ASTM E8

[CCross]

ASTM E8, Standard Test Methods for Tension Testing of Metallic Materials, Paragraph 6.6.2.1, Full Cross Section, states that For material not exceeding 5mm in diameter...the cross-sectional area may be reduced to not less than 90% of the original area without changing the shape of the cross section.

I am looking for some clarification on this paragraph. Does this paragraph intended to convey that if a test specimens cross sectional area is reduced to not less than 90% of the original area, no matter what the resulting shape is, that it can be assumed that the original area has not changed; or does this mean that while reducing the cross sectional area to not less than 90% you can also not change the shaped of the specimen?

Thanks for your input!

 

[TVP]

It means the latter-- round cross-sections stay round after machining/sanding/etc. The cross-section should be measured after this procedure so that you have the correct value for calculation of strength.

 

[CCross]

So is there any standard for say run out when a circular sample is reduced in order to ensure that the round sample stayed round? I do not believe that someone with sand paper will be able to perfectly, within say .0001 or less of an inch, reduce a round sample diameter, but the ASTM does state that abrasive cloth or paper can be used so I would imagine their intent was to allow for "hand" reduction of the sample.