HB 7435-2013 A286MJ螺纹扁圆头螺栓.pdf HB 7432-2013 A286MJ螺纹十字槽平头螺栓.pdf HB 7418-2013 A286MJ螺纹短螺纹小六角头螺栓.pdf HB 7411-2013 A286MJ螺纹六角头螺栓.pdf HB 5856-2011 垫圈技术条件.pdf HB 1-218-2011 螺栓、螺钉和螺桩通用规范.pdf HB 1-217-2011 螺栓和螺钉的强度数据.pdf