round versus square tensile specimen 3

[djwink]

Is it more beneficial to machine a round tensile or a square tensile in order to obtain optimum properties - specifically elongation. This would be in reference to a high strength steel application.

 

[metengr]

Have you reviewed ASTM A 370 TEST METHODS AND DEFINITIONS FOR MECHANICAL
TESTING OF STEEL PRODUCTS? If not, I would strongly suggest you do so and this will answer your question.

 

[EdStainless]

Square is not a favorable test geometry. Read A370 for guidance on test sample shapes.

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P.E. Metallurgy, Plymouth Tube

 

[mrfailure]

The advice given to look in A370 is really telling you that there is no such thing as a "square" specimen - there are rectangular geometries for flats. Assuming that is what you really meant, the type of specimen you machine will really depend on product form. Elongation will be legally obtained either way. The only difference I can see may be if had needed reduction of area - a round is easier because you only need to measure one dimension (diameter), while flats may have more inaccuracy when they neck prior to final fracture.

 

[EdStainless]

He said square, so I have to believe that is what he meant.
Flat samples are nearly 2 dimensional, and so are rounds.
A truly square sample will often give you low elongations.

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P.E. Metallurgy, Plymouth Tube