Title of Invention

A METHOD OF MANUFACTURING RAILWAY RAIL WITH REINFORCED HEAD

Abstract The rail, according to the invention, preferably of "grooved rail" type, comprises, as a direct result of the rolling of a semi-finished product coated on its face intended to form the grooved (8) with a layer (23) of wear-resistant material, a coating consisting of the said material and continuously covering at least the active surface (7) of the running table (6) of the head (3) and rolling corner (13) and preferably also the fillet radius (16) connecting the outer side wall (10) of the grooved (8) to the lateral lip (11). Such a rail is preferably used for producing railway lines for transporting vehicles in an urban environment, such as tramways or light metropolitan railways, and in which there is a desire to reduce the wear and the nuisance caused by noise.
Full Text
FORM 3 A
THE PATENTS ACT, 1970 COMPLETE SPECIFICATION
(See Section 10)


A METHED MANUFURING

A METHOD OF MANUFACTURING RAILWAY RAIL WITH
REINFORCED HEAD

SOGERAIL of 164 RUE DU MARECHAL FOCH, 57705 FRANCE, FRENCH Company

- HAYANGE,

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed : -


667
1998



A METHED OF MANUFACTURING RAILWAY RAIL WITH REINFORCED HEAD
The present invention, which relates to the field of transport, deals with railway rail, more particularly a grooved rail.
Grooved rails of the type in question are rails intended to be
buried and which are used essentially in an urban environment for
supporting and guiding urban railway vehicles, such as the
tramway or light metropolitan railways.

It is recalled that the head of a grooved rail of the type of the invention comprises a running table intended to support the wheeled vehicle and which adjoins a guide groove which accomodates the flange of the wheel, this groove being bordered by a lip which acts as a lateral slideway in curves and prevents soil from burying the groove.
It is known that the use of buried rails in urban environments poses two particulary acute problems which exist as a general rule in rail transport: these are the problem of noise and the problem of rail wear which may, incidentally, itself cause acoustic nuisance.
The problem of noise affects aspects associated with the comfort of those living or working alongside the track and to which partial solutions have already been attempted or are to be tackled in greater depth, particularly in terms of anti-noise or

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anti-screech coating of the surfaces which are in contact with each other during running.
The problem of rail wear is of a far more technical nature, because it unavoidably leads to the transport line being taken out of service if appropriate solutions are not found.
As can be seen, a distinction can be made between two types of wears the " curve wear" which occurs on the edges of the groove as a result of the lateral thrust from the wheel flanges in tight curves and which, under extreme conditions, can cause derailment, and so-called "corrugation" wear, the exact mechanisms governing the formation of which are still only partially understood. The phenomenon of wear with corrugation, which above all is characteristic of journeys with frequent stopping and starting inherent to urban transport mainly affects the running surface in contact with the wheel tyres. It can cause damage to the chassis of the vehicles, and also be the cause of noise produced by wheel vibration.

As described, for example, in SB No. 5918 (A.D. 1911), the usual solution consists in removing material from the new rail by machining the surface in the most vulnerable regions which are the top of the running surface where contact with the wheel tyre occurs and the rolling corner of the rail head, namely, in the particular case of grooved rails, the fillet radius where the
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groove meets the running surface on one side and the lip on the other. Next, the regions are sacrificially built up by welding using a reinforcing material, therefore, one which is more resistant than the steel of the rail (conventionally a C—rNi alloy containing Mo) A further grinding operation is then needed to return the rail to its nominal profile before it is laid as a track. During use, the rail is regularly built up again and ground at these points in order to compensate for the loss of reinforcing material through wear due to friction.
The advantage of the method is that it is not necessary to remove the buried rail in order to recondition it. However, its cost is obviously very high or even prohibitive. Furthermore, a heat-affected zone (HAZ) inherent to any welding operation is inevitably created, and this makes a final reheat operation necessary in an attempt to restore the mechanical properties which, in any case, are difficult to achieve because of the relatively high carbon content of the steel of which rails are usually made. What is more, welding and reheating inevitably creates deformations of a thermal origin which, given the fairly complicated geometric shape of the head of grooved rails, are difficult to recover even by a further rail-straightening operation.
The object of the present invention is to/provide a solution to the problem of rail wear, particularly grooved-rail wear which

gets around the drawbacks of the known aforesaidmentioned remedies.


To this end, the subject of the invention is a railway rail, the head of which is reinforced against wear and characterized in that, in order to reinforce the head, the rail is obtained, using the rolling process that is usual for railway rails, directly by rolling a metallurgical semi—finished product, advantageously made of a bloom from continuous casting, which has one face covered with a reinforcing material, at least over part of its width, the said face being the one intended to form the head during the rolling, and in that the said part-finished product comprises, in the rolled state, a continuous layer made of the said reinforcing material which extends over the entire length of the rail and completely covers the width of the running table and its rolling corner.
As a preference, the subject of the invention is a grooved rail intended to be buried so that it can be used in an urban environment for transporting and guiding railway vehicles such as tramways or light metropolitan railways, and the wear—reinforced head of which comprises a running table, a lateral lip and, between these, a guide groove with the edge of its side wall formed of fillet radious with the running table (the rolling corner) on the one hand and the lateral lip on the other hand, this grooved rail being characterized in that, in order to
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reinforce the head, the rail is obtained directly by rolling using the usual process for rolling grooved rails, a metallurgical semi-finished product, advantageously a bloom from continuous casting, and which has one face covered with reinforcing material, at least over part of its width, the said face being the one intended, during rolling, to be cut to produce the groove, and in that it comprises, in the rolled state, a continuous layer formed by the said reinforcing material which extends over the entire length of the rail and completely covers the width of the running table and rail rolling corner.
As a preference, the fillet radious where the groove meets the lateral lip is also coated with a continuous layer of the said reinforcing material.
Also as a preference, the layer of reinforcing coating has a thickness which decreases from the rolling corner-As will be understood, the solution proposed by the invention consists in producing the reinforced rail directly by rolling. There is thus obtained by rolling a rail ready for use with reinforcing materials where they are needed, with the correct profile and the correct straightness without requiring further operations, and without a heat-affected zone (HAZ) because the reheat prior to rolling eliminates from the coated semi-finished product to be rolled the HAZ that might have been created when

the reinforcing material was being added. Similar techniques are, in any case, already indicated for adding an anti-corrosion coating to the rails of little-used railway lines (for examples FR 2 697 452).
Another subject of the invention is a method for manufacturing such a railway rail, in which method the rail is rolled from a metallurgical semi-finished product of rectangular section made of rail steel, characterized in that a layer of reinforcing material is applied to one face of the said semi-finished product and covers it completely, then the said semi-finished product is rolled in the way usually used for rolling a grooved rail, but performing the operation of forming the head on the coated face.
As a preference, the bare semi-finished product is a bloom from continuous casting.
The layer of reinforcing material can be applied to one face of the bare semi-finished prodcut in various ways, for example, by building-up in the hot state using, a molten filler metal, by welding on a strip, by co-rolling the semi-finished product with such a strip, or by any other known or forthcoming technique which makes it possible to obtain a composite semi-finished product formed of the superposition of a rail-steel bloom with a single-sided surface layer of a material which resists frictional wear, such as an Ni-Cr—Mo alloy, for example. and which is

already known and used for the same purposes.
The invention will be well understood and other aspects and advantages will emerge more clearly in the light of the description which follows, given by way of non-limiting example, with reference to the appended plate of drawings, in which
Figure 1 depicts, viewed in cross-section, a finished grooved rail ready for use in accordance with the invention;
Figure 2 is a functional diagram depicting the stages in a method for manufacturing a grooved rail according to the invention-
Figure 1 shows the profile of a grooved rail with its foot i, its vertical web 2 which ends in a head 3. This head contitutes the active part of the rail because it is intended to corns into contact with the wheels of the railway vehicle (not depicted) placed on top of the it once the railway line has been constructed from a parallel twin row of rails according to Figure 1 placed end to end. Such a railway line is conventionally buried in the ground 4 up to a level 5 which leaves the head 3 even with the ground.
This head is itself conventionally made up of three functional parts juxtaposed from left to right in the figure: first of all the running table 6, the top 7 of which constitutes the active
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surface of the rail and is in loaded contact with the wheels of the support vehicle, next, the groove 8 which is intended to accomodate the wheel flange for guiding it in curves by butting against its sids wall 9 and 10, and finally the lip 11 which acts as an anti-derai-lment lateral sideway by means of its inner side wall 10, and as a partition which prevents the groove 8 from becoming buried.
The head 3, the? web 2 and the foot 1 are usually obtained as a
single piece by rolling a bloom of rail steel from a continuous
casting machine producing blooms or slabs to be spilt down into
b1ooms.
As can be seer the running table is coated with a layer 12, originating from the rolling of the rail, made of a material that resists frictitional wear, such as molybdenum-doped , nickel-chrome-based alloy, or such as an austentic steel. The thickness of the layer 12 is preferably at least 2mm at the most heavily loaded point whith is the rail rolling corner 13 where the inner side wall 9 of the groove 8 meets the top of the running table 6.
This layer may be of constant thickness across the entire table 6. It may also and preferably, decrease gradually from the rolling corner 13 on each side thereof, as far as the outer edge 14 of the running table and along the side wall 9 of the groove. In any event, it is essential that should be continuous therfore
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without uncovered regions, even local ones, along the entire width of the active surface 7 of the head and extend towards the bottom of the groove on the inner side wall 9 thereof, covering the rolling corner 13 of the rail.
As a preference, as can be seen in Figure 1, the side wall 10 of the groove, which is formed on the lip 11, may also have its top edge covered with a layer 15 of reinforcing material of constant thickness or progressive thickness starting from the fillet radious 16 where the groove meets the lip.
It will be seen with reference to figure 2 how the layers 12 and 15 jointly originate from the same initial layer on the semi-finished product to be rolled, from which they result directly from the rolling, whereas the bottom 17 of the groove itself becomes devoid of any reinforcing coating, something which proves to be an economic advantage through the saving of material because an anti-water reinforcement at this point would prove unnecessary.
Referring now specifically to Figure 2, the main stages in the continuous manufacture of a rail in accordance with the invention can be followed chronologically.
A bloom 20 made of the usual steel employed for railway rails comes from a continuous casting installation 21 and is directed
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into a coating station 22 so as to be covered on one face with a layer 23 of an anti-wear reinforcing material (Mo-doped Ni.Cr alloy for example). After heating in a furnace 24 for bringing it up to its rolling temperature, the semi-finished product 20-23 from the station 22 is rolled in a roll mill 25 of the usual type employed when manufacturing grooved rails. The grooved rail 26 obtained is then brought down to room temperature by soaking in a cooler 27, before being cold-straightened in a straightener 28 which makes sure that the product is straight. The product then undergoes quality control in an inspection unit 29 before completing its manufacturing process in a finishing station 30, where, in particular, it is cut to length and holed at the appropriate points so that it can then be put together as a track.
It will be noted that the roll train 25 is a train entirely in accordance with those conventionally used or usable for rolling grooved rails, namely a train in which the successive roll stands are equipped with fluted rolls, which progressively impart to the blank passing through the nips of the roll stands the final profile desired in terms of shape and size.
Care will, however, be taken that the coated bloom 20-23 is oriented, as it enters the rolling mill 25, in such a way that the groove-forming operation (known as "cutting pass") which takes place by one face of the blank being indented using rolling
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rolIs which have a rim for this purpose, does indeed take place on that face of the semi-finished product which is covered with the reinforcing layer 23.
This covering is performed, as already stated, in the coating station 22. Various techniques of application are possible, such as explosion, co-rolling a filler strip with the bare bloom to be coated, metallization by spraying on to the face to be coated, building up this face by arc-welding flat barstock or filaments of a reinforcing material placed next to one another along the width of the face to be covered. Any technique of coating with metal may, in this regard, be suitably provided, as already mentioned, it allows the entire face of the part-finished product to be rolled, or just part of its width, to be coated with a continuous layer 23.
By way of trials, which proved conclusive, this coating was performed by hot build-up using filaments of austenitic steel deposited and arc-welded until, by the spreading of the material, they formed a constant layer covering the entire face concerned of the bloom to be rolled.
It is useful to emphasize, at this stage of the explanation, the two essential aspects underlying the industrial feasibility of a grooved rail with a head coated in accordance with the invention; the effect of the "face cutting" to form the groove, and the
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possibility of having a continuous initial coating layer 23 on the part-finished product to be rolled which is of a thickness that varies across the width of the face to be covered.
It was actually discovered that it was the "cutting pass" operation itself which naturally allowed the initial layer 23 to be split into two zones, each continuous but separated from the Dther on the finished product, one of these zones 12 covering the running table 6 and the rolling corner 13, and the other, 15, covering the fillet radius 16 running into the lip 11, and that this was achieved while at the same time creating a groove bottom 17 which was free of any coating (which coating would be superfluous there), whereas this point, over which the rib of the rolling rolls is positioned, was, however, initially covered.
dhat was more, it was possible to demonstrate that this point of the coated face of the semi-finished product to be rolled not anly needed to be covered in order to ensure the aforementioned desired end result, but that it needed to be covered with a thickness of layer that was preferably higher there than elsewhere. It was thus possible, through this specific measure alone, to obtain on the finished rail a thickness of reinforcing layer which was greater on the rolling corner 13 and fillet adius 16 (the places subject to the heaviest wear in curves) and bhinning gradually away from these corners.
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In other words, it will be advantageous to adopt a technique of coating with metal, current or to come which, following the example of the one already mentioned that employs building-up by welding on filaments or flat barstock, makes it possible to produce initial layers 23 of thicknesses that can vary across the width of the face that is to be covered.
It goes without saying that the invention is not restricted to
the embodiment described hereinabove but that it extends to
numerous alternative or equivalent forms insofar as its
definition given by the following claims is respected.
In particular, the coating layer 23 may be on just part of the face to be covered so that only the active surface 7 of the finished rail is reinforced. Here too, the technique of building up by welding seems well suited.
Likewise, numerous alloys may be suitable for forming the reinforcing material. As a preference, use will be made of austenitic steels, or ferrous or non-ferrous alloys containing, by weight, at least 107. of Cr or of Ni of Mn, or of a combination of these three totalling at least the 10"/. by weight, and also containing Mo in a quantity by weight of 3% at the most, or conventionally of between_0.57. and 17..
Likewise too, the term "reinforcing layer" must be understood as
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meaning at least one layer, it being understood that it would
actually, be perfectly feasible for the face concerned of the
semi-finished product to be rolled to be coated with several
superimposed layers of different materials, or with a single
layer but with a gradient of properties according to its
thickness.
It will also be recalled that, although the invention was designed initially for grooved rails, it nonetheless remains applicable also to the "T" rails of conventional railroad tracks; the rail head of which is simply formed of a running table bordered on each side by a rolling corner, and on one or other of which the wheel flange rubs in curves, depending on whether the curve bends to the right or to the left.
Apart from the top of the running table which will be reinforced, the reinforcing layer will then preferably cover both rolling corner and fillet radius so that the rail can be placed just as easily in either the left-hand line or the right-hand line when the track i© being laid. However, it is possible to restrict the coating to just one of said parts, if the symmetry of the geometric shape of the rail allows its sense to be reversed when laying it as a track.
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WE CLAIMS :
1. A method of manufacturing a Railway rail with reinforced head comprising the grooved rail being characterized in that, in order to reinforce the head (3) , the rail is obtained directly by rolling, using the usual process for rolling grooved rails, a semi-finished product (20) which has one face covered with a reinforcing material (23) , at least over part of its width, the said face being the one intended, during rolling, to be cut to produce the groove (8) of the rail, and in that it comprises, in the rolled state, a continuous layer (12) formed by the said reinforcing material and which extends over the entire length of the rail, completely covering the width of the active surface (7) of the running table (6) and the rolling corner (13).
2. A method of manufacturing a railway rail as claimed in claim 1 wherein the lateral lip (11) is also coated with a continuous layer (15) of reinforcing material on the fillet radius (16) where it meets the outer side wall (10) of the groove (8).
3. A method of manufacturing a railway rail as claimed in claim 1 & 2 wherein the coating (12, 15) has a thickness of at least 2 mm both at the rolling corner (13) and the fillet radius (16).
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4. A method of manufacturing a railway rail as claimed in claim 1 to 3 wherein the running table (6) has a layer (12) of reinforcing material, the thickness of which decreases from the rolling corners (13, 14).
5. A method of manufacturing a railway rail as claimed in claim 1 wherein the reinforcing material of which the coating is made contains at least 10% by weight of one or more elements chosen from Cr, Ni and Mn, and at most about 3% of Mo.
6. A method of manufacturing a railway rail as claimed in claim 1 wherein the semi-finished product (20) from which it is made is a bloom obtained by continuous casting.
7. A Method of manufacturing a railway rail according to Claim 1, in which the rail is rolled from a mettalurgical semi¬finished product of rectangular section, characterized in that a layer (23) of reinforcing coating which at least partially covers one face of the semi-finished product (20) to be rolled, and does so continuously, is deposited on the said face and then the semi-finished product thus coated is rolled in the way usually employed of rolling railway rails, but performing the operation of forming the head on the said coated face.
8. A Method of manufacturing a railway rail as claimed in Claim 7, characterized in that a layer (23) of coating, the thickness of which varies across the width of the face, is deposited on one face of the semi-finished product (20).

9. A Method of manufacturing a railway rail as claimed in Claim 7, characterized in that the layer (23) is deposited on one face of the semi-finished product (20) by co-rolling a strip with the said semi-finished product (20) or by building-up by welding filaments or flat barstock onto the said one face.
Dated this 16th day of October, 1998
HIRAL CHANDRAKANT JOSHI AGENT FOR SOGERAIL
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Documents:

667-bom-1998-abstract(16-10-1998).pdf

667-bom-1998-affidavit(17-11-1998).pdf

667-bom-1998-cancelled pages(14-5-2003).pdf

667-bom-1998-claims(16-10-1998).pdf

667-bom-1998-claims(amended)-(11-2-2003).pdf

667-bom-1998-claims(amended)-(14-5-2003).pdf

667-bom-1998-claims(amended)-(7-4-2003).pdf

667-bom-1998-correspondence(14-5-2003).pdf

667-bom-1998-correspondence(ipo)-(25-4-2003).pdf

667-bom-1998-description(complete)-(16-10-1998).pdf

667-bom-1998-drawing(16-10-1998).pdf

667-bom-1998-form 1(16-10-1998).pdf

667-bom-1998-form 2(16-10-1998).pdf

667-bom-1998-form 2(title page)-(16-10-1998).pdf

667-bom-1998-form 3(6-2-2002).pdf

667-bom-1998-form 4(16-11-1998).pdf

667-bom-1998-form 4(17-4-2003).pdf

667-bom-1998-form 6(28-10-1998).pdf

667-bom-1998-general power of attorney(5-11-1998).pdf

667-bom-1998-specification(amended)-(14-5-2003).pdf

abstract1.jpg


Patent Number 248257
Indian Patent Application Number 667/BOM/1998
PG Journal Number 26/2011
Publication Date 01-Jul-2011
Grant Date 30-Jun-2011
Date of Filing 16-Oct-1998
Name of Patentee SOGERAIL
Applicant Address 164 RUE DU MARECHAL FOCH, 57705-HAYANGE,
Inventors:
# Inventor's Name Inventor's Address
1 SOGERAIL 164 RUE DU MARECHAL FOCH, 57705-HAYANGE,
PCT International Classification Number E01B009/44
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 97 13202 1997-10-20 France