A.螺栓材質(zhì)一般比螺母選低一級(jí)B.螺栓材質(zhì)一般選和螺母一樣C.螺栓材質(zhì)一般比螺母選高一級(jí)D. 不一定
A.190.6℃ B.191.7℃ C.192.3℃ D.193.7℃
A.109~1011 B.109~1010 C.108~1011 D.108~1010