"Ductility Test"

[BoltSlinger]

Does anyone have any information on a ductility test. All I know is they mentioned 12%x4D. It sounds like they are talking about testing the elongation, but I am not sure.


Thanks for the help!

 

[CoryPad]

Yes, it seems like that is elongation in percent when tested with a gage length equal to four times the diameter.

 

[FennLane]

I think 'ductility' testing is a relatively complex subject.

12% Elongation of a 4d gauge length is not a very impressive amount of ductility but would be useful to ensure that relatively high strength bolts were not brittle.

A gauge length of 4 x Diameter would be considered relatively short for conventional tensile tests but ASTM F606 does allow the testing of bolts using a machined test piece when either the bolt is too short for full section testing or the test machine available is to small to cause the bolt to fail. The requirement is to use a 0.250" diameter section with a 1" gauge length.

You can find some explanation here:

http://www.element.com/docs/default...06andfullsizebolts.pdf?Status=Master&sfvrsn=4

This method is a bit 'tricky' and could artificially lower the strength of the bolt being tested. I would look more at ASTM F606 for clarity.

If you are more generally interested in ductility then Bend Testing and Erichsen Cup and Bulge tests may be more appropriate and have something to offer.

 

[mrfailure]

You are usually using 4D in machined round tensile specimens, and not on as-fabricated parts.

 

[TVP]

Tubes are frequently tensile tested using a gage length requirement of 4xD.

 

[Qual7Eng]

Actually t s reduction in area\ductility casting testcoupons are tested as per astm a370.

 

[MagBen]

Higher percentage elongation does not absolutely mean better ductility, you agree?