1. How to initially determine the authenticity of cold-rolled coil material using the quality assurance certificate (material certificate)?
A: The quality assurance certificate is the first line of defense in verifying material authenticity, but it's not enough to simply check its presence; cross-verification is necessary.
First, verify that the basic information on the quality assurance certificate is complete and corresponds to the actual product: A legitimate quality assurance certificate should include the product name, brand, specifications, coil number, production date, mechanical property data, and chemical composition analysis results. Furthermore, the coil number on the quality assurance certificate must exactly match the coil number on the outer packaging label. If they don't match, it indicates a deceptive practice.
Second, utilize official online verification channels. Taking Shougang as an example, you can log in to their official platform and enter the quality assurance certificate number and anti-counterfeiting code (usually located in the lower left corner of the certificate) to check its authenticity. The QR code verification information on fake quality assurance certificates usually doesn't match the coil information. Most other steel mills also offer similar official website or WeChat account verification services.
2. How can I quickly distinguish genuine materials from counterfeit ones by their appearance and surface quality?
A: High-quality cold-rolled coils have a high surface smoothness, dimensional accuracy error ≤0.03mm, and are free from defects commonly found in hot-rolled coils, such as pitting and iron oxide scale.
3. How to identify materials on-site using simple physical tests?
A: No professional instruments are needed. Several simple methods can be used to preliminarily determine the authenticity of materials on-site:
Spark Test: Grind the material with an angle grinder and observe the resulting sparks. Low-carbon steel (such as Q235, SPCC) produces longer spark lines, more bursting sparks, and more distinct branching; medium-carbon steel or alloy steel produces different spark patterns. Using a known standard material (such as a section of low-carbon steel rebar for construction) as a reference makes it easier to distinguish differences.
Hardness Test: Use a portable Leeb hardness tester to quickly measure the material's hardness and compare it with the value stated on the quality certificate. Different grades of cold-rolled coils have clear differences in hardness; excessive deviations should raise suspicion.
Audio Test: Tap the steel and listen to the sound. High-quality steel produces a crisp sound when tapped, while cast iron and other mixed materials produce a dull sound due to better vibration damping. Although this method is crude, it is valuable for initial screening.
File test: Use a file to test the surface and judge the difference in hardness by feel. Steel with higher carbon content is more difficult to file.
4. Under what circumstances is third-party testing mandatory? What key indicators should be tested?
A: Professional testing by a CMA/CNAS accredited third-party testing organization is mandatory in the following situations to obtain legally valid evidence:
Large purchase quantities (e.g., tens of tons or more), where material discrepancies would result in significant losses.
Used in critical components (e.g., automotive structural parts, core components of home appliances).
Quality disputes with suppliers, requiring authoritative evidence to support claims.
Questionable warranty certificate verification results, or obvious defects discovered during visual inspection.
5. How to stipulate material-related clauses in the procurement contract to prevent the risk of material fraud?
A: The best way to prevent material fraud is to clearly define relevant binding clauses during the contract signing stage:
**Clearly define quality standards and acceptance methods:** The contract should clearly cite national standards (such as GB/T), industry standards, or enterprise standards agreed upon by both parties as the basis for acceptance, and specify the specific inspection methods and sampling rules. It can be stipulated that the test report issued by a third-party testing institution will be the final judgment basis.
**Agree on material certification document requirements:** Require the supplier to provide original quality assurance certificates with the goods, and indicate that they can be verified online through the steel mill's official platform. It can be stipulated that the information on the quality assurance certificate must correspond one-to-one with the information on the actual steel coil; any discrepancy will be considered a breach of contract.
**Set a quality objection period:** Clearly stipulate that within a specific number of days after delivery of the goods (such as 15 or 30 days), the buyer has the right to raise written objections to the material quality. During this period, the buyer has the right to take samples for third-party testing, and the testing costs will be borne by the responsible party.
**Set up a quality objection period:** Clearly stipulate that within a specific number of days after delivery of the goods (such as 15 or 30 days), the buyer has the right to raise written objections to the material quality. During this period, the buyer has the right to take samples and send them to a third party for testing, and the testing costs will be borne by the responsible party. The regulations clearly define the liabilities for breach of contract: they specify in detail how to handle situations where the materials are substandard, such as returns, exchanges, or price reductions, as well as compensation methods for losses such as lost work time and testing fees incurred as a result.