A.30% B.50% C.60% D.80%
A.HRB335、HRB400、HRB550 B.CRB335、CRB400、CRB540 C.HRB335.HRB400、HRB500 D.CRB335、CRB400、CRB500
A.10%~30% B.30%~50% C.50%~80% D.50%~100%