Why We Don't Provide Torque Values for Metal Seals
A commonly asked question we receive is, “Why don’t you provide torque values?”
We are providing one part of a sealing system, and there are three components — bolting, flange/groove, and our seal — that work together to create a joint, or the sealing system. A few other factors to take into account are torque friction relaxation, gasket creep, stress relaxation, flange rotation, axial movement, temperature, and hydrostatic end force.
A reality of our world is that friction will always exist and introduces an opportunity for error of +/- 30%. Thus, we provide load values, but not torque values, because you’re trying to reach a certain amount of compression in the seal (load), not torque (stress). This is why we use metal-to-metal sealing, which provides seal protection, increases bolt preload, and minimizes creep.
Run time: 2:35min
Why We Don't Provide Torque Values for Metal Seals
Video Credit: Technetics Group