Copper-Brazed Steel Tubing

A254/A254M-12: Standard Specification for Copper-Brazed Steel Tubing

Navigating the complexities of material selection for fluid conveyance systems is paramount for ensuring reliability and safety in critical applications. For engineers and designers working with fluid lines in demanding environments, understanding the established standards for materials like copper-brazed steel tubing is essential. ASTM's A254/A254M-12: Standard Specification for Copper-Brazed Steel Tubing provides an authoritative framework for specifying and manufacturing this vital component, ensuring consistent quality and performance across industries.

What is A254/A254M-12?

ASTM A254/A254M-12 is a comprehensive standard that outlines the requirements for double-wall, copper-brazed steel tubing. Developed by ASTM International, this specification addresses the material composition, manufacturing processes, and mechanical properties necessary for tubing used in general engineering applications. Its primary purpose is to establish a clear benchmark for manufacturers and a reliable guide for purchasers, ensuring the suitability of this tubing for fluid and gas transport in various industrial settings.

Scope & Purpose

This industry-leading standard governs the manufacture and acceptance of double-wall, copper-brazed steel tubing designed for general engineering use. It specifically covers tubing intended for applications such as fuel lines, brake lines, oil lines, and components within heating and cooling units, particularly within the automotive and refrigeration sectors. The standard details requirements for both single-strip and double-strip construction. While it defines material and mechanical properties, it does not specify design parameters for the end-use application itself.

Who Must Comply?

• • Primary audience: Materials Engineers, Quality Control Inspectors, Manufacturing Engineers, Design Engineers, and Procurement Specialists involved in specifying or sourcing fluid conveyance components.
• • Industries affected: Automotive Manufacturing, Appliance Manufacturing, Refrigeration and HVAC, General Manufacturing, and any industry utilizing hydraulic or pneumatic systems.
• • Compliance nature: Voluntary, but widely adopted and often mandated by customer specifications or internal quality management systems.
• • Enforcement: Typically enforced through contractual agreements, customer audits, and internal quality assurance processes.

Key Requirements Overview

The standard requires that the steel used for manufacturing the tubing be produced via commercially accepted steelmaking processes. Professionals must ensure that the tubing is fabricated by rolling steel strip and then copper-brazing it within a reducing atmosphere to create a 360-degree brazed seam. Key provisions include adherence to specified chemical composition limits for elements like carbon, manganese, phosphorus, and sulfur, as detailed in Table 1. Furthermore, the tubing must meet defined mechanical performance criteria, including minimum tensile strength, yield strength, and elongation, as outlined in Table 2, along with passing flattening, expansion, and pressure proof tests to ensure integrity and leak-tightness.

Related Standards & References

To ensure comprehensive system design and material characterization, A254/A254M-12 often works in conjunction with other ASTM standards. ASTM A370 provides essential test methods and definitions for the mechanical testing of steel products, which are directly referenced for tensile and other mechanical property evaluations. Additionally, ASTM A751 offers standardized practices for chemical analysis of steel products, crucial for verifying compliance with the specified chemical composition