| 摘要 |
A brake disk excellent in temper softening resistance and toughness comprising, by mass, 0.1% or less of C, 1.0% or less of Si, 2.0% or less of Mn, 10.5% to 15.0% of Cr, and 0.1% or less of N, the remainder being Fe and unavoidable impurities, such that the following inequalities are satisfied: 5Cr+10Si+15Mo+30Nb-9Ni-5Mn-3Cu-225N-270C<45 (1) and 0.03@{C+N-(13/92)Nb}@0.09 (2) wherein Cr, Si, Mo, Nb, Ni, Mn, Cu, N, and C each represent the content of the corresponding elements on a mass percent basis, and having a martensitic structure having prior-austenite grains with an average diameter of 8 to less than 15 mum. |
