ANCHOR BRONZE

Users of machine parts know that an alloy contamination with as little as .001% of an element may be the cause of field failures. We take every precaution to ensure that our product meets all requirements of the specification you order.

 

Our quality control procedures are in accordance with MIL-I-45208A, the most stringent procedures required by the United States Department of Defense for procurement of Level I/Subsafe material. Anchor Bronze & Metals, Inc. supplies crucial materials for shipbuilding, aviation, defense, mining, oil well drilling and many other industrial applications.

 

All material is assigned heat numbers prior to being produced. All test results for each individual heat number are logged and products are marked with their corresponding heat numbers to ensure total mill traceability. A Certifications of Conformance is standard for all orders. Our metallurgical documentation department is capable of providing you with:

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• Spectrographic analysis - Chemical certification with a mercury-free statement.

• Mechanical testing - Tensile, yield, elongation, and hardness testing

• ​Die Penetrant & Ultrasonic testing

• Certifications to all applicable commercial and military specifications.

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Ultrasonic testing (UT) of bronze is a effective but challenging non-destructive method used to detect internal defects like porosity, shrinkage, and cracks. While standard for steel, bronze's large, coarse grain structure (especially in cast forms) causes significant sound attenuation and "noise," making signal interpretation difficult. ​​

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UT testing technical Challenges for Bronze:

Bronze alloys, particularly in cast form, present specific hurdles for standard ultrasonic equipment: 

• High Attenuation: The large, coarse grain structure of bronze significantly scatters and absorbs high-frequency sound waves, often resulting in high background noise and loss of the "back wall echo".

• Material Anisotropy: Variations in cooling rates during solidification can create an inconsistent internal structure that makes signal interpretation difficult.

• Surface Roughness: Rough-cast surfaces often require mechanical machining to ensure proper probe coupling and signal penetration. 

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Recommended Inspection Techniques:

To overcome these challenges, technicians typically adapt their approach based on the specific bronze component: 

• Low-Frequency Probes: Using lower frequencies (e.g., 1 MHz to 2 MHz) is often necessary to penetrate deeper into the coarse-grained material and reduce signal scattering.

• Phased Array UT (PAUT): This advanced method uses multiple elements to steer and focus beams, providing better coverage and more detailed cross-sections for complex-shaped bronze parts.

• Immersion Testing: Submerging the component in a water bath can improve signal consistency and is often used for automated scans of high-precision parts.

• Dual-Element (TR) Probes: These are frequently used for thinner sections or to detect near-surface defects where a single probe might struggle.​

 

Common Standards:

Inspection is typically governed by industry-specific codes to ensure accuracy: 

• ASTM B294: Standard for the ultrasonic inspection of wrought metals.

• ASTM E164: General practice for ultrasonic contact examination.

• Custom Standards: For cast bronze, acceptance criteria are often defined by the specific project's ASME or API requirements.