The Chinese version of standards hasprecedence to their English translations which are only for internal reference. 本英文版为内部资料，仅供参考，以中文 GB Trade Standards of the People's Republic of China 中华人民共和国国家标准 GB/T 699699-1999 Quality Carbon Structural Steels 优 质 碳 素 结 构 钢 Issued on 1 Nov. 1999 Executed since 1 Aug. 2000 1999-11-01 发布 2000-08-01 实施 ISSUED BY THE STATE BUREAU OF QUALITY TECHNICAL SUPERVISION 国家质量技术监督局 发布 1 BUREAU — The phosphorus and sulfur contents and macroscopic structure of steels are classified into three grades based on the metallurgical quality. — The range of carbon content for designations below 40 (with exception of 08F) is narrowed by 0. 80 and 85 steels is changed from "water cooling" to "oil cooling". dimensions and allowance shall be in accordance with the stipulations in standard GB/T 702-1986 or GB/T 908-1987.01%.GB/T 699-1999 Foreword This standard is a revision on GB/T 699-1998 "Specifications for Quality Carbon Structural Steels". — Marking symbols of steel products and unified numerical representation for various designations are added. — For steels delivered in the hot-rolled or hot forged state. The applicable scope is extended to such extent that quality carbon structural steels with diameter or thickness greater than 250mm may be supplied. The current revision of this standard has made modifications in respect of the following items: — — The name of standard is changed to "Quality carbon structural steels". the mechanical properties may be exempted from inspection if the supplier can guarantee the conformance. 2 . — In note 2 of Table 3. Th size. — — The chapter of "Order Information" is added. The acceptable grading of non-metallic inclusions is cancelled. This standard shall replace GB/T 699-1988 "Specifications for Quality Carbon Structural Steels" since its implementation. — — The "fracture" test is cancelled. the quench cooling medium for designation 75. Shanghai Pugang Group Corporation. This standard is prepared mainly by the Information Standard Institute of the Ministry of Metallurgical Industry. Sun Ping. and Handan Iron and Steel Corporation. 3 . Main draftsmen of this standard are: Luan Yan. Chen Changxi. Tang Yifan. This standard shall be under the jurisdiction of the National Technical Committee of Steel Standardization. Zhao Gaunxin This standard was initially issued in January 1965 and revised for the first time in February 1988.This standard is proposed by the State Bureau of Metallurgical Industry.. Tang Zhibai. Ltd. Chongqing Special Steel Co. Daye Special Steel Co. Teng Changling.. At the time of publication of this standard. GB/T 222-1984 Method for sampling of specimens for chemical analysis of steels and allowance for chemical composition of finished products GB/T 224-1987 Method for decarburized layer depth test of steels GB/T 226-1991 Method for acid attack test of macroscopic structure and imperfection of steels GB/T 228-1997 Method for tensile test of metals GB/T 229-1994 Metallic Material . The designations and chemical composition as specified in this standard is also applicable to steel ingots. technical requirements. This standard is applicable to quality carbon structural steel bars with diameter or thickness not greater than 250mm. marking and quality certificates of hot rolled or forged quality carbon structural steels. Those with diameter or thickness greater than 250mm may also be supplied as agreed between the buyer and the supplier. All standards shall be subject to amendment and revision. 1999 4 of August 1. 2 Normative References Provisions from the following standards shall form part of this standard by being cited herein. packaging. dimensions. the revisions of these standards as shown are valid. test methods. dimensions.National Standard of the People's Republic of China GB/T 699-1999 Quality carbon structural steels Substitute for GB/T 699-1988 ———————————————————————————————————————— 1 Scope This standard defines the size. weight and allowance of hot rolled round and square steels ———————————————————————————————————————— To be implemented as Approved by the State Bureau of Quality Technical Supervision on November 1. inspection rules. steel billets and their manufactures.Charpy notch impact test GB/T 231-1984 Method for Brinnel hardness test of metals GB/T 233-1982 Method for upsetting test of metals GB/T 702-1986 Size. 2000 . weight and allowance. and all users of this standard should probe into the possibility of applying the updated revisions of the following standards. markings and quality certificates of profile steels GB/T 2975-1998 Steel and steel products . packaging.Determination of content of non-metallic inclusion Micrographic method using standard diagrams GB/T 17616-1998 Unified numbering system for designations of iron.Determination of microstructure GB/T 15711-1995 Steel products . weight and allowance of forged round and square steels GB/T 1979-1980 Grading diagrams for evaluation of macroscopic structural imperfections of structural steels GB/T 2101-1989 General stipulations on acceptance. 3 Order Information Contracts concluded or purchase orders placed in compliance with this standard should contain ： the following information ） ； b）Description of product； c）Designations or unified numerical code； d）Weight (quantity) of delivery； a Standard code number 5 . steel and alloy GB/T 13299-1991 Steel .— ———————————————————————————————————————— GB/T 699 1999 GB/T 908-1987 Size.General technical delivery requirements YB/T 5148-1993 Method for the test of mean grain fineness of metals See Annex A (Annex to the Standard) for normative references for chemical analysis methods of various elements in steel. medium and low alloy steel GB/T 6397-1986 Specimens for tensile test of metals GB/T 7736-1987 Ultrasonic inspecting method for macro-structure and imperfection of steel GB/T 10561-1989 Steel .Methods for acid etch test of tower sample GB/T 17505-1998 Steel and steel products . dimensions.Location and preparation of test specimens for mechanical testing GB/T 4336-1984 Method for photoelectric emission spectroscopic analysis of carbon steel. dimensions and allowance of forged round and square steels should comply with relevant stipulations in GB/T 908. 6 .4.2 The size. Specific requirements should be clearly stated in the contract.2 Steel material is classified into two categories according to the processing method used: a) Steel for pressed work UP Steel for hot pressed work UHP Steel for upsetting work UF Steel for cold drawn billet UCD b) Steel for cutting work UC 5 Size. Weight and Allowance 5.8)； l）Special requirements (where required. dimensions and allowance of hot rolled round steels and square steels should comply with relevant stipulations in GB/T 702. 5.10)； GB/T 699—1999 ———————————————————————————————————————— e Class of accuracy for specification and size 4 Classification and Code 4.7)； k）Decarburized layer (where required.5)； j）Non-metallic inclusion (where required. as per 6.） ； f）Processing method used； g）State of delivery； h）Impact test (where required. as per 6. as per 6. Specific requirements should be clearly stated in the contract. as per 6. Dimensions.1 Steel material is classified according to its metallurgical quality as follows: Quality Steel Premium-grade Quality Steel A Special-grade Quality Steel E 4. as per 6.1 The size.1)； i）Upsetting test (where required. 17~0.39 0.37 0.65 0.25 0. the lower limit of manganese content is 0.80 0.05~0.17~0.50~0.35~0.22~0.25 0.37 0.37 0.80 0. unified numerical code and chemical composition (smelting analysis) of steels should comply with Table 1.60 0.37 0.65 0.25 0.30 0.50~0.02%~0. 6.25 13 U20502 50 0.10%.07%.50~0.1 Sulfur and phosphorus contents of steels should comply with Table 2.30 0. 6 Technical Requirements 6.60%. In this case the designation of the steel is 08Al.5 For aluminum deoxidization smelted killed steel for 08 steels.25 14 U20552 55 0.50~0.25 0.13 3 U20150 15F 0.30 0.80 0.17~0.17~0.25 0.13 6 U20152 15 0.17~0.17~0.15%.37 5 U20102 10 0. 6.25 10 U20352 35 0.12~0.80 0. the sulfur and phosphorus contents should comply with the requirements of steel wire standards.20%.25 0.35~0.55 0.1.25 0.30 0.30%. the silicon content should not be higher than 0.42~0.80 0.25 15 U20602 60 0.5.17~0.47~0.07 ≤ 0.30 0.12~0.50 0.03% and the aluminum content should be 0. the copper content should not be higher than 0.37 0.35~0.17~0.37 0.25 0.25 0.30 0.25 0.1.1.4 The manganese content of 35~38 steels for lead-bath quenched steel wires should be 0.50 0.20%.34 0.1.25~0.25 0. 6.07 4 U20082 08 0.25~0.50 0.80 0. Unified numerical code ，% Chemical composition Designation C Si 1 U20080 08F 0.30 0.80 0.50~0.37 0.25 0.18 ≤ 0.11 2 U20100 10F 0.1 Designation.44 0.1.29 0.30 0.57~0. 6.25 0.35~0.37 0.25 0.27~0.10 0.50~0.17~0. 6.52~0.25 11 U20402 40 0.65 0.1. the chromium content should not be higher than 0.37 0. dimensions and allowance of steels with other cross-sections should comply with relevant stipulations in corresponding standards.17~0.50~0.25 9 U20302 30 0.15 0.1.25 12 U20452 45 0.05~0.30 0.11 0.25~0.30 0.25%.37 0.37~0.25 0.07~0.17~0.1.3 The copper content of steels for hot pressed work should not be higher than 0.1.3 The size.1. — ———————————————————————————————————————— GB/T 699 1999 Table 1 No.17~0.15 0.10 0.25 0.2 The allowable copper content of steels smelted with steel scrap should not be higher than 0.65 0.07~0.30%~0.65 0.17~0.30 0. the nickel content should not be higher than 0.1.50~0.25 7 .1 Designations.30 0.37 0.03 ≤ 0.18 7 U20202 20 8 U20252 25 Mn Cr Ni Cu Not higher than 0.50 0.30 0.32~0. Code and Chemical Composition 6.25 0.23 0.80 0.30 0.30 0.25 0. 17~0.17~0.50~0.37 0.00 0.37 0.70~1.20 0.37 0.32~0.37 0.17~0.56 0.17~0.1.25 0.27~0.70 0.30 0. the end of the designation number is "F" (the last digit of the unified numerical code being "0").37 0.25 0.03%.00 0.62~0.75 0.30 0.30 0.17% may be supplied.2 The allowance for chemical composition of steel material (or billets) should comply with the stipulation in Table 2 of GB/T 222-1984.48~0.17~0.25 0.12~0.72~0.6 The silicon content of rimming steel for cold punch pressing should not be higher than 0.30 0.17~0. If the supplier can guarantee the conformance.30 0.37 0.75 0.25 28 U21502 50Mn 0.70~1.00 0.50 0.8 As agreed between the buyer and the supplier.25 0.25 0.90~1.50~0.17~0. the end of the designation number is "b" (the last digit of the unified numerical code being "1"). 6. In case of premium-grade quality steel.30 0.1.30 0.25 30 U21652 65Mn 0.37 0.30 0.00 0.30 0.85 0.50~0.020 8 .17~0.25 0.17~0.80 0.29 0.035 0.25 0.42~0.17~0.1.17~0.25 0.25 25 U21352 35Mn 0.25 0.025 0.82~0.62~0. % Quality steel 0.70~1.50~0.30 0. 6.00 0.34 0.37 0.57~0.00 0.70 0.17~0.22~0.65 0.30 0.25 0.030 Special-grade quality steel 0.37 0.44 0.25 31 U21702 70Mn 0.25 19 U20802 80 0.20 0. the analysis may be omitted.30 0.77~0. semi-killed steels with silicon content not higher than 0.23 0.37 0.008%.17~0.37 0.37 0.30 0.17~0.90~1.80 0. in case of special-grade quality steel.25 21 U21152 15Mn 0.00 0.25 29 U21602 60Mn 0.18 0.37~0.25 24 U21302 30Mn 0.80 0.17~0. 6.80 0.39 0.50~0.035 Premium-grade quality steel 0.1.70~1.25 0.1. Table 2 P Group S Not higher than.25 0. — ———————————————————————————————————————— GB/T 699 1999 6.25 0.00 0.030 0.25 22 U21202 20Mn 0.37 0.80 0.80 0.1.25 20 U20852 85 0. for rimming steel.16 U20652 65 0.17~0.1.25 Note: Those listed in Table 1 are quality steels.70~1.25 0. letter "E" shall be added to the end of the designation number (the last digit of the unified numerical code to be changed to "6").67~0. letter "A" shall be added to the end of the designation number (the last digit of the unified numerical code to be changed to "3").25 18 U20752 75 0.70~1.25 0.25 27 U21452 45Mn 0.25 17 U20702 70 0.37 0. for 08~25 steels.37 0. for semi-killed steel.00 0.25 0.70~1.37 0.17~0.70~1.30 0.25 23 U21252 25Mn 0.25 26 U21402 40Mn 0.70~1.7 The nitrogen content of steels smelted in oxygen-blown converters should not be higher than 0.30 0. with grade numbers of 08b~25b.30 0.67~0.90 0. 6. 6. It may also be delivered in the heat treated (annealed.4.1 The longitudinal mechanical properties of steel material obtained by testing the specimen made with heat-treated (normalized) work blank (excluding impact absorbed work) should comply with the stipulation in Table 3. the impact absorbed work of 25~50 and 25Mn~50Mn steels obtained by testing the specimen made with heat treated (quenched + tempered) work blank should comply with the stipulation in Table 3 Round steels with diameter smaller than 16mm and square or flat steels with thickness not greater than 12mm shall not be subject to the impact test. the smelting method shall be chosen by the manufacturer of its own accord. the result of the sampling test should comply with the stipulation in Table 3. For that with cross-section greater than 80mm.2 Smelting Method Unless otherwise specified in the contract.4.3 State of Delivery Steel material is normally delivered in the hot rolled or hot forged state. For the hardness of non-annealed steel. the result of the sampling test should comply with the stipulation in Table 3. Where steel material with size larger than 120mm to 250mm is re-forged to test piece sized between 90mm and 100mm. For steel material delivered in the hot rolled or hot forged state. normalized or high temperature tempered) if the buyer so requests and if so stated in the contract. 6.4. 6. the after-breaking elongation and percentage reduction of section are allowed to be lower than those — ———————————————————————————————————————— GB/T 699 1999 specified in Table 3 by 2% (absolute) and 5% (absolute) respectively. the tests may be omitted. if the supplier can guarantee the conformance.3 The hardness of steel material for cutting work or for cold drawn material in the delivery state should comply with the stipulation in Table 3.4 Mechanical Properties 6.6. if the supplier can guarantee the conformance. the test may be omitted. Table 3 9 . Where steel material with size larger than 80mm to 120mm is re-forged to test piece sized between 70mm and 80mm. The hardness indexes after high temperature tempering and normalization shall be determined by agreement between the supplier and the buyer. As required by the buyer.2 The mechanical properties shown in Table 3 are only applicable to steel material with cross-section size not greater than 80mm. Proposed heat mm ℃ Mechanical Properties Hardness of steel material in delivery state Tempering blank size Quenching Specimen Normalization No. Designation treatment. σb σs δ5 ψ AKU2 MPa MPa % % J HBS10/3 Non-heat Not less than treated steel 000 Annealed steel 1 08F 25 930 295 175 35 60 131 2 10F 25 930 315 185 33 55 137 3 15F 25 920 355 205 29 55 143 4 08 25 930 325 195 33 60 131 5 10 25 930 335 205 31 55 137 6 15 25 920 375 225 27 55 143 7 20 25 910 410 245 25 55 156 8 25 25 900 870 600 450 275 23 50 71 170 9 30 25 880 860 600 490 295 21 50 63 179 10 35 25 870 850 600 530 315 20 45 55 197 11 40 25 860 840 600 570 335 19 45 47 217 187 12 45 25 850 840 600 600 355 16 40 39 229 197 13 50 25 830 830 600 630 375 14 40 31 241 207 14 55 25 820 820 600 645 380 13 35 255 217 10 . σb σs δ5 ψ AKU2 MPa MPa % % J HBS10/3 Non-heat Not less than treated steel 000 Annealed steel 15 60 25 810 675 400 12 35 255 229 16 65 25 810 695 410 10 30 255 229 17 70 25 790 715 420 9 30 269 229 18 75 specimen 820 480 1 080 880 7 30 285 241 19 80 specimen 820 480 1 080 930 6 30 285 241 20 85 specimen 820 480 1 130 980 6 30 302 255 21 15Mn 25 920 410 245 26 55 163 22 20Mn 25 910 450 275 24 50 197 23 25Mn 25 900 870 600 490 295 22 50 71 207 24 30Mn 25 880 860 600 540 315 20 45 63 217 187 25 35Mn 25 870 850 600 560 335 18 45 55 229 197 26 40Mn 25 860 840 600 590 355 17 45 47 229 207 27 45Mn 25 850 840 600 620 375 15 40 39 241 217 28 50Mn 25 830 830 600 645 390 13 40 31 255 217 29 60Mn 25 810 695 410 11 35 269 229 30 65Mn 25 830 735 430 9 30 285 229 31 70Mn 25 790 785 450 8 30 285 229 11 . Designation treatment.— ———————————————————————————————————————— GB/T 699 1999 Table 3 Proposed heat mm ℃ Mechanical Properties Hardness of steel material in delivery state Tempering blank size Quenching Specimen Normalization No. inclusion.1 There should be no shrinkage cavity. No fissure or fracture shall exist on the specimen after the upsetting. The height of specimen after hot upsetting shall be as much as 1/3 of that of the original specimen.5 2.6.5 Special-grade quality steel 2. that for tempering is not less than 1 hour.1 Steels for upsetting work shall be subject to upsetting test and either hot upsetting or cold upsetting should be clearly stated in the contract. it is allowable to substitute ultrasonic test or other nondestructive tests specified in standard GB/T 7736 for the macroscopic test.5 2.2 For steel material with size larger than 80mm that requires hot upsetting.0 6. The proposed temperature holding time for normalization as listed in the table is not less than 30 minutes with air cooling.6. Such imperfections as subsurface inclusion not exceeding the allowable depth for surface imperfection are allowed on the steel material for cutting work. For steel material with diameter or thickness less than 25mm. heat treatment is conducted on the specimen blank with the same cross-section size as that of finished products.0 Premium-grade quality steel 2. — ———————————————————————————————————————— GB/T 699 1999 6. 80 and 85 steels and water cooling for other steels.2 Pickled macroscopic structure should comply with the stipulation in Table 4. if the supplier can guarantee the conformance. 6. 2. the height of specimen after cold upsetting shall be as much as 1/2 of that of the original specimen. the test may be omitted. 6.6. that for quenching is not less than 30 minutes with oil cooling for 75.0 2.5.6 Macroscopic Structure 6.0 2. blister. Table 4 Quality grade General poriness Central poriness Ingot mold aliquation Level (not greater than) Quality steel 3.0 3. skull patch or fish eye visible to the naked eyes on the cross-sectional pickled macroscopic structure specimen of killed steel material.0 3.3 If the supplier can guarantee the conformance of macroscopic test. 12 . or that with size larger than 30mm that requires cold upsetting.5.Notes: 1. crack. 6.5 Upsetting 6. For steel material with diameter or side length larger than 140mm. folding or inclusion visible to the naked eyes on the surface of steel material for pressed work.9. Table 6 Nominal size of steel material (diameter or depth) < 80 80~140 mm Allowable depth of imperfection removal 1/2 of nominal size allowance of steel material Nominal size allowance of steel material 13 .2mm in existence. The buyer should indicate the group in the contract. 6. Any of the above imperfections should be removed to such extent that the removed depth as calculated from the surface of steel material is in compliance with the stipulation in Table 6.30%.8 Decarburized Layer When testing the decarburized layer of steels with nominal carbon content higher than 0.9 Surface Quality 6. — ———————————————————————————————————————— GB/T 699 1999 Table 5 mm Group Allowable total depth of decarburized layer (not higher than) Group I 1.2 Local imperfections with depth not exceeding the stipulation in Table 7 as calculated from the nominal size of steel material are allowable on the surface of steel material for cutting work. as required by the buyer. no more than 2 places with maximum removal depth are allowed on the same cross section. rolling skin.5%D Note: D is the nominal diameter or thickness of steel material 6.6.9.1 There should be no crack. The width for removal should not be less than 5 times the depth. non-metallic inclusions may be tested with the acceptable levels to be defined by agreement between the buyer and the supplier. It is allowable to have very few fine scratches.0%D Group II 1. the total depth of decarburized layer on each side (ferrite + transition layer) should comply with the stipulation in Table 5. 6. impression marks and pork marks with size not exceeding half of the size allowance as calculated from the actual size and fine crackles with depth within 0.7 Non-metallic Inclusion As required by the buyer. d) To test the microstructure of steel. No. Test item Quantity of samples Location for sampling Test method 1 Chemical composition 1 GB/T 222 GB/T 223 GB/T 4336 2 Tensile test 2 Different pieces of steel material GB/T 228 GB/T 2975 14 . e) To test the hair line seams with telescoping (tower) specimen. c) To test the grain fineness of steel.10 Special Requirements As required by the buyer and so agreed between the buyer and the supplier. b) Steel bars with diameter or thickness larger than 250mm. steel material meeting the following special requirements may be supplied: a) To narrow or modify the range of chemical composition specified in Table 1. g) To make V-notched impact test (the indexes to be agreed between the buyer and the supplier). Table 8.>140 ~ 200 5% of nominal size of steel material > 200 6% of nominal size of steel material Table 7 Nominal size of steel material (diameter or thickness) < 100 ≥ mm Allowable depth of local imperfection (not greater than) Negative allowance of nominal size of steel material Allowance of nominal size of steel material 100 — ———————————————————————————————————————— GB/T 699 1999 6. 7 Test Methods Test methods for each and every batch of steel material should comply with the stipulation in Table 8. h) Other. f) To make the mechanical properties indexes stricter. GB/T 6397 3 Hardness test 3 Different pieces of steel material GB/T 231 4 Impact test 2 Different pieces of steel material GB/T 229 5 Upsetting test 2 Different pieces of steel material GB/T 233 6 Macroscopic structure 2 Different pieces of steel billet or steel GB/T 226 material equivalent to the end of steel GB/T 1979 ingot 7 Telescoping (tower) hair line seams 2 Different pieces of steel material GB/T 15711 8 Decarburization 2 Different pieces of steel material GB/T 224 (metallo-graphic) 15 . 8.2 Batch Forming Rules Steel material should be inspected and accepted batchwise.3 Quantity and Location for Sampling The quantity and location for sampling of steel material should comply with the stipulation in Table 8.1 The quality of steel material shall be inspected and accepted by the quality technical supervision department of the supplier.— ———————————————————————————————————————— GB/T 699 1999 Table 8.4.4. 8. Each batch consists of steel material with the same heat (furnace) number.1 Inspection and Acceptance 8. dimensions Piece by piece On the whole of steel material Caliper.2 If the supplier can guarantee the conformance of the steel material.1 The re-inspection and judging rules shall be in compliance with relevant stipulations in 8. No. the same size.2 The supplier must ensure that the steel material delivered complies with the stipulations of this standard or of the contract.1. 8.1. 8.3 of standard GB/T 17505-1998. it is allowable to substitute billet for material or large pieces for small ones with respect to the test results of 16 . micrometer 14 Visual aspects Piece by piece On the whole of steel material Visual inspection 8 Test Rules 8. the same working method.4 Re-inspection and Judging Rules 8.3. the same delivery state (or the same heat treatment system/furnace lot) and the same surface state. Test item Quantity of samples Location for sampling Test method 9 Grain fineness 1 Any piece of steel material YB/T 5148 10 Non-metallic inclusion 2 Different pieces of steel material GB/T 10561 11 Microstructure 2 Different pieces of steel material GB/T 13299 12 Ultrasonic test 2 On the whole of steel material GB/T 7736 13 Size. 8.4. The buyer is entitled to make inspection or acceptance to any of the test items defined in this standard or the contract if necessary. — ———————————————————————————————————————— GB/T 699 1999 9 Packaging.19 .12 . mechanical properties and non-metallic inclusion for the steel material or ingots with the same heat (furnace) number. steel and alloy ― The reduced molybdosilicate spectrophotometric method for the determination of acid-soluble silicon content Methods for chemical analysis of iron. steel and alloy ― The determination of copper content by neocuprone-photometric 17 .3 – 1988 GB/T 223.Methods for Chemical Analysis GB/T 223.10 . steel and alloy ― The diantipyryl-methane phosphomolybdic acid gravimetric method for the determination of phosphorus content Methods for chemical analysis of iron.5 – 1997 GB/T 223. steel and alloy ― The determination of chromium content by diphenyl carbazide photometric method after separation with sodium carbonate Methods for chemical analysis of iron.1991 GB/T 223.macroscopic test. steel and alloy ― The sodium thiosulfate separation iodimetric method for the determination of copper content Methods for chemical analysis of iron. steel and alloy ― The determination of aluminum content by chrome azurol S photometric method after separation with cupferron Methods for chemical analysis of iron.1991 GB/T 223. Marking and Quality Certificate Packaging.1994 GB/T 223.1991 GB/T 223.18 .1989 Methods for chemical analysis of iron. marking and quality certificates of the steel material should comply with the stipulations of GB/T 2101.11 . Annex A Annex to the Standard Normative References . steel and alloy ― The determination of chromium content by persulfate oxdation volumetric method Methods for chemical analysis of iron. 59 .1997 Methods for chemical analysis of iron. steel and alloy ― The indigo photometric method for the determination of nitrogen content after distillation separation Methods for chemical analysis of iron.58 .The dimethylglyoxime spectrophoto method for the determination of nickel content Methods for chemical analysis of iron.GB/T 223. steel and alloy ― The determination of manganese content by sodium arsenite – sodium nitrite titration method Methods for chemical analysis of iron. steel and alloy ― The determination of copper content by flame atomic absorption spectrophotometry Methods for chemical analysis of iron. steel and alloy ― The determination of nickel content by flame atomic absorption spectrophotometry Methods for chemical analysis of iron.60 .1987 GB/T 223.37 .1994 method Methods for chemical analysis of iron. steel and alloy ― The neutral titration method for the determination of nitrogen content after distillation separation — ———————————————————————————————————————— GB/T 699 1999 GB/T 223. steel and alloy ― The dimethylglyoxime spectrophotometric method for the determination of nickel content Methods for chemical analysis of iron.1987 GB/T 223. steel and alloy ― The perchloric acid dehydration gravimetric method for the determination of silicon content 18 .36 . steel and alloy ― The determination of phospgorus content by antimonium-Phosphorus-Molybdium-blue photometric method Methods for chemical analysis of iron.54 .1987 GB/T 223.53 .1989 GB/T 223.24 .1987 GB/T 223.1994 GB/T 223.1994 GB/T 223.23 . steel and alloy ― The extraction separation . 1997 Methods for chemical analysis of iron. steel and alloy ― The determination of phosphorus content by ammonium molybdo-phosphate volumetric method Methods for chemical analysis of iron. steel and alloy ― Aluminum oxide stratography .61 .1988 GB/T 223.67 . steel and alloy ― The potassium iodate titration method after combustion in the pipe furnace for the determination of sulfur content Methods for chemical analysis of iron. steel and alloy ― The volumetric method after combustion in the pipe furnace for the determination of carbon content Methods for chemical analysis of iron.71 . steel and alloy ― The determination of phosphorus content by butyl acetate extraction photometric method Methods for chemical analysis of iron.barium sulfate gravimetric method for the determination of sulfur content 19 .1988 GB/T 223.1997 GB/T 223.62 .72 .68 .1997 GB/T 223. steel and alloy ― The determination of sulfur content methylidyne blue photometric method after reduced distillation Methods for chemical analysis of iron.1988 GB/T 223.64 .69 .1989 GB/T 223.GB/T 223. steel and alloy ― The gas-volumetric method after combustion in the pipe furnace for the determination of carbon content — ———————————————————————————————————————— GB/T 699 1999 GB/T 223.1988 GB/T 223.63 .1991 Methods for chemical analysis of iron. steel and alloy ― The determination of manganese content by flame atomic absorption spectrometric method Methods for chemical analysis of iron. steel and alloy ― The determination of manganese content by sodium (potassium) permanganate photometric method Methods for chemical analysis of iron. ————————— 20 .