Checklist: Verifying Magnesium Alloy Certification for Import

Why verify magnesium alloy imports?

Imported magnesium parts often arrive with a paper trail that is incomplete or inconsistent. A buyer in one region may receive a casting from a foundry in another, and the paperwork may not reflect the exact batch that was melted. Without verification, a part can pass a dimensional check and still fail in service because the alloy composition drifted outside the accepted limits.

Magnesium alloy is reactive. It corrodes quickly if exposed to moisture or chlorides. The alloy grade also affects machinability, surface finish, and corrosion resistance. A mislabeled alloy can cause a part to fail in plating, welding, or long-term use. Verification is not just a formality. It is a risk control.

This checklist is for buyers, engineers, and quality auditors who receive magnesium die casting parts. It groups the checks into four themes: document review, material identification, physical inspection, and chemical verification. Use it as a copyable audit tool.

Check the document chain

Start with the paperwork. A valid import verification begins with a clear chain of custody. If the documents do not match, stop. Do not proceed to physical testing.

1. Request the commercial invoice and packing list.
2. Request the material test certificate from the foundry or mill.
3. Request the heat number stamped or laser-etched on the part.
4. Compare the heat number on the part to the heat number on the certificate.
5. Check that the quantity on the invoice matches the quantity in the packing list.

Red flag: The heat number on the part is not visible. It is covered by paint, plating, or a label. A heat number that is only on the box and not on the part is a weak traceability link. If the part is plating, the heat number must be visible under the coating or recorded in the plating log.

Red flag: The certificate lists a grade name but does not show the chemical analysis. A grade name tells you what the alloy is supposed to be. It does not tell you what it actually is. You need the actual percentages of magnesium, aluminum, manganese, silicon, and iron.

Red flag: The certificate is signed by a third party who is not the foundry or the mill. If the supplier is a reseller, ask for the original mill certificate. A reseller certificate is a reissue. It is acceptable if it includes a reference to the original document, but the original data must be present.

Identify the specific magnesium alloy

Not all magnesium alloys are the same. The most common die casting grades are AZ91, AM60, and A380. Each has different properties. AZ91 is a general purpose alloy with good corrosion resistance. AM60 has better formability and strength. A380 has high fluidity and is often used for thin-walled parts.

Red flag: The specification calls for AZ91, but the certificate shows AM60. Do not accept the parts. The mechanical properties and corrosion behavior will be different. A part designed for AZ91 will not perform the same in AM60.

Red flag: The alloy grade is listed as “Magnesium Alloy” without a specific designation. This is too vague. You need the exact grade. If the buyer did not specify the grade, the supplier may have chosen a cheaper grade.

Red flag: The alloy grade is not listed in the specification, but the part is used in a critical application. If the buyer did not specify the alloy, the supplier may have chosen a cheaper grade. You must verify the alloy before accepting the part.

Check the heat number and traceability

The heat number is the link between the raw material and the finished part. It should be present on every part, or at least on a representative sample. If the heat number is missing, you cannot verify the composition.

Red flag: The heat number is stamped on the part, but the stamp is too small to read. Use a loupe or a camera to photograph the number. If it is still illegible, reject the part.

Red flag: The heat number on the part does not match the heat number on the certificate. This is a stop condition. Do not test the parts. The documents are wrong. Return the parts to the supplier.

Red flag: The heat number is on the part, but the certificate is for a different heat number. This means the part is from a different batch than the one being certified. The composition may be different. The corrosion resistance may be different.

Inspect the surface for contamination

Magnesium alloy is susceptible to corrosion. Salt contamination is a common problem. Sodium chloride, calcium chloride, or other chlorides can be on the surface of the part. They cause pitting and cracking, especially in plating applications.

Red flag: White or blue-green spots on the surface. This is a sign of corrosion or salt contamination. Do not accept the part until it is cleaned and re-inspected.

Red flag: A chalky white residue on the surface. This may be a protective coating, but it may also be a sign of corrosion. Ask the supplier to explain the coating. If it is not listed in the specification, reject the part.

Red flag: The part has a strong smell. Magnesium alloy should not have a strong smell. A chemical smell may indicate a cleaning agent or a corrosion inhibitor that was not listed in the specification.

Red flag: The part has been stored in a humid environment. Magnesium alloy absorbs moisture quickly. If the part has been stored without a desiccant or a protective coating, it may have absorbed moisture. This can cause corrosion.

Verify the chemical composition

The material test certificate should show the actual chemical analysis. Check the values against the specification. The values must be within the accepted limits. If a value is out of range, the part is not compliant.

Red flag: The iron content is high. Iron is a non-metal that can cause inclusions. High iron content reduces the strength and ductility of the alloy. It can also cause porosity.

Red flag: The manganese content is low. Manganese is a deoxidizer. It prevents the formation of inclusions. Low manganese content can cause defects in the casting.

Red flag: The aluminum content is high. Aluminum increases the strength and hardness of the alloy. But too much aluminum can make the alloy brittle. Check the specification for the accepted range.

Red flag: The certificate does not show the test method. A chemical analysis is only as good as the test method. Ask the supplier to confirm the method. If the method is not listed, the data is not reliable.

Verify the mechanical properties

The material test certificate should also show the mechanical properties. Tensile strength, yield strength, and elongation are the key properties. Check the values against the specification.

Red flag: The tensile strength is below the specification. The part may not hold up under load. Do not accept the part.

Red flag: The elongation is low. Low elongation means the alloy is brittle. It may crack under impact or vibration. Do not accept the part.

Red flag: The certificate does not show the mechanical properties. Ask the supplier to provide the data. If the data is not available, the part is not fully verified.

Check the plating and coating

If the part is plated or coated, check the coating. The coating can hide defects. It can also trap moisture or salt.

Red flag: The coating is thick and uneven. This may indicate a defect in the casting. The coating may also trap moisture. Ask the supplier to remove the coating and re-inspect.

Red flag: The coating is peeling. This is a sign of poor adhesion. The coating may have been applied to a contaminated surface. Do not accept the part.

Red flag: The coating is not listed in the specification. If the buyer did not specify the coating, the supplier may have added it. This can change the corrosion behavior. Ask the supplier to explain the coating.

Check the storage and shipping conditions

Magnesium alloy is sensitive to storage and shipping conditions. If the part has been stored in a humid environment, it may have absorbed moisture. If it has been shipped without a protective coating, it may have corroded.

Red flag: The part was shipped in a plastic bag without a desiccant. This is a bad sign. The part may have absorbed moisture. Ask the supplier to explain the packaging.

Red flag: The part was shipped in a cardboard box without a protective coating. This is a bad sign. The part may have corroded. Ask the supplier to explain the packaging.

Red flag: The part was shipped in a humid environment. This is a bad sign. The part may have absorbed moisture. Ask the supplier to explain the storage conditions.

Red flags to watch for

Red Flag	Why It Matters	Action
Heat number does not match certificate	The part may be from a different batch.	Reject the part. Return to supplier.
Chemical analysis is missing	You cannot verify the composition.	Do not accept the part. Request the data.
Surface has white or blue-green spots	Sign of corrosion or salt contamination.	Reject the part. Request a cleaning report.
Iron content is high	Reduces strength and ductility.	Reject the part. Request the data.
Coating is not in specification	Can trap moisture and change corrosion behavior.	Reject the part. Request an explanation.
Part was stored without a desiccant	May have absorbed moisture.	Reject the part. Request storage records.

How to use this checklist

Print the checklist. Use it for every shipment of imported magnesium parts. Do not skip steps. If a step fails, stop. Do not proceed to the next step. The goal is to verify that the part is what the supplier says it is. If the document chain is broken, the part is not verified.

This checklist is not a substitute for testing. It is a first line of defense. If you need more assurance, request a sample for third-party testing. A third-party lab can verify the composition and mechanical properties. But the first line of defense is the document review. If the documents are wrong, the testing will not save you.

Final notes

Imported magnesium parts are not as risky as imported steel parts. But they are more reactive. The alloy grade, the heat number, and the surface condition all matter. A part can pass a dimensional check and still fail in service. The document review is the first step. If the documents are clean, proceed to physical inspection. If the documents are not clean, reject the part.

The goal is not to be difficult. The goal is to be sure. A verified part is a part that will perform as expected. An unverified part is a risk. Use this checklist to manage that risk.