机械零件所用金属材料多种多样，为了使生产、管理方便、有序，有关标准对不同金属材料规定了它们牌号的表示方法，以示统一和便于采纳、使用。现将常用金属材料牌号表示方法向读者作一些简单介绍。
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.标准的基本概况
1. basic survey of standards
GB/T221—2000标准是参照国外钢铁产号表示方法和国内钢铁产号表示方法变化（如Q345代替16Mn）等情况修订后，于2000年4月1日发布，并于2000年11月1日开始实施。
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.主要技术内容变动情况
2. main technical content changes
（1）由于一些钢铁产号有它们专用的标准，故取消了原标准中铁合金、铸造合金、高温合金、精密合金、耐蚀合金和铸铁、铸钢、粉末材料等牌号表示方法。
(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）一些新的钢铁产品的出现，更加完善了原标准。新标准增加了脱碳低磷粒铁、含钒生铁JP2、铸造耐磨生铁、保证淬透性钢、非调质机械结构钢、塑料模具钢、取向硅钢（电讯用）等牌号表示方法。
(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）对不适应科技发展和与生产不协调的一些用钢牌号作了彻底改变或修改。如碳素结构钢A3改为Q235，低合金高强度结构钢16Mn改为Q345等。对不锈钢、耐热钢和冷轧硅钢等的牌号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）原标准中“钢铁产号表示方法举例”的，因不适用于新标准而被删除。
(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.钢铁产号表示方法的基本原则
3. basic principles of steel product brand representation
（1）凡标准和行业标准中钢铁产品的牌号均应按GB/T221-2000标准规定的牌号表示方法编写。凡不符合规定编写的钢铁产号，应在标准修订时予以更改，一些新的钢铁产品，其牌号也应按此予以编写牌号。
(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）产号的表示，一般采用汉语拼音字母，化学元素符号和阿拉伯数字相结合的方法来表示。
(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）采用汉语拼音字母表示产品名称、用途、特性和工艺方法时，一般从代表产品名称的汉语拼音中选取个字母。当和另一个产品所选用的字母重复时，可改用第二个字母或第三个字母，或同时选取两个汉字中的个拼音字母。
(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）暂时没有可采用的汉字及汉语拼音的，采用符号为英文字母。
(4) there are no Chinese characters or Pinyin used for the time being, and symbols are used in English letters.
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