Calculation of Yield strength

[zebmahar]

Hello guys

I would like to ask that, what is the method of finding yield strength of the material tested on Universal Testing Machine (UTM). Due to some error our machine is not making the graph, so we have to do manual calculations for the yield strength.
Someone has advised us to calculate yield strength by taking 75% of the max load and divide it by specimen area, is this method correct or is there any alternate method available


Best Regards
Zebmahar

 

[monkeydog]

If you are going to certify the material, you need to re-run the test.

 

[CoryPad]

The method usually is the offset strain method.

You can read more here:

http://en.wikipedia.org/wiki/Yield_(engineering)

http://www.keytometals.com/Article107.htm

The proposed method of 75 % of max load is not accurate.

You need not re-run the test as long as you have the data.