Appeal 2007-2242
Application 10/352,997
Applicants argue the claims in four separate groups: (i) Claims 1, 2, 3,
and 9; (ii) Claims 4, 10, and 11; (iii) Claims 5, 7, 12, and 14; and (iv) Claims
6, 8, 13, and 15. Claims 1 and 2 are the only independent claims on appeal
and have been grouped together by Appellant. If there is no support for the
rejection against Claim 1, the broadest claim, then all other claims stand
with Claim 1. Claim 1 is transcribed below (Br. app. A):
1. A duplex stainless steel for use in urea manufacturing plants, in
mass %, consisting of C: 0.03% or less, Si: 0.5% or less, Mn: 2% or
less, P: 0.04% or less, S: 0.003% or less, Cr: 26 % or more, but less
than 28%, Ni: 7.3-10%, Mo: 0.2-1.7%, W: more than 2%, but no more
than 3%, N: more than 0.3%, but no more than 0.4%, with the balance
being Fe and impurities, in which the content of Cu as an impurity is
no more than 0.1%.
Findings of Fact Relating to Obviousness
1. According to Lee, there are (circa 1996) two general classes of
duplex stainless steel, UNS 31803, which is 21-23 w% Cr, and SAE 2507,
which is 24–26 w% Cr (both have several other required ranges of various
components). (Lee, p. 2, ll. 18–22.)
2. Lee's aim is to provide a duplex stainless steel that is superior in
hot ductility and high temperature oxidation resistance, while maintaining
the corrosion resistance and phase stability of heat-affected zones. (Lee,
p. 3, ll. 6–8.)
3. Lee, the only applied prior art, describes a duplex stainless steel
comprising in weight %: less than 0.03% of Carbon (C), less than 1.0% of
Silicon (Si), less than 2.0% of Manganese (Mn), less than 0.04% of
Phosphorus (P), less than 0.004% of Sulfur (S), less than 2.0% of Copper
(Cu), 5.0-8.0% of Nickel (Ni), 22-27 % of Chromium (Cr), 1.0-2.0% of
3
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 Next
Last modified: September 9, 2013