Summarize the representation of product brand names, generally using a combination of Chinese phonetic alphabet, chemical element symbols, and Arabic numerals. Namely:
① The chemical elements in the steel grade are represented by international chemical symbols, such as Si, Mn, Cr, etc. Mixed rare earth elements are represented by "RE" (or "Xt").
② Product names, uses, smelting and pouring methods, etc., are generally represented by abbreviated letters in Chinese pinyin The content of main chemical elements in steel (%) is expressed in Arabic numerals. When using Chinese pinyin letters to represent the product name, purpose, characteristics, and process method, the first letter is generally selected from the Chinese pinyin representing the product name. When repeating the letter selected for another product, you can use the second or third letter instead, or select the first pinyin letter from both Chinese characters at the same time. "If there are currently no available Chinese characters or pinyin, the symbols used are English letters.".