Appeal No. 95-0112
Application 07/787,994
The reference relied on by the examiner is:
Giessen et al. (Giessen) 4,297,135 Oct. 27, 1981
Claims 1 through 13, 31, and 34 stand rejected under
35 U.S.C. § 103 as being unpatentable over Giessen.
We reverse.
The present invention is directed to a method of making
superplastic steel. The method comprises an initial step of2
rapidly solidifying molten steel into a powder, ribbon, foil, or
flake having an austenitic steel structure. The rapidly
solidified austenitic steel is next heated to a temperature of
300E to 600E C to produce superplastic steel which comprises a
mixture of ferrite steel and at least one metal carbide.
The examiner’s conclusion of obviousness is predicated on
the teachings of Giessen, a patent which discloses the rapid
solidification of metal alloys which are “rich in iron, nickel,
cobalt and chromium,” to form an ultrafine grain size. According
to the examiner Giessen discloses “the features of an alloy
formed by [a] rapidly solidified [sic, solidifying] process with
[a] grain size, [a] dispersed particle size, and [a] heat
2According to the appellant a “superplastic metal is a
highly deformable metal that does not experience the metal
fatigue that occurs upon the deformation of normal metals.”
Brief, p. 2, para. 2.
3
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