How does the marking and identification of GB angles differ from ASTM angles?

Marking and identification provide traceability. ASTM A6 requires that each piece (or bundle) be marked with the manufacturer's name or logo, the heat number, and the identifying ASTM standard (e.g., A36). This allows full traceability from the final product back to the molten heat of steel. GB/T 706 has less prescriptive requirements. It typically requires marking with the manufacturer's trademark, specification, and size. The heat number or batch number may not be marked on each piece but must be available on the quality certificate. This difference in traceability is important for critical applications. An ASTM-marked angle can be directly traced, while for a GB angle, one may need to rely more heavily on the bundle tags and the accompanying Mill Test Certificate to confirm the heat number and associated test results.