Stud bolt is necessary to install with washer or not?

[millionairevn]

Hi all,

I got a trouble with this one as per titlle. So is it necessary to install washer for stud bolt or not?

Thank you.

[FATHI]

My understanding is a studbolt with its nuts is enough.
The studbolt is a acting as a spring pressing through the joined parts.
this theory is explained in for instance some german standards or in machine design textbooks.
Please note:

1/-In asme VIII div.1 , appendix 2 , for flange design ..there is no use of washers.
2/-Same in B16.5 for flanges (rating, sizes,..)
3/-You will not see washers in vessels, piping or tank flanged connections!!..do you ?

However in mechanical design you may see washer because one wants to decrease the bearing pressure and distribute the loads ( so increase the contact area and avoid damaging the flange face), or for some hardness reasons ( washer is softer than flange), or creating an additional preload ( Belleville washers ) or to to avoid galling (= sticking)..

This is my opinion..perhaps other collegues on this site have other explanations or ideas ?

regards

[FATHI]

My understanding is a studbolt with its nuts is enough.
The studbolt is a acting as a spring pressing through the joined parts.
this theory is explained in for instance some german standards or in machine design textbooks.
Please note:

1/-In asme VIII div.1 , appendix 2 , for flange design ..there is no use of washers.
2/-Same in B16.5 for flanges (rating, sizes,..)
3/-You will not see washers in vessels, piping or tank flanged connections!!..do you ?

However in mechanical design you may see washer because one wants to decrease the bearing pressure and distribute the loads ( so increase the contact area and avoid damaging the flange face), or for some hardness reasons ( washer is softer than flange), or creating an additional preload ( Belleville washers ) or to to avoid galling (= sticking)..

This is my opinion..perhaps other collegues on this site have other explanations or ideas ?

regards