Thermal Mismatch and Preloads in Bolted Joints
In cryogenic bolted joints, differential contraction from mismatched Coefficients of Thermal Expansion (CTE) can cause significant preload variation. Standard torque-preloaded fasteners (e.g., 304 SS bolts clamping Aluminum 6061) lose substantial preload upon cooling — often exceeding safety margins — risking fatigue, loosening, joint separation, or overload during thermal cycling.
Calculate Preload Loss with ALLVAR Alloy 30 Constant Preload Washers and Spacers
An aluminum 60161 flange is shown bolted with 403 stainless steel bolts. Without any type of thermal mismatch compensation, the bolted joint will undergo significant preload loss, particularly when cooling down to cryogenic temperatures.
The calculator below allows you to adjust the flange length, preload, bolt size, and most importantly, ALLVAR Alloy 30 washer or spacer thickness to see the calculated effects of the preload change.
Bolt Preload Loss Calculator
Coming soon! Check back soon to see how ALLVAR Alloy 30 washers and spacers can greatly improve preload loss.
Order Constant preload Washers
Ready to significantly improve the preload of your bolted joint design? Order ALLVAR Alloy 30 washers or spacers today.
Disclaimer - Marketing Tool Only
This thermal preload calculator is provided as a marketing and educational resource only. It is not intended, and should not be used, as a substitute for professional engineering analysis, detailed finite element modeling, or validated design calculations performed by a qualified engineer.
The results generated by this tool are approximations based on simplified assumptions and generalized formulas. They may not account for all real-world variables, material variations, tolerances, environmental conditions, joint geometry, or specific application requirements.
ALLVAR makes no representations or warranties, express or implied, regarding the accuracy, completeness, reliability, or suitability of this calculator or its results for any particular purpose. Use of this tool is at your own risk.
We expressly disclaim all liability for any damages, losses, injuries, design failures, product failures, property damage, personal injury, economic loss, or any other consequences (whether direct, indirect, incidental, consequential, special, or punitive) arising from or related to the use of, reliance on, or inability to use this calculator, even if we have been advised of the possibility of such damages.
Always verify critical calculations through independent engineering analysis and testing before relying on them for design, manufacturing, or safety-related decisions.