Re-Use of Tensionned Bolts

goub...

I do not think that there is a single answer to this question..... in other words, sometimes yes and sometimes no.

My opinion is the following...

For bolts that have seen continuous high temperature duty (say above 750F)...NO

For some critical service bolts (where failure causes loss of life/extreme property damage).....NO

For bolts that are subject to an extreme corrosive atmosphere.......NO

For some materials, or in situations where the bolt is designed for and subject to loadings that are a high percentage of yield (say 75%)....NO

All others....YES

Again, a company guideline built around the concepts noted above would be very useful..... any such guideline would be subjective.

I do not believe the "international standards" that you mention exist....

Regards

Many thanks for your answer MJCronin

I start getting a more clear pic

Best regards

MJCronin has given almost good answer.

I have not come across any international standard for used bolts but certain equiment manufacturer do give fixed schedules for replacement of hardwares. e.g. Gas Turbine etc. In such services never take chance by using used bolts after the schedule interval.

If the bolts have been tensioned beyond the elastic range and into the plastic range, they should not be reused.

If they have previously been tensioned only within the elastic range, they should still be reusable, unless there are fatigue issues from repeated excursions even within the elastic range.

Sometimes one cannot tell; in such cases use new bolts.