cmb042
Geotechnical
- Apr 28, 2008
- 39
thread404-411498
Just to follow up on an old thread I posted. I determined the issue was a change of how elongation is measured. The requirement I was referencing tested using a 2in gage length. This is the standard default gage length defined by ASTM E8. This is what is generally listed for materials in the ASTM handbook Vol 1. However per ASTM E8 for finished bar, rod, or hex the full cross section of the finished material is used, with a gage length of 4 times the diameter. E8 defines gage shapes for different products. So the cert gave an elongation value that was found testing a longer gage specimen than the reference I was using. Applying the ratio of the 4D to 2in to the elongation value brought it into agreement with the general spec.
Just to follow up on an old thread I posted. I determined the issue was a change of how elongation is measured. The requirement I was referencing tested using a 2in gage length. This is the standard default gage length defined by ASTM E8. This is what is generally listed for materials in the ASTM handbook Vol 1. However per ASTM E8 for finished bar, rod, or hex the full cross section of the finished material is used, with a gage length of 4 times the diameter. E8 defines gage shapes for different products. So the cert gave an elongation value that was found testing a longer gage specimen than the reference I was using. Applying the ratio of the 4D to 2in to the elongation value brought it into agreement with the general spec.
