail keeping in view the metal flow characteristics, elongation coefficients, spread, over/under filling in relation to bar delivery with metal distribution in each said pass of rail made to ensure that the bar do not get twisted during the rolling process and load distribution is maintained such that none of the passes is overloaded in relation to rolling speed.
A still further aspect of the present invention is directed to a process for producing thick web asymmetric rail comprising a total of 14 number of passes wherein the distribution of such passes in different stands comprises

7 passes in roughing stand; 3 passes in first Intermediate stand; 3 passes in second Intermediate stand; and 1 pass in finishing stand.
A still further aspect of the present invention is directed to a process for producing thick web asymmetric rail wherein rolling in roughing stand is carried out in two high reversible stands and the rolling scheme takes care of and prevents the metal getting twisted due to differential distribution of the metal in the bottom and top flanges of the bar and due to asymmetric cutting of the grooves in the bottom roll.
A still further aspect of the present invention is directed to a process for producing thick web asymmetric rail comprising 3 rolling passes in first intermediate stand which is 800 stand I of 3-Hi mill wherein (i) the first pass is a hat pass with special close end at one side of the pass for smooth metal delivery from the pass due to two axially different close ends in one single pass, (ii) the second rolling pass is also a hat pass but having closed end on the top as well as on the side of the pass to restrict the flow of metal, (iii) the third pass is a unique cutting or knifing pass adapted to generate rolled section having two flanges-the top and the bottom flange, a head and a web, thus beginning to form the rail section from the previous hat passes.
A still further aspect of the present invention is directed to a process for producing thick web asymmetric rail comprising said third pass in first intermediate stand wherein said third pass having top flange is open and bottom flange closed, the top head is closed and the bottom head is open and also the top flange length is more than the bottom flange in order to facilitate generating unequal/asymmetric flanges.
A still further aspect of the present invention is directed to a process for producing thick web asymmetric rail comprising rolling in the second stand performed after trial in the first intermediate stand and comprised three passes wherein (i) the fourth pass is having closed top flange and open bottom flange, and also the top head is open and the bottom head is closed;(ii) the fifth pass is having top flange open and bottom flange closed, and also the top head is closed and the bottom head is open; and (iii) the sixth pass is having top flange


closed and the bottom flange open and also the top head is open and the pottom head is closed.
A still further aspect of the present invention is directed to a process for producing thick web asymmetric rail comprising single pass rolling in finishing stand controlling the final dimensions of the rolled profile of the asyrfimetric rail section.
A still further aspect of the present invention is directed to a process for producing thick web asymmetric rail comprising finishing roll pass having top flange as open ^nd the bottom as closed and head is having conventional rail rolling design with roll parting line at the center of tte tead.
The present invention and its objects and advantages are described in greater details with reference to the following accompanying non limiting illustrative figures.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1: is the schematic illustration of the conventional symmetric rail section e.g. R-52 and UJC-60 rails conforming to IRS-T12'2009 symmetric about the vertical axis having equal distribution of the dimension of head, web and flange in linear units with respect to the vertical axis.
Figure 2: shows the flow chart for manufacturing the asymmetric rail following the process of the present invention.
Figure 3: is the schematic illustration of the sequential rolled section shapes generated during rolling of thick web asymmetric rail section through roughing passes of bloom to finishing pass.
Figure 4a-4g: is the detailed schematic illustration of the transformation of thick web asymmetric rail sections according to the present invention in intermediate stands 1 & 2 to finishing roll with machined profile through the successive roll passes no. 1 to 7, in sequence following the rolling scheme, starting with material blank obtained from bloom at output of roughing stand.

Figure 5a-5c: is the illustration of the roller design configuration for the roll pass scheme according to the rolling scheme design of the present invention through the roughing, intermediate and finishing roll stands to provide for the sections of rail in sequential progression corresponding to pass nos. 1 to 7.
Figure 6: is the final section profile of the thick web asymmetric rail according to the present invention obtained by machining of section obtained from the roll pass no. 7 at finish stand, to correct dimension within acceptable tolerances/allowance.
Figure 7: is the schematic illustration of the switch forging to match with existing UIC-60 track sections.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
The present invention relates to thick web asymmetrical rail section and a method of its production and is directed to deciding suitable rolling scheme, roll pass designing and developing said thick web asymmetric rail (Zu 1-60) section to meet the requirements of not only the railway transportation within the country, conforming to the relevant specification but for export to other countries for the appropriate class with desired dimensional accuracy and tolerances and allowance to suit end use/applications.
While the existing symmetric section rails such as the R-52 and UIC-60 rails having head, web and flange distributed in equal linear units with respect to the vertical axis as illustrated in the accompanying Figure 1, the thick web asymmetric rail section has the flange, head and web shifted asymmetrically about the vertical axis. The roll pass design and the rolling scheme followed a diagonal pass design to achieve desired asymmetric rail section at the end of processing.
The thick web asymmetric rail has been developed according to the present invention following the stages of:
a. design of rolling scheme and roll pass design;

b. rolling of asymmetric section on trial basis for the first time using the above rolling
scheme and roll pass design;
c. design of straightening scheme employing head straightening in horizontal plane;
d. setting of pressure triangles at RRSM and use of BS90 VRSM rings;
e. straightening of asymmetric thick web rails.
Reference is now invited to the accompanying Figure 2 that illustrates the flow chart for processing of the asymmetric rail section from bloom to finishing stage. It is clearly apparent from the flow process chart that the bloom is delivered to the roughing stand from the reheat furnaces at 3*75 tons per hour. In the 950 mm roughing stand (roll) stand bloom size of (300mmx335 mm) is reduced in 7 passes to a section size of (155mm x 155mm) for feeding to pass 1 of the three passes in the first intermediate stand. The material is then further rolled in the 800 mm 3-Hi intermediate stands in two stages/stands each having 3 passes to obtain near finish shape of the asymmetric rail section fed to the 850 mm finishing stand. The finished rail section is cut by hot saw to desired lengths on finishing table. The cut to size rail sections then sent to the bi-planar ratt-straightening machine via automatic stamping machine for stamping marks on web and through cooling bed to cool the rails to ambient temperature. The processed and straightened rails are then passed through series of tests for evaluating conformance to desired quality standards e.g. eddy current test, ultrasonic test to detect crack/discontinuity in sections, if any, during forming. The tested rail sections are then sent for carbide sawing and milling to generate finished shape and size/lengths. The finished and straightened rails are inspected for acceptance. Any welding requirement of rails detected during inspection, is carried out for final acceptance before despatch/ storing.
The rolls used in rolling according to the scheme are turned/machined in such a manner that the working of flange and head are carried out in alternate passes and thus deriving the name of diagonal rolling. The trial run for rolling out asymmetric rail has been conducted keeping the middle roll open and top and bottom rolls as closed at the 3-Hi rolling mill. Passes for asymmetric rail are made keeping in view the metal flow characteristics, elongation co-efficient, spread, over/under filing in relation to the bar delivery. Metal distribution for each pass of rail is selectively provided in roll design to ensure that the bar does not get twisted during the rolling process. Reference is invited to the accompanying Figure 3 that illustrate the rail section shapes generated for the


asymmetric rail at different stages of rolling in sequence from roughing stands through the intermediate stands/passes to the finishing pass.
The rolling scheme for developing thick web asymmetric rails according to the present invention, is as follows:
-Total number of passes used are 14, wherein the distribution of passes in different stages comprising:
-7 passes in roughing stand; -3 passes in Intermediate stand 1; -3 passes in Intermediate stand 2; -1 pass in finishing stand.
The details of successive rolled section reduction from the bloom through the 7 passes in the roughing stand are summarized in the following table 1:
Table I:

No. of passes Pass no. Dial Size of metal at output (Input 300x335mm)
IA 1 115 255x
2 65 205x350
TILT 90°
II 3 105 290x
4 45 230x220
TILT 90°
IB 5 55 165x
6 15 125x245
TILT 90°
HI 7 0 155x155


Rolling of the thick web asymmetric rails according to the rolling scheme of the present invention following the diagonal rolling configuration are described for each stage as follows:
a. Rolling in Roughing Stand:
The rolling in roughing stand in rail rolling mill is carried out in Two High Reversible stands. The rolling scheme according to the present invention for rolling thick web rails has been designed and rolling of the blooms carried out in roughing stand accordingly. The roll design and rolling scheme is prepared keeping in view of provisions for rolling of other existing standard rail sections in combination with special thick web rails for achieving maximum roll utilization. Change in passes has been done keeping provisions for parallel processing of UIC-60 kg rail. Finishing pass is newly designed to overcome the problem in rolling at finishing pass of roughing stand due to the asymmetric cutting of the grooves in the bottom roll. There is tendency of the metal getting twisted due to differential distribution of the metal in the bottom and top flanges of the bar when rolled. This problem is solved by modifying the rolling scheme that takes care of the differential distribution of metal in the passes. One bloom has been rolled on trail basis to evaluate the out come of the rolling scheme designed and the delivery has been observed and found that there is no identifiable twisting of the metal coming out of the roughing stand.
b. Rolling in First Intermediate stand:
The rolling in the first intermediate stand is carried out with three-pass scheme in Asymmetric Rail Roll Design in 800 Stand I. The first pass is the hat pass with special close end at the one side of the pass. The problem faced is related to ensuring smooth metal delivery from the pass due to two axially different close ends in one single pass. It involved a new roll pass design for the asymmetric rail .
Reference is now invited to the accompanying Figures 4a- 4g, that schematically illustrate rail section shapes generated progressively through corresponding 7 no. roll passes through intermediate stand-1 and intermediate stand-2 and the finishing stage/rolling stand such that the respective sections are the outcome of rolling of stock obtained at the end of the roughing stand through the respective roll grooves configuration for each of the 7 numbered passes as illustrated in the embodiment of the present invention in Figures 5a-5c respectively.

The second rolling pass is also a hat pass but has closed erid on the top as well as on the side of the pass to restrict the flow of metal. This special design creates some problem during metal delivery from the pass and is overcome by controlling the rolling process parameters.
The third pass is unique in rolling with respect to the asymmetric thick web configuration of the rail section according to the present invention. It is tended as the 'web cutting' or the 'knifing' pass. This pass generates the two flanges-i.e. top and bottom flanges as well as a head and the web and thus generating the basic rail section shape. It is the stage from where the formation of rail begins from the previous hat passes. In conventional roll pass design of standard rails, the top flange is closed and the bottom flange is open to facilitate the working and sizing of the flange dimensions. Also the toP head is open and the bottom head is of close to facilitate the working in the head portion of rail.
Thick web asymmetric rails, in contrast to the conventional practice, having a roll pass design that is unique and new design for the third pass wherein the top flange is open and the bottom flange is closed. Also the top head is closed and the bottom head is of open configuration. These features are clearly identifiable from the accompanying Figures 5a to 5c. Moreover, the top flange length is more than the bottom flange in order to facilitate unequal flanges. This roll passes are carried out in Asymmetric Rail Road Design 800 Stand I wherein pass 3 has a taper of 15% and Runner taper of 20%. The rail section ASR 1 as illustrated in accompanying Figure 4a is obtained at the output of roll pass 1 of Figure 5a as of the first intermediate stand. Similarly, the section shapes ASR 2 and ASR 3 as illustrated in the accompanying Figures 4b and 4c derived from rolling of steel product through the roll passes 2 and 3, as illustrated in Figure 5a, respectively in sequential succession. The semi-finished rail section obtained at the output of Pass 3 as illustrated in Figure 4c is having the approximate dimensions of head width - 115.5 to 116.5mm preferably 116mm; web thickness 67.1 to 68.1 mm preferably - 67.6mm; height - 129.3 to 130.3 mm preferably 129.8mm; and of foot/flange width 199.4 to 201.4mm preferably 200.4mm, which is fed to the next pass 4 in the intermediate stand 2.


c. Rolling in Second intermediate Stand:
The rolling in the second intermediate stand is carried out after conducting trial run in the first intermediate stand. All the three passes are newly configured for the second stand. These passes are carried out in Asymmetric Rail Roll Design 800 Stand II wherein the pass 4 taper is 8%, pass 5 taper is 10%, pass 6 taper is 7% and the Runner taper 20%. The fourth pass is having closed top flange and open bottom flange. The same way, the top head is open and the bottom head is closed. Further, the fifth pass is designed to have top flange open and bottom flange closed. Similarly, the top head is closed and the bottom head is open. The sixth pass is having the top flange closed bottom flange open and in the same way the top head is open whereas the bottom head is closed. In this pass also the rolling tackles are redesigned to cope with the newly configured design passes. The asymmetric rail section as obtained at the end of the sixth pass that is the last pass of the intermediate stand 2, deliver a rail section that is very close to the final shape/dimensions, requiring very small deformation in finishing stage.
ASR 4, 5 and 6 of Figures 4d to 4f, are the section profiles obtained from the roll passes 5, 6 and 7 as illustrated in the rolling scheme for the intermediate stand 2 in Figure 5b. ASR 6 is having a section profile very close in dimensions to that of the final finished shape of the asymmetric rail obtained after finished rolling and machining. It is seen from the accompanying Figure 4f that the asymmetric rail section ASR 6 at the output of pass 6 is having approximate dimensions of head width: 78.1 to 79.1mm preferably 78.6mm, web having thickness 46.5 to 47.5mm preferably 47mm and total height 133.4 to 134.4 mm preferably 133.9mm, foot/flange having width 150.3 to 151.3mm preferably 150.8mm. This rail section is fed to the pass no. 7 in finishing roll stand to generate final rolled shape of the thick web asymmetric rail.
d. Rolling in the Finishing Stand:
The rolling in finishing stand plays an important role as it controls the final dimensions of the rolled profile. In the finishing stands, both the entry and the delivery guides are fitted using cast iron insert plates so as to avoid scratch marks on the surface of rail. Also, the Guards of more width are used to avoid delivery of twisted bars at the exit from this final pass. The finishing pass is of unconventional rail roll design having top flange as open and the bottom as closed. The head design is same as in conventional rail rolling i.e. the top

head is open and the bottom head is of close. The roll parting line is maintained at the center of the rail head. The final section obtained as ASR 7 at the output of Pass 7 in the finishing Stand is illustrated in the accompanying Figure 4g, obtainable from the rolling pass 7 in Asymmetric Rail Roll Design 850 Stand 3 as illustrated in the accompanying Figure 5c, where surface unevenness appear in the roll parting line at the center of rail head. This is machined to give smooth profile of rail head and other flange/foot dimensions of asymmetric rails are machined to arrive at the specified limits based on applicable RDSO specification as illustrated in the accompanying Figure 6.
TESTING AND APPROVALS:
The rail sections so produced are subjected to different testing and quality checks to comply with the requirements of inspection agencies like the RITES or the RDSO for evaluation of its suitability for own use/application by the Railways. Results of several other applicable tests comprising the Falling weight test, chemical, tensile, macro analysis are found satisfactory by the inspection agencies. The rails rolled on trial basis have been inspected for dimensions, profile and surface finish using certified check gauges, eddy current and ultrasonic tests for fault detection and found to meet the requirements of the railway application as per applicable standards/design and the thick web asymmetric rail section produced on trial basis, and in particular, a sample of asymmetric rail of 1.5 meter length has been approved by RDSO. Also, the in-house test facility of the applicants available at the Research and Development Center for Iron and Steel (RDCIS) conducted measurements of residual stresses in rolled asymmetric rail section and found it within limits.
FURTHER PROCESSING OF THE ASYMMETRIC RAIL SECTION OBTAINED FROM FINISH ROLLING
A. FORGING:
One end of the thick web asymmetric rail produced following the process steps and rolling scheme as well as the roll pass design according to the present invention is subjected to forging operation to match with the UIC-60 end profile. An example of this may be seen in Switch Forging as illustrated in accompanying Figure 7. The finishing

table corresponds to measurement of the standard rolled rail section dimension/length at finishing pass. This post-processing of asymmetric rail section enable use of the thick web rails in combination with existing UIC-60 rail sections/switches, with desired matching at connecting joints.
B. MACHINING/MILLING:
The as rolled section of the thick web asymmetric rail having permissible allowances on over all dimensions, are subjected to machining/milling operation in order that the area of head and foot/flanges is adjusted to desired dimensions by machining preferably by milling, depending on specific applications.
C. SWITCH FABRICATION:
The typical application of thick web asymmetric rails obtained by way of the present invention includes fabrication of Switches used for changing tracks for railway carriages. The fabrication process involve machining of the web/flanges to match with existing rail track sections while ensuring enhanced operating life for the switches because of the typical section profile of such thick web rails having inherent higher strength. Importantly, while carrying out the required machining of the web/flanges of the thick web rails used for fabrication of the switches, rail/wheel contact at switches is optimized by selective profile machining to thereby reducing the deflecting forces while a railway carriage is changing track.
It is thus possible by way of the present invention to developing a thick web asymmetric rail section and a method of its production by implementing selective roll pass design and selective rolling scheme to convert bloom to finished thick web asymmetric rails for a number of application and use in railway transportation e.g. railway points and crossings, switch fabrication and the like. Importantly, the rolling scheme and roll pass design according to the present invention comprising the roughing passes, the intermediate passes and the finishing pass adapted to convert blooms to desired asymmetric rail section by successive section reduction in each pass to achieve the desired dimensional accuracy with specified rolling tolerances and desired levels of straightness through trial run conducted to conform to applicable railway standards. Thus the thick web asymmetric rails on one hand are value added products developed

by utilizing the in-house facilities and expertise, and on the other hand adapted to economizing the cost of production and more importantly said asymmetric rails capable of import substitution and cater to the export markets and thus having significant economic impact. The roll pass design involving a total of 14 passes comprising 7 roughing pass, 3 passes in intermediate stand-1, and 3 passes in intermediate stand 2 and 1 finishing pass, to convert the bloom section to the asymmetric rail section. The rail section is further forged and/or machined to match with the existing standard UIC-60 tracks with the one end of asymmetric rail forged to a profile having nearly same dimensions for desired matching. Advantageously, the rails are machined to suit switch fabrication with reliable performance and optimized rail/wheel contact for reduced deflecting force during change of track on motion. The thick web asymmetric rails according to the present invention is a low cost solution to meet the import substitution and export needs in the related field and ensure reliable performance for various railway track & traffic application with longer operating life while having the flexibility of being used in combination with existing convention standard track configuration.


We Claim:
1. Thick web asymmetric rail comprising rolled section obtained of rolling involving a middle roll and top and bottom rolls wherein the rolling of the asymmetric section is carried out keeping the middle roll open and the top and bottom rolls closed.
2. Thick web asymmetric rail as claimed in claim 1 obtained involving 14 numbers of total passes.
3. Thick web asymmetric rail as claimed in anyone of claims 1 or 2 comprising roll formed using selective rolling scheme and roll pass design comprising roughing, intermediate and finish rolling.
4. A process for producing thick web asymmetric rail as claimed in anyone of claims 1 to 3 comprising:
the steps of rolling the asymmetric rail comprising
turning/machining of the rolls for rolling asymmetric rail section adapted such that the working flange and the head carried out in alternate passes favoring attaining desired diagonal rolling and involving a middle roll and top and bottom rolls wherein the rolling of the asymmetric section is carried out keeping the middle roll open and the top and bottom rolls closed and
selectively making the passes for the asymmetric rail keeping in view the metal flow characteristics, elongation coefficients, spread, over/under filling in relation to bar delivery with metal distribution in each said pass of rail made to ensure that the bar do not get twisted during the rolling process and load distribution is maintained such that none of the passes is overloaded in relation to rolling speed.
5. A process for producing thick web asymmetric rail as claimed in claim 4 comprising a
total of 14 number of passes wherein the distribution of such passes in different stands
comprises


7 passes in roughing stand; 3 passes in first Intermediate stand; 3 passes in second Intermediate stand; and 1 pass in finishing stand.
6. A process for producing thick web asymmetric rail as claimed in anyone of claims 4 to 5 wherein rolling in roughing stand is carried out in two high reversible stands and the rolling scheme takes care of and prevents the metal getting twisted due to differential distribution of the metal in the bottom and top flanges of the bar and due to asymmetric cutting of the grooves in the bottom roll.
7. A process for producing thick web asymmetric rail as claimed in anyone of claims 4 to 6 comprising 3 rolling passes in first intermediate stand which is 800 stand I of 3-Hi mill wherein (i) the first pass is a hat pass with special close end at one side of the pass for smooth metal delivery from the pass due to two axially different close ends in one single pass, (ii) the second rolling pass is also a hat pass but having closed end on the top as well as on the side of the pass to restrict the flow of metal, (iii) the third pass is a unique cutting or knifing pass adapted to generate rotted section having two flanges-the too and the bottom flange, a head and a web, thus beginning to form the rail section from the previous hat passes.
8. A process for producing thick web asymmetric rail as claimed in anyone of claims 4 to 7 comprising said third pass in first intermediate stand wherein said third pass having top flange is open and bottom flange closed, the top head is closed and the bottom head is open and also the top flange length is more than the bottom flange in order to facilitate generating unequal/asymmetric flanges.
9. A process for producing thick web asymmetric rail as claimed in anyone of claims 4 to 8 comprising rolling in the second stand performed after trial in the first intermediate stand and comprised three passes wherein (i) the fourth pass is having closed top flange and open bottom flange, and also the top head is open and the bottom head is closed;(ti) the fifth pass is having top flange open and bottom flange closed, and also the top head is closed and the bottom head is open; and (iii) the sixth pass is having top flange closed and the bottom flange open and also the top head is open and the bottom head is closed.


10. A process for producing thick web asymmetric rail as claimed in anyone of claims 4 to 9 comprising said second intermediate stands comprised modification of rolling tackles that are configured to cope with the new design of passes.
11. A process for producing thick web asymmetric rail as claimed in anyone of claims 4 to
10 comprising single pass rolling in finishing stand controlling the final dimensions of the
rolled profile of the asymmetric rail section.
12. A process for producing thick web asymmetric rail as claimed in anyone of claims 4 to
11 comprising finishing roll pass having top flange as open and the bottom as closed and
head is having conventional rail rolling design with roll parting line at the center of the head.
13. Thick web asymmetric rail rolled section adapted to suit various railway track application
especially in switch/points fabrication and process for its production substantially as here in
described and illustrated with reference to the accompanying non limiting illustrative
figures.