A.雙頭螺栓 B.單頭螺栓 C.緊定螺釘 D.自改螺釘
A.低碳鋼 B.中碳鋼 C.合金鋼 D.高碳鋼
A.抗拉強(qiáng)度400MPa,屈服點(diǎn)320MPa B.抗拉強(qiáng)度320MPa,屈服點(diǎn)400MPa C.抗拉強(qiáng)度與屈服點(diǎn)的比值為0.8 D.抗拉強(qiáng)度與屈服點(diǎn)的積為0.8