A.f比v B.v比f C.ap比V D.f比ap
A.0.25%~0.8% B.0.002%~0.04% C.0.25%~0.6% D.0.04%~0.5%
A.碳素鋼 B.合金鋼 C.高合金鋼 D.不銹鋼