1, ???? ???? ?? ?????? ????????? ??? ????? ?? ???? ?????? ?????????? ???? ????????. ????? ???? ???????? ???? ????, ???? ???? ???.

2. ?????? ????????? ?????:

???? ????? ????????? ???? ???? 5A50: 265MPa; ???? ????? ?? 3A21: <167MPa;

???? ????? ?? ????????? 2A11: 370MPa; ???? ????? ?? 2A12: 390 ~ 420MPa; ???? ????? ?? 2A13: 315 ~ 345MPa;

3. ???? ????? ?? ????????? ???? ???????: 80 ~ 100MPa;

4. ???? ???? ?????? ??? ????? ?????? ?? ??? ????? ??? ???? ??????? ????? ?????? ??? ???? ?????? ???? ????? ????.