How to Run ASTM E8 - Equipment List & Procedure
- christopherthomasb
- 5 days ago
- 3 min read
Equipment Needed for ASTM E8 Tensile Testing
The core equipment for applying controlled tensile loads.
Load capacity: Typically ranges from 50 kN to 600 kN, depending on material strength.
Control system: Can be servo-hydraulic or electromechanical.
Crosshead speed: Must comply with ASTM E8 strain rate requirements.
Used to hold metallic specimens securely.
Provide high clamping force to prevent specimen slippage.
Adjustable jaws accommodate different specimen sizes.
Types: Wedge grips, side-action grips, or collet grips.
3. Extensometer
Measures strain (elongation) with high accuracy.
Types:
Clip-on extensometer (for small deformations).
Automatic/non-contact extensometer (for high-precision measurement).
Gauge length: Must match ASTM E8 specimen requirements.
Material: Metal alloys, steel, aluminum, titanium, etc.
Shape: Standardized as round or flat specimens.
Dimensions: Vary based on the material thickness and test method (e.g., sub-size, full-size, and sheet specimens).
5. Software & Data Acquisition System
Records force, displacement, and calculates stress-strain data.
Provides real-time graphing of test results.
Enables compliance with ASTM E8 reporting requirements.
Used for high-temperature or cryogenic testing.
Ensures materials are tested under real-world conditions.
7. Safety Equipment
Protective shields for specimen failure protection.
Emergency stop systems on the UTM.
High-pressure hydraulic safety measures.
Procedure for Running ASTM E8 Tensile Test
ASTM E8 is the standard test method for tensile testing of metallic materials. It determines mechanical properties such as yield strength, ultimate tensile strength, elongation, and reduction of area. The procedure involves preparing a specimen, setting up the testing machine, and conducting the test under controlled conditions.
Step-by-Step ASTM E8 Test Procedure
1. Specimen Preparation
Material: The specimen must be a metallic material (e.g., steel, aluminum, titanium).
Shape & Dimensions:
Flat specimens: 12.5 mm (0.5 in) wide × 50 mm (2 in) gauge length
Round specimens: Standard diameter (e.g., 12.5 mm or 0.5 in)
Sub-size specimens: Used for limited material availability
Machining: Must follow strict tolerances for surface finish and dimensional accuracy.
Gauge Length Marking: Extensometer or manual markings at the appropriate gauge length.
2. Testing Machine Setup
Equipment Required:
Universal Testing Machine (UTM) (Electromechanical or Servo-Hydraulic)
Load Cell (to measure force)
Tensile Grips (Hydraulic, Wedge, or Mechanical) (to hold specimen securely)
Software & Data Acquisition System
Calibrate the Load Cell & Extensometer according to ASTM E8 guidelines.
3. Specimen Installation
Insert the specimen in the grips, ensuring proper alignment to prevent bending stresses.
Tighten grips to avoid slippage during testing.
4. Test Execution
Apply a tensile load at a controlled strain rate.
Crosshead speed: Typically 0.015 mm/mm/min for elastic deformation and up to 0.05 mm/mm/min for plastic deformation.
Monitor force vs. displacement on the software interface.
Observe yield point (plastic deformation begins).
Continue applying load until the specimen fractures.
5. Data Collection & Analysis
Record key results:
Yield Strength (YS): The stress where plastic deformation begins.
Ultimate Tensile Strength (UTS): The maximum stress before fracture.
Elongation (%): The total strain at fracture.
Reduction of Area (%): Measures ductility.
Generate a Stress-Strain Curve from force and elongation data.
6. Post-Test Examination
Check the fracture surface for ductile or brittle failure characteristics.
Measure final gauge length for elongation calculation.
Conclusion
The ASTM E8 tensile test is a fundamental method for evaluating the mechanical properties of metals. Proper setup, specimen alignment, and controlled loading ensure accurate and repeatable results.
Would you like recommendations on grips or extensometers for ASTM E8 testing? Contact Us!
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