Reprint from Fastener World Magazine, Vol. 169

In the fastener world there is perhaps no more commonly used expression than “torque-tension”. So common is this term in fastener circles that it is thrown out in everyday conversation and accepted by all at face value. One can understand this, as finding the perfect “torque-tension” behavior is the Holy Grail of fastener engineering. Unfortunately, like many technical terms that have been elevated to everyday usage, the vast majority of those hearing it fail to understand the fundamental principles it is meant to describe. Take for example a recent blog posting I encountered. It was addressing the question of which is more important, torque or tension. Although it was a well-intentioned posting, even the most novice fastener engineer realizes that the bolted joint is wholly dependent on properly achieved tension. Like many of the technical terms that make up the modern lexicon (such as fusion, heat treating, Xeroxing, and hundreds of others), the term “torque-tension” is broadly used by purveyors and users of fasteners, but generally poorly understood. So let us investigate this topic and see if we can find some simple answers into what “torque-tension” is all about.

joint is wholly dependent on properly achieved tension. Like many of the technical terms that make up the modern lexicon (such as fusion, heat treating, Xeroxing, and hundreds of others), the term “torque-tension” is broadly used by purveyors and users of fasteners, but generally poorly understood. So let us investigate this topic and see if we can find some simple answers into what “torque-tension” is all about.