COMPRESSION SUBPRESS  (ASTM D 695)

Model No. CU-SP  (low carbon steel)
Model No. WTF-SP  (17-4PH stainless)

 

Spherical Cap in Place

Spherical Cap Removed

ASTM Standard D 695 defines the testing of a laterally supported flat specimen configuration, the required fixture being Model CU-BO. In addition, an unsupported cylindrical specimen (round or square in cross section) can be tested in compression. In this case, a subpress is recommended, to insure that the loading is applied axially and that the loading surfaces are flat and parallel.

Model CU-SP (or Model WTF-SP) satisfies the demanding tolerance requirements of ASTM Standard D 695. It incorporates a hardened steel loading head and support anvil, and a hardened steel spherical cap engaging a hardened steel loading rod which moves in a precision linear bearing. The spherical cap insures that no loading eccentricities are induced from an improperly aligned testing machine.

The standard unit (shown) can accommodate specimens up to 1" in diameter and 3.5" long. The "preferred" ASTM Standard D 695 specimen size of 0.5" diameter (or 0.5" square) and 1" long (ultimate strength) or 2" long (modulus or offset yield stress) is thus well within this range.

Subpresses to accommodate specimens of larger sizes or special configurations can also be designed and fabricated.

Source of Additional Information:

1)  ASTM Standard D 695-02 (2002), "Compressive Properties of Rigid Plastics," American Society for Testing and Materials, West Conshohocken, Pennsylvania (first issued in 1942).