What are the key differences in testing and certification between GB and ASTM angles?

Testing and certification differences are significant in GB and ASTM angle procurement. ASTM standards, such as A6, mandate a detailed Mill Test Certificate (MTC) that includes the heat number, chemical analysis from the heat, and results of mechanical tests (tensile and, if specified, impact) for each heat and lot. This provides full traceability. GB/T 706, referencing standards like GB/T 700 or GB/T 1591, also requires certification but the system can be more flexible. It often involves "third-party" inspection or factory certification. The frequency of testing can differ; ASTM often specifies a test per 50 tons from the same heat, while GB standards might specify batch testing based on tonnage or heat. Furthermore, the specific test methods differ: ASTM uses ASTM A370 for mechanical testing, while GB uses its own methods like GB/T 228.1 for tensile tests. While the results are generally comparable, strict project specifications may require testing to be performed and reported per one specific standard system.