ASTM B986 - Standard Test Method for Determination of Tensile Strength by Mass Method for Stranded Conductors Intende...

B986: ASTM B986 - Standard Test Method for Determination of Tensile Strength by Mass Method for Stranded Conductors Intended for use in Electronic Applications

In the demanding world of electronic applications, the integrity and reliability of every component are paramount. For engineers and designers working with stranded conductors, ensuring the material meets stringent mechanical requirements is crucial for product longevity and performance. ASTM B986 provides an essential, industry-leading standard for accurately determining the tensile strength of these conductors using a proven mass-based methodology.

What is B986?

ASTM B986 establishes a definitive test method for quantifying the tensile strength of uninsulated stranded electrical conductors specifically designed for electronic applications. This standard, developed by ASTM International, offers a practical approach to assessing a conductor's mechanical robustness by relating its breaking load to its mass per unit length, bypassing the complexities of direct cross-sectional area measurement in stranded configurations.

Scope & Purpose

This comprehensive standard governs the procedure for the tensile strength testing of single-type stranded conductors, which may be plain, clad, or coated. It is intended for conductors where the individual wires function collectively as a single unit. The scope explicitly covers the mass method for tensile strength determination and does not extend to composite conductors or insulated conductors.

Who Must Comply?

• • Primary Audience: Materials Engineers, Quality Control Technicians, Test Engineers, Electrical Engineers, and Product Development Engineers.
• • Industries Affected: Electronics Manufacturing, Telecommunications, Aerospace, Automotive, and Industrial Automation.
• • Compliance Nature: Voluntary, but highly recommended for quality assurance and product acceptance.
• • Enforcement: Typically enforced through contractual agreements, customer specifications, and internal quality management systems.

Key Requirements Overview

Professionals utilizing ASTM B986 must adhere to several core requirements to ensure accurate and reproducible results. The standard mandates:

• • The use of tensile testing machines calibrated according to ASTM Practices E4.
• • Precise measurement of specimen mass to within 0.1% accuracy and length to within 1/32 inch (1 mm).
• • Conducting tensile tests at a controlled loading rate, not exceeding 10 inches per minute (250 mm/min).
• • Accurate calculation of tensile strength using a formula that incorporates breaking load, mass per unit length, and a material-specific factor derived from density.
• • Consideration of any specified mass and electrical resistance increments (k-factor) from product specifications during calculations.

Related Standards & References

ASTM B986 works in conjunction with other authoritative standards to provide a complete framework for conductor testing. Key complementary standards include:

• • ASTM B354: Terminology Relating to Uninsulated Metallic Electrical Conductors, providing essential definitions for terms used in B986.
• • ASTM E4: Practices for Force Verification of Testing Machines, ensuring the accuracy and reliability of the testing equipment.
• • ASTM E8/E8M: Test Methods for Tension Testing of Metallic Materials, which provides foundational principles for conducting tensile tests, adapted here for stranded conductors by the mass method.

By adhering to ASTM B986, engineers can confidently verify the tensile strength of stranded conductors, contributing to the development and manufacturing of robust and reliable electronic products.