Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403


한국표면공학회지 (44권1호 21-25)

The Joining Quality of High Strength Bolt, Nut and Washer Set (A490) in the Extreme Conditions

극한 상태에서 A490 고장력 볼트 세트의 체결 품질 연구

Suk, Han-Gil;Cho, In-Seup;Hong, Hyeon-Sun;

강원대학교 재료금속공학과;KPF(주) 품질보증부;고등기술연구원 청정 재료 및 공정기술 연구팀;
Department of Materials and Metallurgical Engineering, Kangwon National University;Qualty Assurance Team, Korea Parts & Fasteners (KPF) Co., Ltd.;Clean Materials/Processing R & D Team, Institute for Advanced Engineering;

DOI : 10.5695/JKISE.2011.44.1.021


This test focuses on the correlation between the lubrication, ductility and strength through the change of nut lubricant which decides joining angle for A490 bolt sets required in the AASHTO (American Association of State Highway & Transportation Officials). Because the lubrication of high tension bolt, nut, washer sets becomes an important factor to ductility and joining load, the quality improvement is required for improving reliability and securing enough lubrication of maker and user. This study examines the quality characteristics required in the specification through tests because only this standard specifies joining quality in the extreme conditions (as much about two times of the joining angle on site as normal condition). Moreover, this study is limited to the test on joining axial force required in the AASHTO for the three nut lubrication conditions of A490 bolt set. It is concluded that the nuts should be coated or waxed enough for the improvement of the joining axial force and ductility of bolts required in the standards. It is shown that in the case of plain high tension bolt sets, a rust preventing lubricative oil shall be applied and the torque coefficient value for A490 bolt sets should be maintained below 0.175.


High tension bolt;Joining;Lubrication;AASHTO;