Nippon Steel Corporation

Nippon Steel Bolten Co., Ltd.

Hidetoshi Tamasaki

Nobuyoshi Uno

Masahiro Nagata

Kiyoshi Hatanaka

Toshio Miyagawa

Takayoshi Isa

Seiichi Kanazawa

Eijiro Kurata

A join structure comprises a box section column and spit T-section joined by a high strength bolt and a method secures a nut to an inside of the box section column. A Torque-Shear type high strength bolt is tightly tightened by a controlled tension and a joining method of a steel member uses that bolt. The join structure is comprised of a box section column, a split T-section attached to its outer surface, and a high strength bolt inserted from the outside of the split T-section and fastened with the nut. The nut is secured to the box section column by joining a sleeve secured to a washer formed integrally with the nut and a sleeve of a nut holding part from the outside of the column. The Torque-Shear type high strength bolt has a pintail for controlling the torque at its top.

High strength bolted structure and method of securing nut and torque-shear type high strength bolt and joining method using same

A prefastenable torque-shear bolt has a bolt cut with a thread adapted to engage a nut, and full-fastening and prefastening grips each having wrench-engaging surfaces. One end of the bolt continues to a first transition portion that is tapered like a truncated cone. The full-fastening grip extends from the first transition portion and a full-fastening break-off groove. One end of the full-fastening grip continues to a second transition portion tapered like a truncated cone. The prefastening grip extends from the second transition portion and a prefastening break-off groove. The effective area of the fracture surface of the prefastening break-off groove is smaller than that of the full-fastening break-off groove. A first burr that arises on the threaded portion side when the full-fastening break-off groove is formed by rolling is formed on the first transition portion, and the outside diameter of the first burr is smaller than the diameter of the thread bottom in the threaded portion. A second burr that arises on the full-fastening grip side when the prefastening break-off groove is formed by rolling is formed on the second transition portion.

Prefastenable torque-shear bolt

Growing community of inventors

Yukuhashi, Japan

Hidetoshi Tamasaki