Beware! Five ways to identify inferior steel
Release time:
2025-05-30
1. Hazards of inferior steel
Safety hazards: Insufficient strength leads to structural collapse (such as a factory accident in 2023).
Economic losses: Rework costs can reach 3 times the original cost.
2. 5 identification methods
①Appearance inspection
High-quality steel has a smooth surface without cracks or folds; inferior steel has rust spots and pitting.
②Dimension measurement
Use a vernier caliper to detect thickness deviation (GB/T 709 allows ±0.3mm).
③Spectral analysis
A portable spectrometer detects element content (such as whether C, Si, and Mn meet the standards).
④Mechanical testing
Tensile test to measure yield strength (Q235 requires ≥235MPa).
⑤Metallographic inspection
Microscope observation of grain size (GB/T 6394 requires ≥6 levels).
3. 2025 national standard update
Added "low alloy high strength steel" detection clause (GB/T 1591-2025).
Strengthen the qualification requirements for third-party testing agencies (CMA/CNAS certification is required).
Conclusion: When purchasing steel, be sure to ask for a test report and entrust a professional agency to conduct a re-inspection if necessary to avoid losing out on the big picture.
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