【国家标准】 优质碳素结构钢

This standard specifies the classification and designation, ordering information, dimensions, shape, mass, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of quality carbon structure steel bars.
This standard applies to hotrolled and forged quality carbon structure steel bars with nominal diameter or thickness not greater than 250 mm.Quality carbon structure steel bars (hereinafter referred to as steel bars) with nominal diameter or thickness greater than 250 mm may also be supplied upon agreement between the purchaser and the manufacturer.
The steel grades and chemical composition specified in this standard also apply to steel ingots, billets, blooms, steel products with other crosssections and their products.