screw relaxation

[KalleH]

Does anyone have a reference for the relaxation of screw joints in micrometer as function of aspects such as surface roughness and paint type and paint thickness?

Thanks!

 

[diamondjim]

Do not use paint on interfaces.

 

[KalleH]

That is easy to say if you are not in the heavy vehicle business, where this is standard on chassis, to which brackets are bolted.

 

[Tmoose]

Someone else posted this fine link.

http://www.tech.volvo.se/standard/docs/551121.pdf

Section 5.3 discusses a factor to be applied to painted joints

 

[KalleH]

I was probably the one who posted the link to the Volvo standards. However, 5.3 is just about torque/tension relationships.

 

[CoryPad]

VDI 2230 has information regarding stress relaxation as a function of surface roughness. VDI 2230 is available from Beuth at:

http://www.beuth.de

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[diamondjim]

We have provided painted structures for
heavy equipment and used plugs to prevent
painted surfaces under the washers etc.