Tensile or compression testing is routinely performed to directly evaluate material strength and ductility. Primarily used for tension testing, Apollo’s universal testing machine (UTM) has the ability to apply 60,000 lbf (~267,000 N) loads to evaluate cylindrical or rectangular cross section samples with a typical 0.5-inch diameter reduced section.
The data collected is the relative change in length of the sample and the applied force that are converted to the engineering stress and strain. The results of these tests provide four key pieces of information about a materials performance capabilities: its yield strength, ultimate tensile strength (UTS), percent elongation (ductility), and reduction of area (RA). A typical output of a tensile test on left.
Tensile Testing to Evaluate Metallurgical Bonding
Apollo-Clad also uses tensile testing to demonstrate the high quality, full metallurgical bonding of our coatings. Taking a coated sample through to failure, Apollo’s premium coatings will remain adhered to the surface of the sample even after the steel beneath has been torn apart.
Charpy Impact Testing
Apollo owns and operates a Charpy Impact (or Charpy V-Notch) testing machine to evaluate the impact performance of a material through the high-impact strain rate loading conditions of a Charpy test. The potential energy difference between swing height before and after impact represents the total energy absorbed by the sample to initiate and propagate the crack through the material. Internal friction and windage is compensated for according to ASTM standards. The machine can generate 300 ftlbs (407J) of force, and with a sample cooling bath, tests can be performed at temperatures down to liquid nitrogen temperatures (-196°C/321F).
Outside of the value of absorbed energy, measurements of the broken samples are used to quantify the lateral expansion of the shear lips and % shear of the fracture surface.