Tag Archives: testing

Proof vs. Yield Strength

What is proof strength of a bolt and how it is different from yield strength?

Proof strength, or proof load, is the full size equivalent of a yield test. Yield testing is typically only performed on machined specimens. In most fastener standards, full size testing is the preferred method, and the referee method if there is a discrepancy between the two test results. Because of the difficulty of getting reliable... Read more

Fastener Substitution Liability

What are the liability issues involved in substituting one fastener grade or configuration for another?

Have you ever had a fastener company try and talk you into substituting A193 grade B7 all thread rod for F1554 grade 55 anchor rods, claiming it’s “better?” Have you allowed them to substitute an all thread rod with a nut tack welded in lieu of a headed bolt? These are scenarios that come up... Read more

Headed Bolts vs Rod with a Nut

Can a rod with a welded nut be substituted for a bolt with a forged head?

When a rod with a nut is substituted for a bolt with a forged head, two issues come into play. In-house mechanical testing performed by Portland Bolt on headed bolts versus rods with a nut, both from the identical lots of steel, the rod with a nut developed up to 12% less strength than the... Read more

RA% = “Reduction of Area”

What is "Reduction of Area (RA%)"?

RA% is a term that stands for “reduction of area percentage.” It is an important requirement of the ASTM F1554 specification, in addition to other specifications. This value is reported as a percentage of the original test piece. When fasteners undergo mechanical testing, they are pulled to failure and the diameter of the point at which... Read more