| 摘要 |
<p>A brake disk which has proper hardness after quenching and which is excellent in temper softening resistance and toughness is proposed. In particular, brake disk is machined from a stainless steel sheet which contains, 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 and which has a composition meeting the inequalities 5Cr + 10Si + 15Mo + 30Nb - 9Ni - 5Mn - 3Cu - 225N - 270C < 45 and 0.03 ‰¤ {C + N - (13 / 92)Nb} ‰¤ 0.09. The brake disk is quenched, whereby a martensitic structure having prior-³ grains with a diameter of 8 to less than 15 µm is obtained. This provides a brake disk which has proper hardness after quenching and high temper softening resistance and which is excellent in toughness. In order to achieve increased temper softening resistance, the stainless steel sheet may further contain Nb and/or Cu in addition to the above components.</p> |
