A.≤0.25% B.≤0.15% C.0.25%—0.6% D.＞0.6%
A.mm B.in C.cm D.dm
A.表面不平，缺胶 B.光洁度差 C.欠硫 D.焦烧
A.0.1—0.9 B.0.1—2 C.0.1—5 D.0.1—15
A.IT B.HT C.BT D.QT
