US 2011/0030851 A1Published application

Low-carbon martensitic chromium-containing steel

AssigneeJfe Steel Corporation

InventorsKatsuhisa Yamauchi, Yasushi Kato, Takumi Ujiro, Takako Yamashita

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Abstract

A material for brake discs has temper softening resistance sufficient to maintain a hardness of HRC 31 or more after tempering at 700° C. for one hour. The low-carbon martensitic chromium-containing steel contains 0.02% to 0.10% of carbon and 0.02% to 0.10% of nitrogen, the total content of carbon and nitrogen being 0.08% to 0.16%; 0.5% or less of silicon; 0.1% or less of aluminum; 0.3% to 3.0% of manganese; 10.5% to 13.5% of chromium; 0.05% to 0.60% of niobium and 0.15% to 0.80% of vanadium, the total content of niobium and vanadium being 0.25% to 0.95%; 0.02% to 2.0% of nickel; and 1.5% or less of copper, and has an Fp value (=−230C+5Si−5Mn−6Cu+10Cr−12Ni+32Nb+22V+12Mo+8W+10Ta+40Al−220N) of 80.0 to 96.0, a hardness after quenching of HRC 31 to 40, and a hardness after tempering at 700° C. for one hour of HRC 31 or more.

Claims10

Dependent claims

A low-carbon martensitic chromium-containing steel comprising:

02% to 0.10% by mass of carbon and 0.02% to 0.10% by mass of nitrogen, the total content of carbon and nitrogen being 0.08% to 0.16% by mass;
5% by mass or less of silicon;
1% by mass or less of aluminum;
3% to 3.0% by mass of manganese;
5% to 13.5% by mass of chromium;
05% to 0.60% by mass of niobium and 0.15% to 0.80% by mass of vanadium, the total content of niobium and vanadium being 0.25% to 0.95% by mass;
02% to 2.0% by mass of nickel;
and
1.5% by mass or less of copper;
the balance comprising iron and incidental impurities, the steel having an Fp value of 80.0 to 96.0, a hardness after quenching of HRC 31 to 40, and a hardness after tempering at 700° C. for one hour of HRC 31 or more, the Fp value represented by equation (1):
Fp value=−230C+5Si−5Mn−6Cu+10Cr−12Ni+32Nb+22V+12Mo+8W+10Ta+40Al−220N (1)
wherein the element symbols denote the contents of the respective elements (% by mass).

9 more elements

Dependencies are inferred from the claim text.