T 0224/05 31-01-2008

I. The patent proprietor lodged an appeal against the decision of the Opposition Division to revoke European patent No. 0 612 852.

II. Two oppositions were filed against the patent in its entirety under Article 100(a) EPC (opponents I and II), for lack of novelty and inventive step, and under Articles 100(b) and 100(c) EPC (opponent II), that the patent does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by the person skilled in the art and for extending beyond the content of the application as originally filed.

The Opposition Division held that claim 1 of the single request dated 11 June 2003 (which contained only linguistic printing error corrections compared to claim 1 as granted) met the requirements of Rule 88 EPC, of Article 123(2) EPC and of Article 100(b) EPC. The later filed document E21 was considered to be relevant and thus introduced into the proceedings. The Opposition Division further considered that the subject-matter of claim 1 of the single request was novel, particularly with respect to E2, E3, E4, E5 and E21. The subject-matter of claim 1, however, was considered to lack an inventive step with respect to a combination of either E9 or E20 with E21.

III. With a communication accompanying the summons to oral proceedings dated 19 November 2007 the Board presented its preliminary opinion based on claims 1 to 3 of the main request, and claims 1 to 3 of the auxiliary requests 1 to 5, all as filed with the grounds of appeal dated 12 May 2005.

The Board gave its preliminary opinion that the request for correction of claim 1 of the main request did not appear to be allowable as a request under Rule 88 EPC 1973 (as of 13 December 2007: Rule 139 EPC) since there was no error in the document filed at the EPO. The errors were printing errors for which the Examining Division is responsible and if the patent is maintained amended then these printing errors no longer arise. Furthermore, the subject-matter of claim 1 of each auxiliary request appeared to extend beyond the content of the application as originally filed and thus to contravene Article 123(2) EPC.

With respect to novelty of claim 1 of the main request the Board remarked that it neither specifies that only the rail head surface is cooled (so that it appeared to cover also the case wherein the whole rail is cooled such that the entire cross-section should reveal an essentially uniform structure) nor that a specific bainite structure, namely lower bainite, is obtained.

Claim 1 of the main request only requires that the head of a hot rail having a certain composition is cooled from the austenite temperature region with a cooling rate of 1-10ºC/sec to a specific cooling stop temperature of from 500-300ºC and then further cooled according to features f1) or f2).

With respect to the alternative f1) it has to be considered that there will always be a temperature gradient between the centre of the rail and its surface when the surface of the rail is cooled which only will be zero when the entire rail eventually has reached the temperature of the surrounding medium.

Therefore with respect to E21 it needed to be discussed whether this can be the case within a period of 900 seconds or 780 seconds according to the embodiment described at column 7, lines 50 to 60 and whether or not this implies that the condition of feature f1), i.e. that the surface of the rail head is heated to a temperature of not more than 150ºC above the temperature reached on completion of the accelerated cooling is fulfilled. It appeared that the cooling rate for this embodiment according to E21 should be considered to be at least 1.3ºC/sec in the forced cooling step whereas there will be natural cooling of the rails at point H after the fluidised bed treatment. Hence it seemed that claim 1 of the main request might lack novelty provided that the temperature gradient/rail head surface heating question is answered positively (compare Case Law of the Boards of Appeal of the European Patent Office, 5th edition 2006, section I.C.4.2.2).

The Board then remarked that provided that novelty would be acknowledged the issue of inventive step would be dealt with for all formally allowable requests taking into consideration the problem-solution approach.

It should be discussed whether E9 or E20 represented the closest prior art for claim 1 - and taking account of the problem to be solved, which will be based on the effect of the distinguishing features - it will be discussed whether or not the available prior art, particularly E9, E20 and E21, renders the subject-matter claimed obvious, particularly when considering the common general knowledge of the skilled person, e.g. with respect to the TTT-diagrams for rail steels. In this context it should also be discussed whether E21 represents a non-enabling disclosure as argued by the appellant and whether or not the skilled person would modify the known bainitic steel rails in a specific manner in order to improve some properties of the rails using a specific heat treatment process in order to obtain an improved bainitic structure.

The Board also remarked that neither respondent had defined an objective problem with respect to E20 as the closest prior art and that if necessary the combination of E20 and E21 should also be discussed.

The parties were given the opportunity to file observations to the communication which should be filed well in advance, i.e. at least one month, before the date of the oral proceedings.

Finally, the parties were advised to take note of the RPBA, in force as of 1 May 2003 and especially of Article 10b (as of 13 December 2007: Article 13).

IV. With letter dated 19 December 2007 the appellant (patent proprietor) filed an amended main request and auxiliary requests 1 to 9 replacing its previous requests in combination with arguments concerning the basis of the amendments and the patentability of the respective requests. Annexes C to E were also submitted with the same letter.

V. With letter dated 20 December 2007 the appellant submitted Annex F.

VI. With letter of 21 December 2007 respondent II submitted arguments with respect to the amended requests of the appellant.

VII. Respondent I submitted further arguments together with an annex A with its letter dated 28 December 2007.

VIII. With letter dated 17 January 2008 the appellant submitted further arguments as response to the submissions of the two respondents.

IX. Oral proceedings before the Board were held on 31 January 2008. Auxiliary request 1 was withdrawn by the appellant during the oral proceedings.

(a) The appellant requested that the decision under appeal be set aside and that the patent be maintained in amended form on the basis of the main request or alternatively on the basis of auxiliary requests 2 to 9, all as filed with letter dated 19 December 2007, or alternatively on the basis of auxiliary requests 10 and 11 as filed during the oral proceedings.

(b) The respondents (opponent I and opponent II) each requested that the appeal be dismissed.

(c) During the oral proceedings the following documents were discussed:

E1 = GB-A-1 450 355

E2 = Atlas zur Wärmebehandlung von Stählen, Vol. 1, page 105

E5 = ETR (1989), No.12, December pages 775-481

E9 = Tech. Mitt. Krupp, Werksberichte, Vol. 37(1979), No. 3, pages 79-87

E20 = Bainite in Steels, 1992, pages 378-387

E21 = DE-A-1 533 982 (and its patent family member E21a = GB-A-1 131 662)

Annex F = M. Ueda et al., "Development of Bainitic Steel Rail with Excellent Surface Damage Resistance", IHHA'99 STS-Conference, Session 3, Contributed Papers, Sub-Session 3.2, pages 259 to 266

At the end of the oral proceedings the Board announced its decision.

X. Claim 1 of the main request reads as follows (amendments compared to claim 1 as granted with deletions put between brackets are in bold; emphasis added by the Board):

"1. A process for manufacturing high-strength bainitic steel rails with an excellent rolling-contact fatigue resistance comprising the steps of hot-rolling steels consisting of 0.15 % to 0.45 % carbon, 0.15 % to 2.00 % silicon, 0.30 % to 2.00% manganese, and 0.50 % to 3.00 % chromium, and optionally at least one element selected from a first group consisting of 0.10 % to 0.60 % molybdenum, 0.05 % to 0.50 % copper and 0.05 % to 4.00 % nickel, a second group consisting of 0.01 % to 0.05 % titanium, 0.03 % to 0.30 % vanadium, and 0.01 % to 0.05 % niobium, and a third group consisting of 0.0005 % to 0.0050 % boron the remainder consisting of iron and unavoidable impurities, subjecting the head of an as-rolled rail still hot or of a rail heated to a high temperature to an accelerated cooling from the austenite region to a cooling stop temperature of 500º to 300º C at a rate of 1º to 10º C per second, and then [either] heating the rail head surface of the rail head to a temperature not more than 150º C above the temperature reached on [g]completion of the accelerated cooling by means of heat recuperation from the interior of the rail, and then naturally cooling to a lower temperature zone [, or cooling the rail head subjected to the accelerated cooling to the vicimity of room temperature at a rate of 1º to 40ºC per mimute]."

XI. Claim 1 of auxiliary request 2 differs from claim 1 of the main request in that the additional feature "at which the bainite transformation is not completed" has been inserted between the wording "temperature of 500º to 300ºC" and "at a rate of 1º to 10º per second".

XII. Claim 1 of auxiliary request 3 differs from claim 1 of auxiliary request 2 in that the additional feature "by using air, mist or an air-atomized liquid from nozzles disposed on both sides of the rail head" has been inserted between the term "at a rate of 1º to 10ºC per second" and the term "and then heating the rail head surface …".

XIII. Claim 1 of auxiliary request 4 differs from claim 1 of the main request in that the feature "by using air, mist or an air-atomized liquid from nozzles disposed on both sides of the rail head" has been inserted between the term "at a rate of 1º to 10ºC per second" and the term "and then heating the rail head surface …", and that as second feature ", wherein the rail has a hardness of Hv 300 to 400 in the center of the rail head surface and a minimum of Hv350 in the gage corner, with the hardness of the gage corner being greater than that of the center of the rail head surface by a minimum of Hv 30." has been added after the term "… lower temperature zone"

XIV. Claim 1 of auxiliary request 5 differs from claim 1 of the main request in that the feature "to a cooling stop temperature of 500º to 300ºC" has been deleted and that the feature "for avoiding the formation of coarse-grained bainite structures and starting bainite transformation with fine-grained bainite structures in a lower temperature region, the accelerated cooling being performed by air, mist or an air-atomized liquid from nozzles disposed on both sides of the rail head, stopping the accelerated cooling at a cooling stop temperature of 500 to 300ºC," has been inserted between the term "at a rate of 1º to 10ºC per second" and the term ", and then heating …". Additionally, the feature "for making stable growth of the fine-grained bainitic structures" was inserted between the term "… from the interior of the rail" and the term "and then naturally cooling …" and that the identical hardness feature of auxiliary request 4 ", wherein the rail has a hardness of Hv 300 to 400 …" was also added.

XV. Claim 1 of auxiliary request 6 differs from claim 1 of auxiliary request 5 in that the upper value of the cooling stop temperature has been restricted to "450" ºC.

XVI. Claim 1 of auxiliary request 7 differs from claim 1 of the main request in that the feature "to a cooling stop temperature of 500º to 300ºC" has been deleted and that the feature "for avoiding the formation of coarse-grained bainite structures and starting bainite transformation with fine-grained bainite structures in a lower temperature region, the accelerated cooling being performed by air, mist or an air-atomized liquid from nozzles disposed on both sides of the rail head, stopping the accelerated cooling at a cooling stop temperature of 400 to 300ºC for suppressing excessive heat recuperation from the interior of the rail," has been inserted between the term "at a rate of 1º to 10ºC per second" and the term ", and then heating …". Additionally, the feature "to make stable growth of the fine-grained bainitic structures without coarsening bainitic structures" was inserted between the term "… from the interior of the rail" and the term "and then naturally cooling …" and that the identical hardness feature of auxiliary request 4 ", wherein the rail has a hardness of Hv 300 to 400 …" was also added.

XVII. Claim 1 of auxiliary request 8 differs from claim 1 of the auxiliary request 6 in that the first feature "for avoiding the formation … 450 to 300ºC" has been replaced by "the accelerated cooling being performed by air, mist or an air-atomized liquid from nozzles disposed on both sides of the rail head, stopping the accelerated cooling at a cooling stop temperature of 500 to 300ºC" while the second feature "for making stable growth of the fine-grained bainitic structures" has been replaced by "wherein fine-grained bainitic structures in the steel rails are formed both in the course of the accelerated cooling to a cooling stop temperature of 500 to 300ºC where the accelerated cooling is stopped and in the heat recuperation process following the accelerated cooling".

XVIII. Claim 1 of auxiliary request 9 differs from claim 1 of auxiliary request 8 in that the second feature "wherein fine-grained bainitic structures … heat recuperation process following the accelerated cooling" has been replaced by "wherein fine-grained bainite transformation begins in the course of accelerated cooling on the temperature range of 500 to 300ºC where the accelerated cooling is stopped and ends in the subsequent heat recuperation process, or it begins and ends in the heat recuperation process immediately after the accelerated cooling".

XIX. Claim 1 of auxiliary request 10 differs from claim 1 of auxiliary request 3 in that the feature "at which the bainitic transformation is not completed" has been deleted and in that the wording "wherein depending on the selected steel composition and accelerated cooling rate bainite transformation begins in the course of accelerated cooling on the temperature range of 500 to 300ºC where the accelerated cooling is stopped and ends in the subsequent heat recuperation process, or it begins and ends in the heat recuperation process immediately after the accelerated cooling" has been inserted after the feature "by using air, mist … of the rail head" and before "and then heating the rail head surface …".

XX. Claim 1 of auxiliary request 11 differs from claim 1 of auxiliary request 10 in that the feature "wherein depending on the selected steel composition … the accelerated cooling" has been deleted.

XXI. The appellant argued essentially as follows:

Claim 1 of the main request corresponds to claim 1 as granted with the deletion of the alternative according to feature f2). Hence the requirements of Articles 123(2) and (3) are met.

E21/E21a relates to a process and installation for the thermal treatment to provide bainitic steel rails having a high carbon content of 0.4-1.0% (see E21a, page 3, line 68), which is not very popular in the art (see E1, page 1, line 73; E5, page 775; E9, page 81, left-hand column, first paragraph; E20, page 380, Table 13.4, page 383, last paragraph). E21 represents a non-enabling disclosure and should thus be disregarded. The aim of E21a is to provide a uniform structure throughout the whole mass (see page 3, lines 75 to 80) but it does not teach how this should be achieved over the whole carbon concentration range. E21a contains only one statement concerning the cooling time and the person skilled in the art has to assume that this time applies not to the surface but to the whole rail. There is a contradiction per se between locally cooling at the surface and the cooling of the (real) whole rail which is not possible within said short time of 3 minutes according to said embodiment. Only samples having a small cross-section can be cooled in such a manner to obtain a homogenous structure but not real steel rails. E21a specifies an isothermal transformation, i.e. a transformation at constant temperature and does not mention any temperature increase of the rail heads surface. The bainitic transformation is completed in the fluidized bed wherein the rail is cooled (see page 5, lines 38 to 45 and lines 64 to 68). Moreover, when reading the disclosed steel composition of E21a in the context of the whole description it is only a preferred one (see page 3, lines 36 to 38 and lines 49 to 57 and lines 63 to 74). The optional suppression of the heat recuperation according to the patent in suit is done by selecting the cooling rate, the cooling stop temperature, and the temperature increase of the rail head surface during said heat recuperation (i.e. re-heating the surface by heat from the interior of the steel rail) must be measurable, e.g. as low as 1ºC (see table 7, example B). Furthermore, E21a being published in 1968, is not mentioned in the relevant state of the art considered in E20, which was published in 1992.

The closest prior art is represented by E1 for disclosing a process for producing bainitic steel rails (see page 1, line 68 to page 2, line 6). The problem to be solved is to provide high-strength steel rails having fine grained strong bainitic structure on the rail head and improved rolling-contact fatigue resistance (compare patent, [0016]). This problem is solved by the subject-matter of claim 1 of the main request (compare Table 1, examples A-J and comparative example L which is similar to E1). Neither D2 nor D7 inducing the claimed process, and E21 clearly teaches a different way of carrying out the bainitic transformation process which is much more complicated for obtaining fine-grained lower bainite. Furthermore, E21a refers to disadvantages and thus does not encourage the skilled person (see page 1, lines 18 to 30). The simplicity of the process of claim 1 is an indication for inventive step. Starting from E9 or E20 would make no difference. Claim 1 therefore involves an inventive step.

Auxiliary request 2 corresponds to auxiliary request III as filed with the grounds of appeal and only the alternative f2) has been deleted. The auxiliary requests 3-9 were made to take account of the comments made in the Board's communication and filed as a reaction thereto. Consequently, they were filed in time. The feature "at which bainite transformation is not completed" of auxiliary requests 2 and 3 is a consistent generalisation of the definition of auxiliary request 9.

Claim 1 of auxiliary request 10 is based on claim 1 of auxiliary request 2 and page 18, lines 18 to 24 of the application as originally filed so that the requirements of Articles 123(2) and (3) should be met and it should also be clear since the hardness feature has been deleted. To change a possibility ("may begin") into a fact ("begins") represents no violation of Article 123(2) EPC. This new auxiliary request was filed in order to deal with formal objections raised the first time during the oral proceedings.

The reason for filing a further auxiliary request at this stage of the proceedings is that claim 1 of auxiliary request 11 is a combination of claims 1 and 2 as granted which were combined with the remaining features from the description as originally filed (page 19, lines 20 to 22) to meet the requirements of Article 123(2) EPC. Furthermore, the patentee should have the opportunity to save as much as possible of his patent.

XXII. Respondent I argued essentially as follows:

The appellant makes assumptions with respect to the person skilled in the art without giving any evidence. Claim 1 does not specify that only the surface area is cooled and it is unusual to measure the surface temperature. Isothermal transformation according to E21a means that the temperature of the fluidised bed is kept constant (see page 2, lines 12 to 22; page 5, lines 16 to 19 and lines 38 to 41). E21a acknowledged that it uses a higher carbon content than the prior art (see page 3, lines 36 to 48). The heat recuperation is the result of the latent heat in the steel rail and of the exothermic transformation reaction so that any rail is heated. These heats are removed by the fluidised cooling medium of E21a. Claim 1 only defines the upper limit of a temperature increase but not the lower limit. Furthermore, according to the patent in suit said heat recuperation can be suppressed within certain limits (see patent, paragraph [0049]). The fast cooling according to E21a takes place within less than 3 minutes whereas according to the patent in suit when starting from 700ºC to 500ºC with a cooling rate of 10ºC/s it takes 20 seconds while with a cooling rate of 1ºC/s it takes 200 seconds. Hence no problem can be seen with such parameters which would disable the skilled person. The transformation reaction needs about 3-4 minutes after reaching the cooling stop temperature. Locally does not mean the surface but means that there may be some points somewhere in the rail which may have undergone improper cooling. The argument that E20 has not considered E21a is no proof that the process of E21a has not been put into practice. Thus E21a is an enabling disclosure and claim 1 of the main request lacks novelty over E21a.

E1 taken as the closest prior art by the appellant is arbitrarily chosen since the steel compositions for the steel rails according to E9 or E20 are closer to the steel composition of the patent in suit. There exists no reason for not combining E9 or E20 with E21 since after the hot rolling operation the transformation to bainitic structures has to be carried out. This, however, belongs to the common general knowledge (see E2/E7) and the person skilled in the art would apply this teaching if the transformation from austenite to lower bainite is desired. The heat recuperation occurs in any case and it cannot be inventive to carry out the transformation within the region of the (desired) lower bainite because otherwise a different structure would be obtained, e.g. if the temperature increase during the heat recuperation would be too high so that the region of e.g. pearlite could be reached. The heat recuperation must also take place according to E21 since it is a physical law. The heat recuperation according to claim 1 of the main request cannot make any difference with respect to inventive merit.

The auxiliary requests 3-9 were late filed and due to their late filing the features thereof could not be searched. The feature "at which the bainitic …" of auxiliary request 2 contravenes Article 123(2) EPC. The feature "by using air, …" of auxiliary request 3 may contravene Article 123(3) EPC. The hardness feature of auxiliary request 4 in combination with the cooling means represents a desideratum which cannot be used in a process claim since the expert does not know how to proceed to obtain such hardness values. The features "for avoiding …" and "for making stable …" of auxiliary requests 5 to 7 contravene Article 123(2) EPC. The first added feature of auxiliary request 8 contravenes Article 84 EPC while the second contravenes Article 123(2) EPC. Likewise auxiliary request 9 violates Articles 84 and 123(2) EPC.

Claim 1 of auxiliary request 10 contravenes Article 83 EPC since the skilled person would have to make too many attempts to succeed ("undue burden"). Otherwise this unclear feature "depending on …" is superfluous since it only defines what happens during said process. The second feature "by using air, …" has not been searched, is taken from the description and does not contribute to the accelerated cooling rate.

Auxiliary request 11 is filed too late and its features are arbitrarily chosen and not linked with the features of the invention as set out in the description of the contested patent. Thus it should not be admitted.

XXIII. Respondent II argued essentially as follows:

The person skilled in the art is always needed to interpret the documents. Claim 1 teaches him that the rail head is cooled but this implies to him that also the other part of the steel rail are cooled. Furthermore, he understands from E21 that the whole rail is bainitic but not that it is homogeneous in the sense alleged by the appellant (see E21, column 3, lines 35 and 36). Claim 1 only requires a certain steel composition, a certain fast cooling rate to a certain stop temperature and then it is allowed to naturally cool so that the result of heat recuperation can be obtained. E21 tells exactly the same, e.g. 400 seconds from a temperature from 800ºC to 400ºC with a cooling rate of 1ºC/s. E21 mentions an isothermal transformation (see column 7, lines 31 to 37). The patentee argued during the examination proceedings that the heat recuperation in the claimed process is an isothermal transformation (see letter dated 3 August 1998, page 2, point 2.2.1 c)). This transformation starts somewhere in the temperature region and starts in the cooler parts and then continues so that there will also be a heat recuperation according to E21 since it is implied by the accelerated cooling rate as argued by the appellant (compare grounds of appeal, page 7). Consequently, there should be an increase of the surface temperature. Therefore claim 1 of the main request lacks novelty with respect to E21.

Claim 1 was considered to be novel over E21 due to feature f1) which is not known therefrom. The other features a) to e) are known from E21. E21 does not say anything about said heat recuperation which does not add anything since it takes place after such accelerated cooling. It was, however, already known that such heat recuperation takes place (see E21a, page 1, lines 18 to 24). Furthermore, the patent in suit shows that a temperature increase of more than 150ºC never occurs (see Table 1, examples F and K). Hence feature f1) is not inventive. E21 has solved the problem with the steep temperature gradient during the accelerated cooling step which according to the Board's calculations is about 1.3ºC/s (see communication dated 19 November 2007, point 3.2). So, even if it is not mentioned the heat recuperation will take place. Measuring a temperature increase of 1ºC at 400ºC is not very accurate and within the measuring accuracy. But what is the additional effect if the temperature difference is about 1ºC only? The effect will be about the same as that of the rail at said temperature without such heat recuperation. The cooling fluid according to E21 may even be a heating medium when the latent heat and the heat of transformation of the rail have been removed by it.

The feature "at which bainitic …" of auxiliary requests 2 and 3 contravenes Article 123(2) EPC and the negative definition is also not allowable as such. Auxiliary requests 4-9 contain mostly features which were not addressed before and do not relate to the appeal arising from the decision of the Opposition Division. Thus these requests bring forward new matter which has not been discussed before and therefore should not be admitted with respect to Article 12 of the new Rules of Procedure of the Boards of Appeal.

Claim of auxiliary request 10 represents a new request which is not based on the requests dated 19 December 2007. Furthermore, the wording "begins" of claim 1 is inconsistent with the disclosed "may begin and end" so that Article 123(2) EPC is contravened. The latter wording implies that there may be a third possibility, e.g. that the transformation ends after the heat recuperation phase. For example, if the temperature difference is very small such as 1ºC then the duration of the heat recuperation would also be very short so that the transformation may not be completed or even may not have been started.

Auxiliary request 11 should not be admitted, mainly because the respondents were not in a position to prepare for such a combination of features. It is too late now for its filing.