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1 ICS H 40 GB NATIONAL STANDARD OF THE PEOPLE'S REPUBLIC OF CHINA GB/T Replacing GB/T Notations for Designations of Iron and Steel GB/T How to BUY & immediately GET a full-copy of this standard? Search --> Add to Cart --> Checkout (3-steps); 3. No action is required - Full-copy of this standard will be automatically & immediately delivered to your address in 0~60 minutes. 4. Support: Sales@ChineseStandard.net. Wayne, Sales manager Issued on: August 5, 2008 Implemented on: April 1, 2009 Jointly issued by: General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ); Standardization Administration (SAC) of the People's Republic of China.

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

3 Foreword This standard replaces GB/T "Notations for Designations of Iron and Steel". Compared with GB/T , this standard has the main change as follows: The requirements for notations for designation of products such as hot rolled plain bars, hot rolled ribbed bars, fine grain hot rolled ribbed bars, cold rolled ribbed bars, screw-thread bars for the prestressing of concrete, for coal machine, high-performance for building structure, low welding crack susceptibility and pure iron for raw material etc. (Table 3, Table 4 and 3.15 of this edition); The requirements for notations for designations of free-cutting non-quenched and tempered, plastic dies, hot rolled silicon for electrician and high-magnetic-induction silicon for telecommunication are deleted (3.6, 3.7.3, and of 2000 edition); Specifies that the capital letters shall be generally adopted while using Chinese phonetic alphabet or English letter to indicate the name, purpose, characteristic and process method of the product (2.2 of 2000 edition, 2.2 of this edition); The arrangement principles of each designation part are specified in "Basic Principles" (2.4 of this edition); Table 2 in GB/T is deleted, and examples of notations for designations in the same kind are summed up and uniformly listed in form of table (Table 2, Tables 5~8 of this edition) Notations for designations of for pipeline and marine anchor chain are changed (Table 2 of 2000 edition, Table 3 of this edition); The notation for designation of for bridge is changed (Table 2 of 2000 edition, Table 4 of this edition); Notations for designations of high-carbon chromium stainless bearing and high-temperature bearing are modified (3.8.3 of 2000 edition, of this edition); Notations for designations of stainless and heat-resisting are modified (3.9 of 2000 edition and 3.12 of this edition); The notation for designation of high resistance alloys for electrical heating is modified (3.13 of 2000 edition and 3.16 of this edition). This standard is proposed by China Iron and Steel Association. This standard is under the jurisdiction of the National Technical Committee on Iron and Steel of Standardization Administration of China. Drafting organization of this standard: China Metallurgical Information and Standardization Institute. Chief drafting staff of this standard: Dai Qiang, Ruan Yan, Liu Baoshi. The previous editions of the standard replaced by this standard are as follows: GB/T , GB/T , GB/T I

4 GB/T Notations for Designations of Iron and Steel 1 Scope This standard specifies notations for designations of iron and. This standard is applicable to the preparation of designations for pig iron, carbon structural s, low-alloy structure, quality carbon structural, free-cutting, alloy structure, spring, tool, bearing, stainless, heat-resisting, for welding, cold rolled electric, electromagnetic pure iron, pure iron for raw material, high resistance alloys for electrical heating and relevant s for special use etc.. Notations for designations of iron and 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 (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 "Classification and Designation for Superalloys and High Temperature Intermetallic Materials" GB/T "Designations of Corrosion-resisting Alloy" GB/T "Designation of Precision Alloys" 2 Basic Principles 2.1 The designation of any iron or 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. For the convenience of 1

5 international communication and trade, capitalized English letters or international practices may be adopted as well. Symbols of common chemical elements are detailed in Table 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 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 Element Symbols of chemical elements Element Symbols of chemical elements Element Symbols of chemical elements Element Symbols of chemical elements Iron Fe Lithium Li Samarium Sm Aluminum Al Manganese Mn Beryllium Be Actinium Ac Niobium Nb Chromium Cr Magnesium Mg Boron B Tantalum Ta Nickel Ni Calcium Ca Carbon C Lanthanum La Cobalt Co Zirconium Zr Silicon Si Cerium Ce Cuprum Cu Stannum Sn Selenium Se Neodymium Nd Wolfram W Plumbum Pb Tellurium Te Nitrogen N Molybdenum Mo Bismuth Bi Arsenic As Oxygen O Vanadium V Caesium Cs Sulfur S Hydrogen H Titanium Ti Barium Ba Phosphorus P Note: The "RE" is used as the element symbol of the misch metal. 3 Notations for Designations 3.1 Pig iron The pig iron's designation is generally composed of two parts. Part 1: The capitalized Chinese phonetic letter to express the product purpose, characteristic and process method; Part 2: The Arabic numerals to express the average content (in parts per thousand) of major elements, which is the average content of silicon when it comes to pig iron for making, foundry iron, pig iron for spheroidal graphite cast iron and wear-resistant pig iron, the average content of carbon when it comes to for decarbonized low-phosphorous iron, and the average content of vanadium when it comes to vanadium pig iron. Example: See Table 2. 2

6 Part 4 (if necessary): The deoxidation mode to express the symbol, namely, the rimmed, semi-killed and killed are respectively expressed as the "F" "b" "Z", but the symbol of the killed may be generally omitted; Part 5 (if necessary): The symbols of the product purpose, characteristic or process method, which are detailed in Table 4. Example: See Table Notations for designations of quality carbon spring and quality carbon structural are the same. Examples are given in Table 6. Table 6 Serial No. Product Part 1 Part 2 Part 3 Part 4 Part 5 Designation example Quality 1 carbon structural 0.05%~0.11% 0.25%~0.50% Quality Rimmed 08F Quality 2 carbon structural 0.47%~0.55% 0.50%~0.80% High-grade quality Killed 50A Quality 3 carbon structural 0.48%~0.56% 0.70%~1.00% Special-grade quality Killed 50MnE 4 Steel subject to end-quench hardenability requirements 0.42%~0.50% 0.50%~0.85% High-grade quality Killed "H", the symbol of subject to end-quench hardenability requirements 45AH 5 Quality carbon spring 0.62%~0.70% 0.90%~1.20% Quality Killed 65Mn 3.4 Free-cutting The designation of the free-cutting is generally composed of three parts: Part 1: "Y", the symbol of the free-cutting ; Part 2: The two Arabic numerals expressing the average carbon content (calculating by parts per ten thousands); Part 3: The free-cutting element symbols, for example, as for the free-cutting with free-cutting elements such as calcium, plumbum and stannum etc., they are respectively expressed by Ca, Pb and Sn. As for the free-cutting with sulpur and sulpur/phosphorus, the free-cutting element symbols such as S and P are generally not added. As for the free-cutting with higher manganese content and added with sulpur or sulpur/phosphorous, it is expressed by the manganese element symbol Mn in this part. In order to distinguish designations, the sulpur element symbol S is added at the end of the designation of the free-cutting with higher sulfur content. 7

7 For example: As for the free-cutting with the carbon content of 0.42%~0.50% and calcium content of %~0.006 %, its designation is expressed as Y45Ca; As for the free-cutting with the carbon content of 0.40%~0.48% and manganese content of 1.35%~1.65%, its designation is expressed as Y45Mn; As for the free-cutting with the carbon content of 0.40%~0.48%, manganese content of 1.35%~1.65% and sulfur content of 0.24%~0.32%, its designation is expressed as Y45MnS. 3.5 Steel for vehicle axle and rolling stock Designations of the vehicle axle and rolling stock are generally composed of two parts: Part 1: The symbol of for vehicle axle, "LZ" or the symbol of for rolling stock, "JZ"; Part 2: The two Arabic numerals to express the average carbon content (calculating by parts per ten thousands); 3.6 Alloy structure and alloy spring The designation of the alloy structure is generally composed of four parts: Part 1: The two Arabic numerals expressing the average carbon content (calculating by parts per ten thousands); Part 2: The alloy element content, which is expressed by chemical element symbols and Arabic numerals. The specific notation is: if the average content is less than 1.50%, elements are only indicated in the designation and generally, the content is not indicated; if the average content is respectively 1.50%~2.49%, 2.50%~3.49%, 3.50%~4.49%, 4.50 %~5.49%......, 2, 3, 4, 5 are correspondingly written after the alloy elements; Note: The chemical elements symbols are recommended to be arranged in descending order and according to the content. If contents of two or more elements are identical, the corresponding symbols positions are arranged according to English letters. Part 3: The metallurgy quality, namely, A and E are respectively used for the high-grade quality and special-grade quality ; as for the high quality, no letter is used; Part 4 (if necessary): The symbols of the product purpose, characteristic or process method, which are detailed in Table 4. Example: See Table The designations of the alloy spring and alloy structure are identical, see examples in Table 7. 8

8 The designation of the alloy tool is generally composed of two parts: Part 1: If the average carbon content is less than 1.00%, the single digit is used to express the carbon content (in parts per thousand). If not, the carbon content numeral is not indicated; Part 2: The alloy element content, which is expressed by chemical element symbols and Arabic numerals, and whose notation is the same as Part 2 of alloy structure. As for the alloy tool with low chromium (average chromium content is less than 1%), "0" is added prior to the chromium content (in parts per thousand) High-speed tool Notations for designations of high-speed tool and alloy structure are identical, but Arabic numerals of carbon content are generally not indicated at the head of the designation. In order to distinguish them, "C" is added at the head of the designation to for the high-carbon high-speed tool. 3.9 Bearing The bearing is divided into four kinds, namely, high-carbon chromium bearing, carburizing bearing, high-carbon chromium stainless bearing and high-temperature bearing High-carbon chromium bearing The designation of high-carbon chromium bearing is composed of two parts: Part 1: The symbol of the (ball) bearing, "G", whose carbon content is not indicated. Part 2: The alloy element symbol "Cr" and its content (in parts per thousand). As for other alloy contents, the chemical element symbol and Arabic numerals are used, whose notations are the same as Part 2 of alloy structure Carburizing bearing "G" is added at the head of the designation, and notations for designations of alloy structure are adopted. As for the high-grade quality carburizing bearing, A" is added at the end of the designation. For example: As for high-grade quality carburizing bearing with the carbon content of 0.17%~0.23%, chromium content of 0.35%~0.65%, nickel content of 0.40%~0.70%, molybdenum content of 0.15 %~0.30 %, its designation is expressed as "G20CrNiMoA" High-carbon chromium stainless bearing and high temperature bearing "G" is added at the head of the designation, and notations for designations of stainless and heat-resisting are adopted. For example: For the high-carbon chromium stainless bearing with the carbon content of 0.90%~1.00% and chromium content of 17.0%~19.0%, it designation is expressed as G95Cr18; for high temperature bearing with the carbon content of 0.75%~0.85%, chromium content of 3.75%~4.25% and molybdenum content of 4.00%~4.50%, its designation is expressed as G80Cr4Mo4V Rail and cold heading Designations of rail and cold heading are composed of three parts: 10

9 welding etc.. The designation of the for welding is generally composed of two parts: Part 1: The symbol of for welding, "H"; Part 2: Notations for designations of various s for welding. Where, the quality carbon structural, alloy structure and stainless shall respectively conform to provisions in 3.3.1, and Cold rolled electrical The cold rolled electrical is divided into grain-oriented electrical and non-oriented electrical, whose designation is generally composed of three parts: Part 1: The number which is 100 times of the material nominal thickness (unit: mm); Part 2: The symbol of ordinary grade grain-oriented electrical, "Q", the symbol of high permeability grade grain-oriented electrical, "QG" or the symbol of non-oriented electrical, "W"; Part 3: As for the grain-oriented electrical, it is 100 times of the maximum specific total loss (in W/kg) of products with the magnetic polarization of 1.7T, the frequency of 50Hz and with the corresponding thickness; as for the non-oriented electrical, it is 100 times of the maximum specific total loss (in W/kg) of products with the magnetic polarization of 1.5T, the frequency of 50Hz and with the corresponding thickness. For example: As for the ordinary-grade grain-oriented electrical with the nominal thickness of 0.30 mm, specific total loss (P 1.7/50 ) of 1.30W/kg, its designation is 30Q130. As for the high permeability grade grain-oriented electrical with the nominal thickness of 0.30 mm, specific total loss (P 1.7/50) of 1.10W/kg, its designation is 30QG110. As for the non-oriented electrical with the nominal thickness of 0.50mm, specific total loss (P1.5/50) of 4.0W/kg, its designation is 50W Electromagnetic pure iron The designation of the electromagnetic pure iron is generally composed of three parts: Part 1: The symbol of the electromagnetic pure iron, "DT"; Part 2: Arabic numerals, which express the serial number of different designations; Part 3: According to different electromagnetic performance, respectively adopt the quality grade to express the symbol "A", "C", "E" Pure iron for raw material The designation of pure iron for raw material is generally composed of two parts: Part 1: The symbol of the pure iron for raw material, "Y"; Part 2: Arabic numerals, which express the serial number of different designations High resistance alloys for electrical heating The designation of the high resistance alloys for electrical heating is expressed by the chemical element symbols specified in Table 1 and Arabic numerals. Notations for designations are the same with those of stainless and heat-resisting (as for the nickel-chromium alloy, the carbon content is not indicated). For example: As for the alloy (the rest is iron) with the chromium content of 18.00%~21.00%, nickel content of %~37.00 % and carbon content not greater than 0.08%, its designation is expressed as "06Cr20Ni35". 12