Session: CT-04-02 Assembly of Bolted Joints-2

Paper Number: 154950

154950 - Effects of Side Load on Bolt Load Efficiency With Powered Torque Tools 

Abstract: 

In industrial bolting, calibrated torque tools generate accurate torque outputs by applying a counter reaction force on a stationary point that is very often the adjacent nut. This force induces a bending moment (side load), which can adversely affect the efficiency of both the torque tool and the fasteners. Additionally, side load can also be affected by the moment caused by tool elevations typical of square drive tools. By understanding the impacts side load has on pre-load, users can adjust their bolt-up procedures to create a more accurate and uniform distribution of pre-load which is paramount in ensuring the leak-tight integrity of flange connections or other mechanical assemblies.

The primary objective of this study was to comprehensively evaluate the different pre-loads achieved with several torque tools, including battery-powered, square drive hydraulic-powered, and low clearance hydraulic models, when equipped with various reaction members: short reaction arm, long reaction arm, and ASTM F3394/F3394M washers. Through rigorous testing, the impact of these distinct tool-reaction member combinations was assessed by measuring the final pre-load imparted on the fasteners.

Testing using calibrated torque tools demonstrated a direct link between reduced side load and increased pre-load. Tools equipped with drivers for ASTM F3394/F3394M washers, which suppress side load, consistently achieved higher pre-loads across all tests. Additionally, longer reaction arms proved more effective in mitigating side load and attaining higher pre-loads compared to shorter arms. By understanding the results of this study, users will be enabled to make informed decisions regarding the selection of torque tools and reaction members that optimally suit their specific applications.

Presenting Author: Michael Dolan HYTORC

Presenting Author Biography: Michael Dolan is a bolting expert with 25 years of design and field experience. Over his career he has developed innovative fastening solutions, including contributions to nuclear reactor pressure vessel fastening systems that are used worldwide today. As Chief Engineer of Fasteners at HYTORC Corporation, Mike holds several patents for specialized products that are transforming industrial connections. He works closely with OEMs, EPCs, and asset owners to optimize high-quality, large-scale threaded connections. Mike earned his mechanical engineering degree from West Virginia University

Authors:

Emmanuel Derillac HYTORC
Michael Dolan HYTORC
Brandon Bounds Bechtel Energy Inc.
Chris P. Lilley Chevron Products Company