ASTM E517 Standard Test Method for Plastic Strain Ratio (r) for Sheet Metal

Get Reliable ASTM E517 Testing for Effective Sheet Metal Quality Control

ASTM E517 testing helps manufacturers evaluate the plastic strain ratio of sheet metals and understand their resistance to thinning during plastic deformation. Reliable strain-ratio data help manufacturers assess formability, select suitable sheet metals, optimize forming operations, and improve the consistency of formed components. Manufacturers can use these results to evaluate material performance, refine sheet metal forming parameters, and strengthen quality-control processes.

The scope of ASTM E517 includes:

• Material type: Sheet metals intended for tensile testing, metal forming, and manufacturing applications.
• Purpose: Determining the plastic strain ratio (r) of sheet metals and evaluating their resistance to thinning during plastic deformation.
• Property evaluated: Plastic strain ratio, which indicates how sheet metal deforms in the width and thickness directions under tensile strain.
• Testing method: The technician prepares a sheet metal specimen and applies a controlled tensile load. The technician measures the changes in the specimen’s width and length at the specified strain level and uses these measurements to determine the plastic strain ratio.
• Result: The analyst calculates the plastic strain ratio from the measured dimensional changes. These results help characterize sheet metal formability and compare the deformation behavior of different materials.
• Test limitations: The method evaluates the plastic strain ratio under specified tensile testing conditions. Factors such as material composition, sheet thickness, specimen preparation, surface condition, rolling direction, strain level, dimensional measurement accuracy, and testing conditions can influence the results. Users should maintain consistent testing conditions when comparing different sheet metals.
• Methodology: The technician subjects the sheet metal specimen to tensile deformation and measures the dimensional changes in the required directions. The analyst then uses the measured strain values to calculate the plastic strain ratio and assess the material’s deformation behavior.
• Applications: Sheet metal characterization, formability assessment, quality control, material selection, stamping-process optimization, deep-drawing applications, material development, and comparison of sheet metal deformation behavior.

What are the Uses of ASTM E517 Testing?

ASTM E517 testing provides quantitative data for evaluating the plastic strain ratio of sheet metals during tensile deformation. The standard test method:

• Determines the plastic strain ratio (r) of sheet metals by evaluating plastic deformation in the width and thickness directions.
• Supports quality control during sheet metal production and manufacturing processes.
• Helps manufacturers compare the formability of different sheet metals and material grades.
• Provides information about a sheet metal’s resistance to thinning during plastic deformation.
• Supports the evaluation of sheet metal behavior under specified tensile strain conditions.
• Helps identify variations in plastic strain ratio caused by material composition, rolling direction, sheet thickness, or processing conditions.
• Supports research and development of sheet metals for specific forming requirements, including stamping and deep drawing.

Why is ASTM E517 Important?

ASTM E517 is a standardized method for determining the plastic strain ratio (r) of sheet metals during tensile deformation. This measurement helps analysts evaluate a sheet metal’s resistance to thinning, compare the formability of different materials, and assess deformation behavior under controlled conditions. ASTM E517 testing results therefore support quality control, sheet metal characterization, material selection, forming-process evaluation, and optimization of sheet metal forming operations to achieve consistent product dimensions and performance.

ASTM E517 Testing Process and Data Collection

A technician first prepares a sheet metal specimen and establishes the required tensile testing conditions. The technician then secures the specimen in the testing machine and applies a controlled tensile load until the specimen reaches the specified plastic strain. During testing, the technician measures the changes in the specimen’s length and width. The technician records the initial and final dimensions and uses these measurements to determine the corresponding plastic strain values. Finally, the analyst calculates the plastic strain ratio (r) and reports the results along with the relevant specimen characteristics and test conditions.

Common Challenges and Troubleshooting

Proper specimen preparation and consistent tensile testing conditions help technicians obtain reliable and reproducible ASTM E517 results. Variations in specimen dimensions, surface condition, rolling direction, or initial gauge length can affect the measured plastic strain ratio. Incorrect specimen alignment or improper gripping can introduce bending and uneven deformation, which may lead to inaccurate strain measurements. Errors in measuring the specimen’s length and width before and after tensile deformation can also affect the calculated r-value. Inconsistent tensile loading, inadequate equipment calibration, or deviations from the specified test conditions may further influence the results. Maintaining calibrated testing equipment, accurate dimensional measurements, proper specimen alignment, and consistent testing conditions helps technicians determine the plastic strain ratio accurately and obtain repeatable results.

• The analyst reports the calculated plastic strain ratio (r) to characterize the sheet metal’s deformation in the width and thickness directions during plastic stretching.
• Analysts examine the relationship between longitudinal and width strain measurements to determine the plastic strain ratio and evaluate the material’s resistance to thinning.
• Technicians record the specimen identification, dimensions, rolling direction, target strain level, tensile test conditions, and measurement details to support accurate interpretation of the results.
• Analysts use the measured dimensional changes to calculate the relevant plastic strain values and determine the plastic strain ratio under the specified testing conditions.
• Analysts compare strain-ratio values among specimens or testing directions to identify differences in deformation behavior and directional properties.
• Engineers compare results across different sheet metal grades, material batches, or processing conditions to evaluate formability and assess material consistency.
• Overall, ASTM E517 provides quantitative information about the plastic strain ratio of sheet metal during tensile deformation. Manufacturers and researchers use these results to characterize material behavior, compare sheet metal formability, evaluate resistance to thinning, support material selection, and improve quality-control practices in sheet metal forming applications.

ASTM E517

FAQs

What does ASTM E517 measure? 

ASTM E517 measures the plastic strain ratio (r) of sheet metal to evaluate its deformation behavior and resistance to thinning during plastic stretching.

Why is the plastic strain ratio important in sheet metal forming? 

The plastic strain ratio helps manufacturers assess a sheet metal’s resistance to thinning and evaluate its suitability for forming operations such as stamping and deep drawing.

What equipment does ASTM E517 require? 

The test requires a tensile testing machine, suitable specimen grips, and dimensional measurement equipment to measure specimen deformation and determine the plastic strain ratio.

How do technicians determine the plastic strain ratio? 

Technicians apply tensile deformation to a sheet metal specimen and measure changes in its length and width. Analysts use the resulting plastic strain values to calculate the plastic strain ratio.

Which factors can affect ASTM E517 test results? 

Specimen dimensions, rolling direction, specimen alignment, gripping conditions, strain measurement accuracy, and tensile testing conditions can affect the calculated plastic strain ratio.