How to Read an Aluminum Mill Test Report (MTR)
A mill test report (MTR), also called a material test report or certificate of conformance, is the primary quality document that comes with aluminum materials from a mill. It provides the chemical composition and mechanical test results for the specific batch of material you received.
1. Material Identification
The top section of the MTR identifies the material: alloy designation (e.g., 7075), temper (e.g., T6, T651), product form (tube, bar, plate, wire rod), and dimensions. Verify that these match what you ordered.
2. Heat/Lot Number
The heat number or lot number is the traceability identifier that links the material to the specific production batch. In aerospace, full traceability back to the original melt is usually required.
3. Applicable Specification
The MTR must reference the specification the material was produced and tested to — for example, AMS 2770, ASTM B210, or AMS 4167. Verify that the specification matches what was required on your purchase order.
4. Chemical Composition
This section shows the actual chemical composition of the heat, compared to the specification limits. Verify that all elements are within the specified range.
5. Mechanical Properties
This section shows the results of mechanical testing — typically tensile strength (UTS), yield strength, and elongation. These must meet the minimum values specified by the applicable standard.
6. NDT Results
For aerospace plate and critical structural products, the MTR will include the results of non-destructive testing — typically ultrasonic testing per AMS-STD-2154.
Common Issues to Watch For
- Specification mismatch: the MTR references a different specification than what was ordered
- Missing heat treatment records for heat-treated tempers
- Generic or boilerplate MTRs not specific to the actual heat/lot
Ye Fong’s MTR Practice
All aluminum materials supplied by Ye Fong come with full mill test reports covering chemical composition, mechanical properties, heat treatment records, and NDT results.
Contact us at https://www.ye-fong.com/contact if you have any further questions.
Aluminum Mill Test Report (MTR) Frequently Asked Questions
Aluminum Mill Test Report (MTR) Frequently Asked Questions
Q1: What is an Aluminum Mill Test Report (MTR) and why is it important?
A Mill Test Report (MTR) is the definitive quality assurance document issued by the manufacturer. It certifies the chemical and physical properties of a specific batch of aluminum, ensuring material traceability and compliance with industry standards.
Q2: What are the key components to check on an Aluminum MTR?
When verifying an Aluminum MTR, you must cross-reference five critical sections against your purchase order to ensure material compliance.
Check Item | Description | What to Verify |
1. Material Identification | Alloy designation, temper, product form, and dimensions. | Matches your exact order (e.g., 7075-T651 Plate). |
2. Heat / Lot Number | Unique production batch traceability identifier. | Essential for aerospace traceability back to the original melt. |
3. Applicable Specification | Industry standards the material was tested against. | Must reference correct standards like AMS 2770, ASTM B210, or AMS 4167. |
4. Chemical Composition | Actual chemical element percentages of the heat. | All elements must fall within the allowed specification limits. |