T 0107/14 22-09-2015

Summary of Facts and Submissions

I. By its decision posted on 9 December 2013 the opposition division rejected the opposition against European patent No. 1835041.

II. The appellant (opponent) lodged an appeal against that decision in the prescribed form and within the prescribed time limit.

III. Oral proceedings before the Board of Appeal were held on 22 September 2015.

IV. The appellant requested that the decision under appeal be set aside and that the patent be revoked. As an auxiliary request it requested that the following questions be referred to the Enlarged Board of Appeal:

1. Is the term "consisting of" considered directly and unambiguously derivable from the solely used term "comprising", such that no new subject-matter is introduced by an amendment of the term "comprising" to the term "consisting of"?

2. If the answer to question 1 is yes, is a compound "consisting of" essential elements and optional elements considered directly and unambiguously derivable from a disclosure of a first list of the essential elements to be "comprised" and a second list of optional elements to be comprised by the compound?

V. The respondent (patent proprietor) requested that the appeal be dismissed or, in the alternative, that the patent be maintained on the basis of one of auxiliary request 1 or 2 filed with letter of 29 July 2014.

VI. The independent claims of the main request (patent as granted) read as follows:

"1. A nickel alloy wire to be used in effecting repairs to nickel based superalloy components, said nickel based alloy being formed from a material consisting of from 4.75 to 5.25 wt% chromium, from about 5.5 to 5.8 wt% aluminum, from 5.6 to 6.2 wt% tungsten, from 8.0 to 8.3 wt% tantalum, from 1.7 to 2.1 wt% molybdenum, from 9.5 to 10.5 wt% cobalt, from 2.8 to 3.2 wt% rhenium, from 0.07 to 0.30 wt% carbon, from 0.02 to 0.04 wt% boron, from 0.08 to 0.12 wt% zirconium, from 0.08 to 0.12 wt% yttrium, from 1.0 to 1.5 wt% hafnium, up to 0.12 wt% manganese, up to 0.12 wt% silicon, up to 0.015 wt% phosphorous, up to 0.015 wt% sulfur, up to 0.20 wt% iron, up to 0.10 wt% copper and the balance nickel."

"3. A method for repairing a crack in a nickel based superalloy component comprising the steps of:

providing a workpiece having a crack;

heating said workpiece to a temperature in the range of from about 1625 to 1675 degrees Fahrenheit (about 885ºC to about 913ºC) for a time in the range of from about 2.0 to 3.0 minutes; and

repairing said crack by applying a welding wire formed from a nickel based alloy having a composition consisting of 4.75 to 5.25 wt% chromium, from 5.5 to 5.8 wt% aluminum, from 5.6 to 6.2 wt% tungsten, from 8.0 to 8.3 wt% tantalum, from 1.7 to 2.1 wt% molybdenum, from 9.5 to 10.5 wt% cobalt, from 2.8 to 3.2 wt% rhenium, from 0.07 to 0.30 wt% carbon, from 0.02 to 0.04 wt% boron, from 0.08 to 0.12 wt% zirconium, from 0.08 to 0.12 wt% yttrium, from 1.0 to 1.5 wt% hafnium, up to 0.12 wt% manganese, up to 0.12 wt% silicon, up to 0.015 wt% phosphorous, up to 0.015 wt% sulfur, up to 0.20 wt% iron, up to 0.10 wt% copper and the balance nickel to said crack and maintaining said temperature until said material flows into and fills said crack."

The auxiliary requests are not relevant for this decision.

VII. The following documents played a role for the present decision:

D5: WO -A- 95/35396;

D14: P. Spiekermann "Legierungen - ein besonderes patentrechtliches Problem?" Mitteilungen der deutschen Patentanwälte (1993), pages 178-190

VIII. The arguments of the appellant can be summarised as follows:

Article 100(c) EPC

Claim 1 as originally filed was directed to a composition "comprising" a plurality of alloying elements. Therefore, it related to an open composition, as was also clear from the fact that further alloying elements were added in dependent claim 3. The use of the word "balance" in original claim 1 did not change that, because this wording merely meant that the majority of the alloy was constituted by Ni, but did not exclude further elements.

By contrast, granted claim 1 was directed to an alloy "consisting" of a plurality of alloying elements, i.e. a closed composition which did not allow the presence of further elements. A closed composition was not the same as an open one. This was also clear from the practice of the EPO, documented by D14, to object to the latter as lacking clarity.

The change from an open to a closed composition in claim 1 resulted in an addition of subject-matter which was not disclosed in the application as originally filed. In this respect reference was made also to T 725/08 and T 759/10.

Article 100(b) EPC

Reference was made to the written proceedings, where it had been argued that the weld wire of claim 1 was not suitable for repairing any Ni-based superalloy, because the boron content should be varied according to the substrate to be repaired. Therefore, the claimed invention was not sufficiently disclosed.

Inventive step

Claim 27 of D5 represented the most relevant prior art. The sole difference of claim 1 of the main request in respect of this prior art was the higher content of B. This was because in the preferred repair method of D5, which employed laser cladding, there was no need to use large quantities of B. However, the person skilled in the art knew that when the alloy of claim 27 was to be used in a repair process involving welding, the melting point of the welding wire was to be lowered, and that an increased amount of B could be used for this purpose. D5 itself described this effect of B on page 6, rendering it obvious to adopt this measure. The disadvantages mentioned on page 14 were not a hindrance in this sense, since they concerned only laser cladding. Since there was no need to modify the content of other alloying elements it was obvious to modify the alloy of claim 27 by simply increasing the B content, i.e. in the sense of claim 1. Therefore, the subject-matter of this claim did not involve an inventive step.

Request to refer questions to the Enlarged Board of Appeal

There were divergencies in the case law concerning the replacement of "comprising" with "consisting of" in the case of a composition. For instance, decisions T 0725/08 and T 0759/10 deviated from the earlier jurisprudence which allowed this amendment. Therefore, to clarify this point of law it was necessary to refer the proposed questions to the Enlarged Board of Appeal.

IX. The arguments of the respondent can be summarised as follows:

Article 100(c) EPC

It was true that claim 1 as originally filed was directed to a composition "comprising" a plurality of alloying elements. However, the claim recited also that the balance, i.e. the rest, of the composition was Ni. Therefore, claim 1 as originally filed was already directed to a closed composition. The same applied to claim 3 which, by its reference to claim 1, also incorporated the feature that the balance of the composition was Ni. Therefore, the change of wording from "comprising" to "consisting of" did not involve any change of meaning in respect of the originally filed claims. Accordingly, no subject-matter extending beyond the content of the original application had been added.

Article 100(b) EPC

Reference was made to the arguments submitted in the written proceedings, where it had been argued that the patent sufficiently described how to realise the claimed wire and use it in a method for repairing a crack.

Inventive step

Claim 27 of D5 represented the most relevant prior art. Starting from this prior art the invention provided a wire for repairing cracks by welding in materials exhibiting strength and oxidation resistance at high temperature. D5 led away from the claimed solution since it did not relate to welding and disclosed higher amounts of B as disadvantageous. Therefore, the subject-matter of claim 1 of the main request involved an inventive step.

Request to refer questions to the Enlarged Board of Appeal

There was no need to refer the questions proposed by the appellant to clarify a point of law.