Izod and Charpy Impact Test Procedure for Accurate Material Toughness Analysis

Pacorr provides advanced testing instruments that play a crucial role in evaluating the impact resistance of materials, particularly plastics, composites, and metals. With a focus on durability and safety, Pacorr's Impact Testing Machines are designed to perform both Izod Impact Test and Charpy Impact Test, which are two of the most widely used methods to assess a material's ability to withstand sudden shocks or impacts. Understanding the procedure and differences between these two tests helps manufacturers ensure their products meet strict quality and safety standards.
In industries where materials are subjected to high mechanical stress, such as automotive, aerospace, electrical, and construction, it is critical to verify impact resistance before product deployment. The Izod and Charpy methods provide reliable data to evaluate material toughness, helping engineers select appropriate materials and optimize product design. With Pacorr’s Charpy and Izod Impact Testing Machines, companies get accurate, repeatable, and standard-compliant test results.

What Are Izod and Charpy Impact Tests?

Both Izod and Charpy tests are standardized methods of determining the impact strength or notch toughness of a material. These tests evaluate how much energy a specimen can absorb before breaking when struck by a swinging pendulum.
While both tests aim to measure the same property — resistance to sudden impact — the orientation of the specimen and point of impact differ, which leads to different test results and applications.
Pacorr’s Impact Testing Equipment offers precise control and calibrated force application, ensuring accurate performance under standardized test conditions.

Equipment Required for the Tests

To conduct reliable Charpy and Izod impact tests, you need the following tools and setup:
1.    Pacorr Impact Testing Machine (Charpy and Izod compatible)
2.    Standardized Test Specimens
3.    Notch Cutter or Milling Machine
4.    Pendulum Arm and Release Mechanism
5.    Digital Display or Energy Reading Scale
6.    Temperature Conditioning Chamber (if required)
7.    Protective Guard and Safety Features
Pacorr’s machines are equipped with high-precision pendulum impact systems, customizable notching fixtures, and durable construction for repeatable testing.

Izod Impact Test Procedure

Step 1: Specimen Preparation

•     Prepare a rectangular specimen (usually 63.5 mm x 12.7 mm x 3.2 mm for plastics).
•     Machine a notch using a notch cutter to standardized dimensions, typically 2.54 mm depth.
•     Condition the sample as per the standard (ASTM D256 or ISO 180) — typically at 23°C and 50% relative humidity.

Step 2: Machine Setup

•     Install the vertical clamp on the Pacorr machine to hold the sample.
•     Ensure the pendulum is raised and secured in its ready position.
•     Select appropriate hammer energy depending on the specimen type.

Step 3: Testing

•     Mount the specimen vertically with the notched side facing the hammer.
•     Release the pendulum using the trigger mechanism.
•     The pendulum strikes the specimen at its upper edge and fractures it.
•     Measure the energy absorbed by the specimen during the break — shown digitally on the display unit.

Step 4: Result Analysis

•     Record the absorbed energy in Joules.
•     Calculate impact strength using the energy value and specimen dimensions.
•     Repeat for multiple samples and average the values.

Charpy Impact Test Procedure  

Step 1: Specimen Preparation

•     Prepare a horizontal specimen (typically 55 mm x 10 mm x 10 mm).
•     Machine a standard V-notch or U-notch in the center of the specimen.
•     Condition as per the standard (ASTM E23, ISO 148) to ensure uniform test conditions.

Step 2: Machine Setup

•     Install the Charpy fixture with supports at both ends.
•     Set the hammer to appropriate height and energy level.
•     Align the specimen horizontally so the notch faces away from the pendulum.

Step 3: Testing

•     Position the specimen on the machine supports with the notch at the midpoint.
•     Release the pendulum to strike the unnotched side of the specimen.
•     Record the energy absorbed at fracture.

Step 4: Result Calculation

•     Use the energy value shown by the digital system.
•     Calculate impact toughness in Joules per square centimeter or per square inch.
•     Perform multiple tests to validate accuracy.

Pacorr machines are designed for ease of operation and minimal human error during the loading and testing phase.

Common Standards for Izod and Charpy Testing

Pacorr’s machines are fully compliant with globally accepted standards, ensuring reliable and legally recognized data. Key standards include:
1.    ASTM D256 – Standard test method for Izod impact resistance of plastics.
2.    ASTM E23 – Charpy impact testing for metallic materials.
3.    ISO 180 – Plastics — determination of Izod impact strength.
4.    ISO 179 – Plastics — Charpy impact testing method.
5.    ISO 148 – Metallic materials — Charpy pendulum impact test.
Pacorr ensures that each machine is compatible with these standards and includes adjustable features to accommodate different specimen sizes and test types.

Factors Influencing Test Results

The accuracy of both Charpy and Izod impact tester depends on several factors:

•     Notch Quality and Accuracy: Imperfect notches can skew results.
•     Material Homogeneity: Variations in material structure affect energy absorption.
•     Specimen Dimensions: Incorrect sizing can lead to invalid results.
•     Temperature: Brittle materials may behave differently at lower or higher temperatures.
•     Machine Calibration: Regular calibration of Pacorr’s machines ensures consistent outcomes.

Applications of Izod and Charpy Impact Testing

1.    Plastic Manufacturing: To assess toughness and select suitable polymers for load-bearing parts.
2.    Automotive Components: To evaluate material reliability in crash-prone scenarios.
3.    Aerospace Industry: For selecting high-strength composites and alloys.
4.    Construction Materials: To verify shock resistance of structural parts.
5.    Electrical Appliances: To ensure safety under impact loads during transportation or use.
Pacorr’s machines are widely used by manufacturers, quality labs, and academic institutions for material testing and research.

Benefits of Using Pacorr’s Impact Testing Machines

1.    Dual Testing Capabilities: One system to perform both Izod and Charpy tests.
2.    Digital Data Display: Accurate, real-time readings for absorbed energy.
3.    Rugged Construction: Built to handle repetitive industrial usage.
4.    Adjustable Fixtures: Easily switch between different test setups.
5.    Standard Compliance: Tested and verified against ASTM and ISO protocols.
6.    High Repeatability: Minimized operator influence for consistent results.
7.    User-Friendly Interface: Designed for both experts and lab technicians.

Best Practices for Accurate Impact Testing

•     Always calibrate equipment before testing.
•     Use standard conditioning procedures for all specimens.
•     Replace damaged or dulled pendulums and notch cutters.
•     Regularly maintain the machine to prevent operational errors.
•     Conduct multiple tests to average results and eliminate outliers.

With Pacorr’s impact testing systems, laboratories can confidently deliver precise and credible impact resistance data that influences material selection and product design.

Conclusion

Pacorr’s Charpy and Izod Impact Testing Machines provide reliable and standard-compliant solutions for evaluating the toughness and durability of materials. By following proper test procedures and standards, industries can ensure their materials meet critical performance requirements under real-world impact conditions. Whether you are testing metals, plastics, or composites, Pacorr’s solutions offer accuracy, ease of use, and long-term durability that support a robust quality assurance process.
For manufacturers looking to reduce product failure rates and improve material performance, investing in a Pacorr Impact Tester is a smart and essential choice.