There are many reasons why load can be lost in a gasketed joint. Maintaining the desired load can be a challenge at times for a variety of reasons. Today we’re going to cover some of these reasons.
Before we get into it, we want to make sure all of our readers are on the same page and understand what we mean by ‘losing load’. Load is the amount of force (pressure) placed on flanges by applying torque (tightening the bolts) to create the proper seal with the gasket. When you ‘lose load’, your bolts do not retain the torque values applied to them and the gasket will no longer seal properly.
Here are a couple of reasons why you could be losing load, which may help you troubleshoot any issues.
1. Material has creep/relaxation. Most compressible materials have some level of this which should be considered in the assembly.
2. Improper material selection. Materials exhibit different characteristics in assembled conditions. Be sure to understand the parameters to select the proper choice.
3. Insufficient load – bolts are not torqued sufficiently.
4. Bolt incorrect – bolts may be undersized or an improper grade for the load required.
5. Environmental exposure or thermal cycles can cause materials and hardware to lose load due to compression/recovery, creep/relaxation, bolt stretch/yield, etc.
Find Something That Works
The inability to achieve a proper seal due to loading issues can be a very frustrating issue to resolve. Using some of the information provided above can be a good starting point for you to resolve any of these issues. If troubleshooting seems to point back to a poor gasket material selection or a design flaw that cannot be fixed, talk to your trusted gasket material supplier. They should be able to offer a few suggestions on materials that may be better suited for your application.
What is the root cause of most of your loading issues?