Appeal 2007-1803
Application 10/716,512
thereof (claim 1). The Appellants also claim a fitting member produced
from the aforementioned steel through separation by fracture splitting at low
temperatures (claim 4).
Representative claim 1 is reproduced below:
1. A microalloyed steel separable by fracture splitting at low
temperatures, which comprises from 0.15 to 0.35 wt% carbon, from 0.5 to
2.0 wt% silicon, from 0.5 to 1.5 wt% manganese, from 0.03 to 0.15 wt%
phosphorus, from 0.01 to 0.15 wt% sulfur, from 0.01 to 0.5 wt% copper,
from 0.01 to 0.5 wt% nickel, from 0.01 to 1.0 wt% chromium, from 0.001 to
0.01 wt% soluble aluminum, from 0.005 to 0.035 wt% nitrogen, from
0.0001 to 0.01 wt% calcium, and from 0.001 to 0.01 wt% oxygen, the
remainder comprising iron and inevitable impurities, and which satisfies the
following relationships 1 and 2:
Relationship 1,
0.6 ≤ Ceq ≤ 0.85,
wherein
Ceq = C+0.07xSi+0.16xMn+0.61xP+0.19xCu+0.17x Ni+0.2xCr;
Relationship 2,
0 ≤ TTr ≤ 1.5,
wherein TTr = (C+0.8xSi+5xP)-0.5x(Mn+Cr+Cu+Ni);
wherein the microalloyed steel lacks vanadium.
The following references are relied upon by the Examiner as evidence
of obviousness:
Vander Voort, "Embrittlement of Steels," ASM International, Properties and
Selection of Iron, Carpenter Technology Corp., 7 pages, (1991).
2
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Last modified: September 9, 2013