Metallic Foil Tension Testing
ASTM E345 covers the tension testing of metallic foil at room temperature for Type A and Type B specimens. A tensile specimen is a standardized sample cross-section. It has two shoulders and a gage (section) in between. The shoulders are large so they can be readily gripped, whereas the gauge section has a smaller cross-section so that the deformation and failure can occur in this area. Refer to the Figure to see the difference between Type A and Type B Specimens. Tension tests of these specimens provide information on the strength and ductility of materials under uniaxial tensile stresses. This information may be useful in comparing alloys, quality control, and design of different materials. As specimen thickness is reduced, alternative procedure Test Method E796 may be utilized to measure ductility.
Type A and B Specimen(s)
A: Shouldered-type sample, with reduced section (dog-bone)(will neck)
B: Rectangular Parallel sample (no reduced section)
ASTM E345 covers metallic Foil, with thickness less than 0.006 in. (0.150mm). We recommend wedge grips with serrated inserts.*
*For Foils less than .003in. (0.076mm thickness,) it may be desirable to use smooth face grips with a gripping pressure of about 100 psi (0.7 MPa) for each. 0.001 in. (0.025 mm) of specimen thickness.
Various grip types can be used for metal foil tests, but we recommend wedge grips with serrated inserts. For proper gripping it is desirable that the entire width of the serrated face of each wedge be in contact with the specimen. A buffer material such as 320-grit silicon carbide paper may be introduced and inserted between the specimen and serrated faces to minimize tearing. Any tearing at the grip face results in a failed test, the specimen must break somewhere in the middle of the gauge length (reduced neck section). Universal Grip recommends a benchtop Universal Testing Machine to perform this test. The 50kN tensile tester from Galdabini can be delivered with ASTM E345 pre-programmed in the Graphworks 6 testing software.
A proper test report would consist of alloy, temper, heat number, test specimen orientation, test specimen type, as well as methods determining yield strength, elongation, and other mechanical properties.