IMR Materials Testing Technical Blog

ASTM Tensile Testing Standards for Determining Material Properties under Load

The basic process of tensile testing relies on a material sample attached to a fixture that applies a tension load until failure. The following five methods are primarily material-specific, and the ASTM methods noted are a basic guide for selection based on material classification.

Properties measured by tensile testing methods:

  • Ultimate Tensile Strength
  • Tensile Yield and Elongation
  • Modulus of Elasticity
  • Poisson’s Ratio

Tensile Testing of Metals

ASTM E8 / E8M is one of the most common test methods for determining the tensile properties of metallic materials, with the other being ASTM A370. These tests are performed on a variety of sample types, including cast iron bars, metal wire, specialty metals, tubes, and welded samples.  These methods cover the tension testing of metallic materials in any form at room temperature, and measure yield strength, yield point elongation, tensile strength, elongation, and reduction of area.

Non-Ambient Temperature Tensile Testing

The elevated-temperature tension test provides an assessment of the ability of metals to withstand the application of applied tensile forces, replicating in-service conditions that include high heat. The ASTM E21 standard’s principal utility is to assure that the tested material characteristics compare meets specifications for extreme environments. Conversely, materials exposed to cryogenic conditions, can be tested down to -320°F. 

Bond Strength Testing

Bond Strength (or Pull-off Adhesion testing) measures the resistance of a coating to separation from a substrate when a perpendicular tensile force is applied.  Coated substrates typically include metals, plastics, concrete, wood and glass. The ASTM C633 standard can be utilized for the testing of coatings applied by thermal spray in the form of wire, rod, or powder. These applications include plasma arc, two-wire arc, and high-velocity oxygen fuel processes for spraying feedstock. 

Polymer Tensile Testing

ASTM D638 is performed by applying a tensile force to a reinforced or non-reinforced plastic sample specimen and measuring various properties of the specimen under stress. Labs that are climate controlled are preferred testing facilities so that the plastic samples characteristics aren’t subject to variations in ambient temperature or humidity.

Composite Tensile Testing

The widely-used standard for tensile testing composite materials, ASTM D3039, applies only to those composites that are comprised of a polymer matrix reinforced by high-modulus fibers. Tensile tests are also performed on resin-impregnated bundles of fibers (“tows”), through specimens cut from thick sections of laminates, and sandwich core materials.

Summary

Tensile strength is a critical property of component design, product development, and failure analysis. Data provided by the tensile test can assist in:

  • Determining batch quality
  • Measuring manufacturing consistency
  • Aiding in the design process
  • Reducing material costs
  • Ensuring compliance with industry standards

Learn More About IMR’s Tensile Testing Capabilities

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