Appeal No. 1998-2409
Application 08/398,259
result in a free sulfur content of less than about 1 ppm. The
examiner has merely provided speculation that optimizing
Osozawa’s sulfur content would result in the free sulfur content
recited in appellants’ claims, and such speculation is not
sufficient for establishing a prima facie case of obviousness.
See In re Warner, 379 F.2d 1011, 1017, 154 USPQ 173, 178 (CCPA
1967), cert. denied, 389 U.S. 1057 (1968); In re Sporck, 301 F.2d
686, 690, 133 USPQ 360, 364 (CCPA 1962). Accordingly, we reverse
the rejection over Osozawa in view of McGill.
Rejection over Moroishi in view of McGill
Moroishi discloses that sulfur has an adverse effect on the
oxidation of austenitic steels and that the oxidation resistance
of such steels can be remarkably improved when the sulfur content
is limited to not more than 0.003% (30 ppm) (col. 2, lines 46-
51). It is desirable, Moroishi teaches, to make the sulfur
content as low as possible, preferably less than 0.0015% (15 ppm)
(col. 6, lines 65-66). The lowest disclosed sulfur content is
0.001% (10 ppm) (figure; tables 2-7). Moroishi teaches that
“sulfur in an extremely small amount, i.e., not more than 0.003%
[30 ppm], easily and completely combines with any Ca, Mg, etc.
introduced into the steel from a refractory material of a furnace
structure or a slag during the preparation of the melt to form a
-5-5
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