Why do we use impact and not tensile testing to accept toughness?

[steelsjoe]

All,

To characterize the toughness, in my company we always use charpy to get acceptance.
From the textbook in my class the toughness of the material is also indicated by the area below the load-displacement or stress-strain curve from tensile testing.
Why we do not accept the data from the tensile testing (the area below the load-displacement or stress-strain curve) in daily life?

Regards,
Steelsjoe

 

[arunmrao]

Please go back and read once again the chapter on Impact testing " Mechanical Metallurgy" by Dieter .You will find the answer.

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"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[metengr]

In addition to the above, the area under the stress strain curve provides a qualitative measure of toughness and to allow for qualitative comparisons between materials. The Charpy impact test is also a qualitative measure of material notch sensitivity and how the material responds with a notch as a function of temperature.

The only quantitative measure of material toughness is by standard test methods which determine the stress intensity factor (K) for material.

 

[EdStainless]

In addition there is the issue of strain rate. Tensile testing is nearly static while impact testing simulates shock loading.
If you take this further if you are trying to handle resisting explosions you need to test at 10,000x the strain rate of impact testing.

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