GB/T 221-2008 in English

《GB/T 221-2008钢铁产品牌号表示方法》由TC183（全国钢标准化技术委员会）归口，TC183SC2（全国钢标准化技术委员会基础分会）执行，主管部门为中国钢铁工业协会。
本标准代替GB/T 221-2000《钢铁产品牌号表示方法》。
本标准规定了钢铁产品牌号表示方法。
本标准适用于编写生铁、碳素结构钢、低合金结构钢、优质碳素结构钢、易切削钢、合金结构钢、弹簧钢、工具钢、轴承钢、不锈钢、耐热钢、焊接用钢、冷轧电工钢、电磁纯铁、原料纯铁、高电阻电热合金及有关专用钢等产品牌号。

本标准与GB/T 221-2000标准相比，主要变化如下：
――增加热轧光圆钢筋、热轧带肋钢筋、细晶粒热轧带肋钢筋、冷轧带肋钢筋、预应力混凝土用螺纹钢筋、煤机用钢、高性能建筑结构用钢、低焊接裂纹敏感性钢、原料纯铁等产品牌号表示方法的规定；
――删除易切削非调质钢、塑料模具钢、电工用热轧硅钢、电讯用取向高磁感硅钢等产品牌号表示方法的规定；
――明确采用汉语拼音字母或英文字母表示产品名称、用途、特性和工艺方法时，通常采用大写字母；
――删除GB/T 221-2000中表2，将同类牌号表示方法的举例加以归纳，并以表格的形式统一列出；
――改变管线用钢、船用锚链钢符号表示方法；
――改变桥梁用钢符号表示方法；
――修改高碳铬不锈轴承钢和高温轴承钢牌号表示方法；
――修改不锈钢和耐热钢牌号表示方法；
――修改高电阻电热合金牌号表示方法；

1 Scope

This standard specifies notations for designations of iron and steel.
This standard is applicable to the preparation of designations for pig iron, carbon structural steels, low-alloy structure steel, quality carbon structural steel, free-cutting steel, alloy structure steel, spring steel, tool steel, bearing steel, stainless steel, heat-resisting steel, steel for welding, cold rolled electric steel, electromagnetic pure iron, pure iron for raw material, high resistance alloys for electrical heating and relevant steels for special use etc..
Notations for designations of iron and steel which are not specified in this standard shall be prepared in accordance with principles specified in this standard.
Notations for designations of powder metallurgical materials, cast iron (piece), cast steel (piece), ferroalloy, superalloys/high temperature intermetallic materials, corrosion-resisting alloy and precision alloy etc. shall respectively conform to provisions specified in the following national standards.
GB/T 4309 "Classification and Designation for Powder Metallurgy Materials"
GB/T 5612 "Code for Representing Cast Iron"
GB/T 5613 "Code for Representing Cast Steels"
GB/T 7738 "Notations for Designation of Ferroalloys"
GB/T 14992 "Classification and Designation for Superalloys and High Temperature Intermetallic Materials"
GB/T 15007 "Designations of Corrosion-resisting Alloy"
GB/T 15018 "Designation of Precision Alloys"

2 Basic Principles

2.1 The designation of any iron or steel listed into the national/professional standards shall be prepared in accordance with the notations for designations specified in this standard.
2.2 Capitalized Chinese phonetic letters, chemical element symbols and Arabic numerals are generally used to indicate the designations of iron and steel. For the convenience of international communication and trade, capitalized English letters or international practices may be adopted as well. Symbols of common chemical elements are detailed in Table 1.
2.3 If the Chinese phonetic alphabet or English letter is used to express the product name, purpose, characteristics and process method, generally the first letter of the phonetic transcription or the English word of the product is adopted. If the first letter is the same with that of another product, the second or third letter shall be adopted; or first letters of two (or more) phonetic transcriptions or English words shall be adopted at the same time.
If Chinese phonetic letters or English letters are adopted, in principle, only one letter is adopted; in general, the number of adopted letters shall not exceed 3.
2.4 The notation for each part of the product designation shall meet the corresponding provisions. Each part shall be arranged in the right sequence and the unnecessary ones may be omitted. Except for special regulations, no gap shall be reserved between letters, symbols and numerals.
2.5 The mass fraction is used to express the element content of the product designation.
Table 1

Contents
Foreword I
1 Scope
2 Basic Principles
3 Notations for Designations