4.1 When a superplastic material is regularly being used in industrial production, it is often convenient to use the bulge test to qualify a batch or heat lot to an acceptance criterion. Comparing these test methods with Test Method E2448, the bulge test does not require a machined coupon, it is more convenient to perform, and it most closely simulates the multiaxial stresses and strains present in forming parts. These test methods do not measure the intrinsic superplastic properties of a material. Test Method E2448 should be used in that instance.

1.1 These test methods describe procedures for determining the biaxial formability of a superplastic metallic sheet in a circular die.

1.2 The intent of these test methods are primarily to be used as tests of superplasticity as measured by the ability to form to a prescribed depth in a die cavity without rupturing. These test methods can also be used to generate material for the measurement of cavitation in the formed part. These can be used as go/no go criteria for qualification to a specification.

1.3 These test methods have been used successfully with aluminum alloys. The use of these test methods on other metals should be verified.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.