ASTM B153 - Expansion (Pin Test) of Copper and Copper-Alloy Pipe and Tubing

ASTM B153 Expansion Pin Test for Copper and Copper-Alloy Pipe and Tubing: Procedure, Significance, and Use

Introduction

The expansion pin test is a critical method used to assess the capacity of copper and copper-alloy pipe and tubing for expansion and to identify surface defects. It provides valuable information for various applications, including research and development, engineering design, quality control, and acceptance or rejection in specifications. This article will detail the procedure of the expansion pin test and discuss its significance and use in the industry.

Scope

The expansion pin test is applicable to copper and copper-alloy pipe and tubing with an inside diameter of 0.125 in. (3.2 mm) and greater or an outside diameter up to and including 4 in. (102 mm). Tubes with an inside diameter less than 0.125 in. require an alternative test method to be agreed upon between the manufacturer and purchaser. Similarly, for tubes larger than 4 in. (102 mm) in outside diameter, the alternative test described in Test Method B968/B968M may be allowed.

Procedure

The expansion pin test involves subjecting the copper or copper-alloy tube to a controlled expansion process using a specially designed pin. The following steps outline the procedure for conducting the test:

1. Preparation:

   • Ensure the copper or copper-alloy tube to be tested is clean and free from any surface contaminants or debris.

   • Select a suitable expansion pin that fits snugly inside the tube without causing damage.

   • Calibrate the measuring instruments to ensure accurate readings.

2. Setup:

   • Position the copper tube in a fixed apparatus, ensuring it is stable and does not move during the test.

   • Insert the expansion pin into one end of the tube, making sure it is centered.

3. Expansion Process:

   • Gradually apply force to the expansion pin to expand the tube slowly and uniformly.

   • Continuously monitor the expansion using appropriate measuring devices.

   • Record the expansion force and corresponding expansion readings.

4. Surface Examination:

   • After completing the expansion process, thoroughly examine the outer surface of the expanded tube for any visible defects, such as cracks, splits, or other imperfections.

   • Take note of the location, size, and severity of any defects observed.

5. Data Analysis:

   • Analyze the expansion data to determine the maximum capacity of the tube for expansion.

   • Compare the expansion results with the specifications and requirements set by relevant standards.

6. Reporting:

   • Prepare a comprehensive report detailing the test procedure, equipment used, expansion results, and any surface defects identified.

   • Present the findings in a clear and organized manner for easy interpretation and reference.

Significance and Use

The expansion pin test holds significant importance in various aspects of the copper and copper-alloy tubing industry:

1. Quality Control: The test helps manufacturers ensure that their copper tubes meet the required expansion capabilities and are free from defects, thus maintaining high-quality products.

2. Research and Development: Researchers can use the test data to study the behavior of different copper alloys under expansion and improve materials for specific applications.

3. Engineering Design: The test results aid engineers in selecting appropriate copper tubing for specific projects, ensuring safety and performance.

4. Acceptance/Rejection Criteria: The expansion pin test plays a crucial role in determining whether a batch of copper tubes complies with industry standards and can be accepted or rejected accordingly.

5. Substitute Test Method: For larger tubes, the expansion pin test allows for the use of an alternative test method, making it versatile and adaptable to various tube sizes.

Conclusion

The expansion pin test is a valuable tool for assessing the expansion capacity and identifying surface defects in copper and copper-alloy pipe and tubing. By following the specified procedure, manufacturers, engineers, and researchers can ensure product quality, optimize material selection, and adhere to industry standards, thereby contributing to safer and more efficient applications in various fields.