GBT 222-2006 钢的成品化学成分允许偏差 英文版
This standard prescribes permissible tolerances of chemical composition of finished unalloy steel (excluding boiling steel), low alloy steel and alloy steel products versus threshold value of melted chemical composition, as well as relevant terms and definitions.
2. Terms and Definitions
This following terms and definitions are applicable to this standard.
2.1 Heat (or cast/ladle) analysis
It refers to a procedure that taking ingot sample during molten steel casting to make test sample and then carrying out chemical analysis. The analytic result refers to average chemical composition of molten steel of the same batch.
2.2 Product analysis
Product analysis refers to take sample from processed finished steel product (including steel feed) and then to analyze its chemical composition. Product analysis is mainly used to check chemical composition, and it is also called check analysis. Due to the fact that molten steel is distributed unevenly (segregation) during crystallization, composition value of product analysis is different from composition value of heat analysis sometimes.
2.3 Permissible tolerances for product analysis
It refers to that although composition value of heat analysis is within the exceed composition threshold value specified in standards due to segregation of steel composition. A permissible value is specified for the degree exceeding the threshold value, and the permissible value is the permissible tolerance for product analysis.
3. Sampling and Sample-making Methods for Product Analysis