機械零件所用金屬材料多種多樣，為了使生產、管理方便、有序，有關標準對不同金屬材料規定了它們牌號的表示方法，以示統一和便于采納、使用?，F將常用金屬材料牌號表示方法向讀者作一些簡單介紹。
Mechanical parts are made of a wide variety of metal materials. In order to make production and management convenient and orderly, relevant standards for different metal materials are specified in terms of their brands, so as to show unity and easy adoption and use. We will give some brief introduction to the common methods of metal materials.
1.標準的基本概況
1. basic survey of standards
GB/T221—2000標準是參照國外鋼鐵產品牌號表示方法和國內鋼鐵產品牌號表示方法變化（如Q345代替16Mn）等情況修訂后，于2000年4月1日發布，并于2000年11月1日開始實施。
GB/T221 2000 standard is in reference to foreign steel products designation and domestic steel products designation changes (such as Q345 instead of 16Mn) and the revised, released on April 1, 2000, and in November 1, 2000 began.

2.主要技術內容變動情況
2. main technical content changes
（1）由于一些鋼鐵產品牌號有它們專用的標準，故取消了原標準中鐵合金、鑄造合金、高溫合金、精密合金、耐蝕合金和鑄鐵、鑄鋼、粉末材料等牌號表示方法。
(1) because of some grades of steel products have their specific standards, it canceled the original standard iron alloy, cast alloy, high-temperature alloy, precision alloy, corrosion resistant alloy and cast iron, cast steel, powder material designation.
（2）一些新的鋼鐵產品的出現，更加完善了原標準。新標準增加了脫碳低磷粒鐵、含釩生鐵JP2、鑄造耐磨生鐵、保證淬透性鋼、非調質機械結構鋼、塑料模具鋼、取向硅鋼（電訊用）等牌號表示方法。
(2) the emergence of some new steel products has improved the original standards. The new standards include decarburization, low phosphorus iron, vanadium pig iron, JP2, cast wear-resistant pig iron, guaranteed hardenability steel, non quenched and tempered mechanical structural steel, plastic mould steel, oriented silicon steel (Telecommunications) and other brands.
（3）對不適應科技發展和與生產不協調的一些用鋼牌號作了徹底改變或修改。如碳素結構鋼A3改為Q235，低合金高強度結構鋼16Mn改為Q345等。對不銹鋼、耐熱鋼和冷軋硅鋼等的牌號表示方法也做了修改。
(3) some steel grades that have not been adapted to the development of science and technology and production have been completely changed or modified. Such as carbon structural steel, A3 to Q235, low-alloy high-strength structural steel, 16Mn to Q345 and so on. The method of indication for stainless steel, heat-resisting steel and cold rolled silicon steel has also been modified.
（4）原標準中“鋼鐵產品牌號表示方法舉例”的，因不適用于新標準而被刪除。
(4) the example of "the method of indication of grades of iron and steel products" in the original standard is deleted because it is not applicable to the new standards.
3.鋼鐵產品牌號表示方法的基本原則
3. basic principles of steel product brand representation
（1）凡國家標準和行業標準中鋼鐵產品的牌號均應按GB/T221-2000標準規定的牌號表示方法編寫。凡不符合規定編寫的鋼鐵產品牌號，應在標準修訂時予以更改，一些新的鋼鐵產品，其牌號也應按此予以編寫牌號。
(1) in every national standard and trade standard, the grades of iron and steel products shall be written in accordance with the grades indicated by the GB/T221-2000 standard. Any steel product brand that does not meet the requirements shall be changed at the time of the standard revision, and some new steel products shall be written in accordance with this brand.
（2）產品牌號的表示，一般采用漢語拼音字母，化學元素符號和阿拉伯數字相結合的方法來表示。
(2) the indication of the brand of the product is expressed by the combination of Chinese phonetic alphabet, chemical element symbol and Arabia numeral.
（3）采用漢語拼音字母表示產品名稱、用途、特性和工藝方法時，一般從代表產品名稱的漢語拼音中選取第一個字母。當和另一個產品所選用的字母重復時，可改用第二個字母或第三個字母，或同時選取兩個漢字中的第一個拼音字母。
(3) when the Chinese phonetic alphabet is used to indicate the product name, the purpose, the characteristic and the technological method, it usually selects the first letter from the Chinese phonetic alphabet which represents the product name. When repeating the letters selected from another product, you can use second letters or third letters, or select the first phonetic letters of the two characters at the same time.
（4）暫時沒有可采用的漢字及漢語拼音的，采用符號為英文字母。
(4) there are no Chinese characters or Pinyin used for the time being, and symbols are used in English letters.
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