ASTM B968/B968M - Flattening of Copper and Copper-Alloy Pipe and Tube
Understanding ASTM B968/B968M: A Deep Dive into the Flattening Test for Copper and Copper-Alloy Pipe and Tube
ASTM B968/B968M is a globally recognized standard that governs the flattening test for copper and copper alloy pipe and tube of all sizes. Developed by ASTM Committee B05 on Copper and Copper Alloys, this standard provides a comprehensive methodology to evaluate the ductility and surface defect presence in both seamless and welded pipes and tubes. Here’s a complete breakdown of the standard, offering insights into its scope, apparatus, procedure, and reporting mechanisms.
Scope of the Test
The test is meticulously designed to be applicable to both inch-pound and metric systems, ensuring its universal relevance. Safety and health practices are emphasized, mandating the users to adopt suitable measures to mitigate risks associated with the execution of this standard.
Equipment
The apparatus required includes a Testing Machine, capable of exerting enough pressure to flatten the pipe or tube to the mandated degree, and a Micrometer Caliper, essential for measuring the thickness of the flattened sample.
Test Specimen Preparation
For both seamless and welded products up to 4 inches in outside diameter, the specimen is cut to allow multiple flattenings along its length. Specimens may be annealed prior to testing if they are not already in the annealed temper. For products larger than 4 inches in diameter, the tube is flattened once over a specific length, ensuring a thorough inspection of ductility and surface defects.
The Flattening Procedure
Depending on the type and size of the product, the flattening procedure varies. Each test specimen undergoes a flattening process at various places along its length, ensuring a comprehensive evaluation. The flattened areas are then rigorously inspected for surface defects. For welded products, particular attention is paid to the integrity of the weld seam.
Reporting the Findings
Reports, especially from third-party laboratories, should be comprehensive, including the date of the test, sample identification, reference to the test method, the number of replicate test pieces used, and detailed test results. The reports provide an evaluation against the set criteria, offering insights into the material’s quality and suitability for intended applications.
Precision and Bias
The test’s outcome is binary, indicating either a pass or fail relative to the presence of defects as per the criteria outlined in the procedure and product specification. It makes no statement about the precision or bias since the focus is on conformance to the established criteria.
Closing Remarks
ASTM B968/B968M is instrumental in ensuring the quality and reliability of copper and copper-alloy pipes and tubes. It underscores the importance of meticulous testing to ascertain the material’s ductility, the integrity of weld seams, and the absence of surface defects. In adhering to this standard, manufacturers and users alike can ensure the optimal performance and longevity of the material in its intended applications, guaranteeing safety and efficiency. Always consult the latest edition of the standard to stay abreast of any revisions or updates for the most accurate and current testing protocols.