16-GB-T 8162-1999-Seamless Steel Tubes for Structural Purposes

GBICS 77.140.75 H 48 National Standard of the People's Republic of China 中华人民共和国国家标准 GB/T 8162-2008 Replace GB/T 8162-1999 Seamless Steel Tubes for Structural Purposes 结构用无缝钢管 Issued on August 19, 2008 Jointly issued by Implemented on April 1, 2009 the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China and Standardization Administration Of The People's Republic of China. Forwards This national standard is not equivalent to EN 10297-1: 2003 "Seamless Circular Steel Tubes for Mechanical and General Engineering Purposes-Technical Delivery Conditions". This national standard replaces GB/T 8162-1999 "Seamless Steel Tubes for Structural Purposes", while comparing with it, this Standard has the following major variation: ——add order content; ——modify allowable deviation of the dimension; ——add requirements of the full-length tortuosity factor; ——add requirements of the terminal shear drag; ——cancel marking illustrations; ——add steel grades; ——cancel requirements of the expanding test; ——add negotiation provisions of the nondestructive test This national standard is proposed by China Iron & Steel Association. This national standard is under jurisdiction of China Steel Standardization Technical Committee. This Standard is mainly prepared (organizations) by Angang Steel Company Limited, Pangang Group Chengdu Iron & Steel Co., Ltd. and Hunan Hengyang Steel Tube Group Co., Ltd. This Standard is mainly prepared by (staffs): ZHANG Huixuan, ZHANG Peng, PIAO Zhimin, LI Qi, ZHAO Bin and LI Zhi. This national standard replaces the previous versions: ——GB/T 8162-1987, GB/T 8162-1999 I Contents Forwards ........................................................................................................................................... I 1. Scope.............................................................................................................................................1 2. Normative References...................................................................................................................1 3. Order content ................................................................................................................................4 4. Dimension, shape and weight .......................................................................................................4 4.1 Outside diameter and wall thickness...................................................................................4 4.2 Allowable deviation of outside diameter and wall thickness ..............................................4 4.3 Length .................................................................................................................................5 4.4 Tortuosity factor ..................................................................................................................6 4.5 Noncircularity and wall unevenness ...................................................................................6 4.6 Terminal shape ....................................................................................................................6 4.7 Weight .................................................................................................................................7 5. Technical requirements .................................................................................................................7 5.1 Grade of steel and chemical composition ...........................................................................7 5.2 Manufacturing method ........................................................................................................8 5.3 Delivery state ......................................................................................................................8 5.4 Mechanical properties .........................................................................................................9 5.5 Technical properties ..........................................................................................................13 5.6 Surface quality ..................................................................................................................13 5.7 Nondestructive test............................................................................................................14 6. Test method .................................................................................................................................14 7. Inspection rules ...........................................................................................................................15 8. Packaging, marking and quality certification..............................................................................15 II 8 Methods for Chemical Analysis of Iron. Scope This national standard specifies order content. test rules. technical requirements. Steel and Alloy. 2. Steel and Alloy. the Reduced Molybdosilicate Spectrophotometric Method for the Determination of Acid-soluble Silicon Content GB/T 223. the latest edition of the normative document is applicable to this national standard. the Diantipyrylmethane Phosphomolybdate Gravimetric Method for the Determination of Phosphorus ContentGB/T 223. any of these publications do not be applied.9 Iron Steel and Alloy-Determination of Aluminium Content-Chrom Azurol S Photometric Method GB/T 223. The Sodium Carbonate Separation-diphenyl Carbazide Photometric Method for the Determination of Chromium Content GB/T 223. size.3 Methods for Chemical Analysis of Iron.14 Methods for Chemical Analysis of Iron. Steel and Alloy. Steel and Alloy.12 Methods for Chemical Analysis of Iron. Steel and Alloy. GB/T 222 Permissible Tolerances for Chemical Composition of Steel Products GB/T 223. through reference in this text. Steel and Alloy.5 Methods for Chemical Analysis of Iron. the Sodium Fluoride Separation-EDTA Titration Method for the Determination of Aluminium Content GB/T 223.11 Methods for Chemical Analysis of Iron. constitute provisions of this national Standard. the Ammonium Ferrous Sulfate Titration Method for the Determination of Vanadium Content GB/T 223. subsequent amendments (excluding amending error in the text) to. For dated reference. Normative References The following standards contain provisions which. the 1 . test methods. the Ammonium Persulfate Oxidation Volumetric Method for the Determination of Chromium Content GB/T 223.Seamless Steel Tubes for Structural Purposes 结构用无缝钢管 GB/T 8162-2008 1. However.13 Methods for Chemical Analysis of Iron. For undated references. weight. packaging. shape. or revisions of. the parties whose enter into agreement according to these specifications are encouraged to research whether the latest editions of these references are applied or not. This Standard is applicable to seamless steel tubes for mechanical and general engineering structural purposes. marking and quality certificate of seamless steel tubes for structural purposes. Steel and Alloy. Steel and Alloy. Steel and Alloy. the Flame Atomic Absorption Spectrophotometric Method for the Determination of Copper Content GB/T 223.40 Methods for Chemical Analysis of Iron. Steel and Alloy.25 Methods for Chemical Analysis of Iron.18 Methods for Chemical Analysis of Iron. the Flame Atomic Absorption Spectrophotometric Method for the Determination of Nickel Content GB/T 223. the Thiocyanate Spectrophotometric Method GB/T 223. Steel and Alloy. the Sulphochlorophenol S Photometric Method for the Determination of Niobium Content GB/T 223. Steel and Alloy. Steel and Alloy.26 Iron Steel and Alloy-Determination of Molybdenum Content. the Dimethylglyoxime Spectrophotometric Method GB/T 223. Steel and Alloy. the Dimethylglyoxime Gravimetric Method for the Determination of Nickel Content GB/T 223.54 Methods for Chemical Analysis of Iron. the Perchloric Acid Dehydration Gravimetric Method for the Determination of Silicon Content GB/T 223. Steel and Alloy. the Sodium Thiosulfate Separation Iodimetric Method for the Determination of Copper Content GB/T 223. the Neutral Titration Method for the Determinaion of Nitrogen Content after Distillation Separation GB/T 223. the Indophenal Blue Photometric Methods for the Determination of Nitrogen Content after Distillation Separation GB/T 223.N-benzoy-N-phenylhydroxylamine Extraction Photometric Method for the Determination of Vanadium Content GB/T 223. the Reduced Molybdoantimonyl Phosphoric Acid Photometric Method for the Determination of Phosphorus Content GB/T 223.63 Methods for Chemical Analysis of Iron.37 Methods for Chemical Analysis of Iron Steel and Alloy. the Sodium (Potassium) Periodate Photometric Method for the Determination of Manganese Content GB/T 223. Steel and Alloy.58 Methods for Chemical Analysis of Iron.16 Methods for Chemical Analysis of Iron.66 Methods for Chemical Analysis of Iron.23 Iron Steel and Alloy-Determination of Nickel Content. the 2 . the Butyl Acetate Extraction Photometric Method for the Determination of Phosphorus Content GB/T 223. Steel and Alloy. the Ammonium Phosphomolybdate Volumetric Method for the Determination of Phosphorus Content GB/T 223.6l Methods for Chemical Analysis of Iron. Steel and Alloy. Steel and Alloy.64 Iron Steel and Alloyed-Determination of Manganese Content-Flame Atomic Absorption Spectrometric Method GB/T 223.62 Methods for Chemical Analysis of Iron. the Sodium Arsenite-sodium Nitrite Titrimetric Method for the Determination of Manganese Content GB/T 223.19 Methods for Chemical Analysis of Iron Steel and Alloy.53 Methods for Chemical Analysis of Iron.60 Methods for Chemical Analysis of Iron.59 Methods for Chemical Analysis of Iron. Steel and Alloy.43 Iron Steel and Alloy-Determination of Tungsten Content-Gravimetric Method and Spectrophotometric Method GB/T 223. Steel and Alloy. the Chromotropic Acid Photometric Method for the Determination of Titanium Content GB/T 223. the Neocuproine-chloroform Extraction Photometric Method for the Determination of Copper Content GB/T 223.36 Methods for Chemical Analysis of Iron. Thiocyanate-chlorpromazine Hydrochloride-Chloroform Extraction Photometric Method for the Determination of Tungsten Content GB/T 223. Steel and Alloy. MOD) GB/T 231.1 Metallic Materials-Brinell Hardness Test-Part 1: Test Method (GB/T 231. Steel and Alloy. ISO 8491: 1996. EQV) GB/T 244 Metallic Materials-Tube-Bend Test (GB/T 244-2008.1-2002. the Gravimetric Method after Combustion in the Pipe Furnace for the Determination of Carbon Content GB/T 223. the Combustion Gravimetric/gas-Volumetric Method for the Determination of Combined Carbon Content GB/T 223. IDT) GB/T 228 Metallic Materials-Tensile Testing at Ambient Temperature (GB/T 228-2002.76 Methods for Chemical Analysis of Iron. ISO 8492: 1998. ISO 148-1: 2006. ISO 9303: 1989. ISO 9304: 1989. MOD) GB/T 7735 Steel Tubes—the Inspection Method on Eddy Current Test (GB/T 7735-2004. ISO 10153: 1997. IDT) GB/T 699 Quality Carbon Structural Steels GB/T 1591 Low-alloy High-tensile Structural Steel GB/T 2102 Acceptance Packing.75 Iron Steel and Alloy-Determination of Boron Content-Methanol Distillation-Curcumin Photometric Method GB/T 223. Steel and Alloy-Curcumin Spectrophotometric Method for the Determination of Boron Content (GB/T 223.78-2000. IDT) GB/T 246 Metal materials—Tube—Flattening test (GB/T 246-2007. Steel and Alloy.74 Methods for Chemical Analysis of Iron. Steel and Alloy. MOD) GB/T 12606 Steel Tubes-The Testing Method of Magnetic Flux Leakage (GB/T 126063 . the Gas-Volumetric Method after Combustion in the Pipe Furnace for the Determination of Carbon Content GB/T 223. Steel and Alloy.72 Iron Steel and Alloy-Determination of Sulfur Content-Gravimetric Method GB/T 223. the Potassium Iodate Titration Method after Combustion in the Pipe Furnace for the Determination of Sulfur Content GB/T 223. eqv ISO 377: 1997) GB/T 3077 Alloy Structure Steels GB/T 4336 Standard Test Method For Spark Discharge Atomic Emission Spectrometric Analysis of Carbon and Low-alloy Steel (Routine Method) GB/T 5777 Seamless Steel Pipe and Tubing-methods for Ultrasonic Testing (GB/T 5777-2008.69 Methods for Chemical Analysis of Iron. the Flame Atomic Absorption Spectrometric Method for the Determination of Vanadium Content GB/T 223.78 Methods for Chemical Analysis of Iron. eqv ISO 6892: 1998) GB/T 229 Metallic Materials—Charpy Pendulum Impact Test Method (GB/T 229-2007. ISO 6506-1: 1999. Marking and Quality Certification of Steel Pipe GB/T 2975 Steel and Steel Products--Location and Preparation of Test Pieces for Mechanical Testing (GB/T 2975.71 Methods for Chemical Analysis of Iron.67 Iron Steel and Alloy-Determination of Sulfur Content-Methylene Blue Spectrophotometric Method GB/T 223.68 Methods for Chemical Analysis of Iron.1998. Masses and Tolerances of Seamless Steel Tubes (GB/T 17395-2008. d) Dimensions. ISO 15351: 1999. IDT) GB/T 20123 Steel and Iron—Determination of Total Carbon and Sulfur Content Infrared Absorption Method after Combustion in an Induction Furnace (Routine Method) (GB/T 20123-2006. ISO 15350: 2000. g) Special requirement 4. ISO 1127: 1992. ISO 14284: 1996. ISO 9598: 1989) GB/T 17395 Dimensions.1 Outside diameter and wall thickness The outside diameter (D) and wall thickness (S) of steel tubes shall comply with the provisions of GB/T 17395-1998. Order content Contract or order ordering steel pipes according to this Standard shall include the following contents: a) Standard number. IDT) GB/T 20124 Steel and Iron—Determination of Nitrogen Content—Thermal Conductimetric Method after Fusion in a Current of Inert Gas (Routine Method) (GB/T 20124-2006. IDT) GB/T 20125 Low-Alloy Steel-Determination of Multi-element Contents-Inductively Coupled Plasma Atomic Emission Spectrometric Method 3. shape and weight 4. NEQ) GB/T 20066 Steel and Iron-Sampling and Preparation of Samples for the Determination of Chemical Composition (GB/T 20066--2006. e) Order quantity (total weight or total length). 4 . f) Delivery state. c) Grade of steel.1999. quality classification must be indicated while necessary. b) Product name. ISO 5252: 1991. eqv ISO 9402: 1989. Dimension.2 Allowable deviation of outside diameter and wall thickness 4. the steel tube with other outside diameters and wall thicknesses can be supplied.2. ISO 4200: 1991. Shapes. According to the requirements of the purchaser and through the mutual negotiation of both the purchaser and the supplier.1 The allowable deviation of outside diameter of the steel tube shall be in accordance with those specified in Table 1. 4. takes the larger value >102 ≤0. 5 .Table 1 Allowable Deviation of Outside Diameter of the Steel Tube Steel tube kinds Allowable deviation Hot rolling (extruding and expanding) steel tube ±1%D or ±0.2 The allowable deviation of wall thickness of the hot rolling (extruding and expanding) steel tube shall be in accordance with those specified in Table 2.15.5%S or ±0. takes the larger value >102 >0. take the larger value Cold drawing (rolling) steel tube ±1%D or ±0.10 12.05 ±15% S or±0.2.2.5% S 10% S +12. through the mutual negotiation of both the purchaser and the supplier and indicated in the contract. steel tube with allowable deviation of dimensions excluded of Table 1. Table 2 or Table 3.2.3.1 Usual length Usual length of the steel tube is 3000mm~12500mm.2 Scope length According to requirements of the purchaser.3 The allowable deviation of wall thickness of the cold drawing (rolling) steel tube shall be in accordance with those specified in Table 3.40.5%S 4. the steel tube may be delivered according to the cut length or multiple lengths. 4.2.50.40.1 According to requirements of the purchaser.4 According to the requirements of the purchaser. takes the larger value >102 >0.5% S 10% S diameter of steel tube Hot expanding steel tube — ±15%S 4. and the allowable deviation of the cut lengths shall comply with the following provisions: a) The cut length is no greater than 6000 mm.2 The cut length of steel tube shall be within the usual length scope.0. and indicated in the contract.3.3 Length 4. through the mutual negotiation of both the purchaser and the supplier. steel tube may be delivered according to the scope length.3.05~0. Table 3 Allowable Deviation of Wall Thickness of the Cold Drawing (rolling) Steel Tube Steel tube kinds Nominal wall thickness of steel tube Cold drawing (rolling) ≤3 Cold drawing (rolling) >3 in: mm Allowable deviation 15% S 10% S or ±0.3.30. The length scope shall be within the scope of usual length. 4.3 Cut-to-length and multiple lengths 4.3. and indicated in the contract. through the mutual negotiation of both the purchaser and the supplier.10 ±12.3. take the larger value 12.3. 4.5% S or±0. take the larger value in: mm 4. 10 0 mm. Table 2 Allowable Deviation of Wall Thickness Hot Rolling (Extruding and Expanding) Steel Tube in: mm Steel tube kinds Hot rolling (extruding) steel tube Hot rolling (extruding) steel tube Nominal outside S/D Allowable deviation ≤102 — ±12. 4.40. 1 The tortuosity factor of steel tube per meter shall be in accordance with those specified in Table 4. the noncircularity and wall unevenness of steel tube shall be no more than 80% of the outside diameter and wall thickness tolerances respectively.3.5 mm. 6 .6 Terminal shape 4. the steel tube with nominal outside diameter of greater than 60 mm.5% of the nominal outside diameter of steel tube.5 Noncircularity and wall unevenness According to the requirements of the purchaser.4 Tortuosity factor 4.5‰ of the total steel tube length.3.b) The cut length is greater than 6000 mm. 15 0 mm. the pipe terminal shear drag shall be no more than 1. b) The outside diameter is greater than 159 mm.3 Total multiple length of the steel tube shall be within the usual length. but the maximum outside diameter shall be no more than 6mm.4. the pipe terminal shear drag shall be no more than 2. 5 mm~10 mm.4. The shear drag of the steel tube sees Figure 1.5 >15~30 ≤2. 4.1 The steel tube with nominal outside diameter of no greater than 60 mm.6. 4. 10 mm~15 mm. 4. Table 4 Tortuosity Factor of Steel Tube Nominal wall thickness of steel tube /mm Tortuosity factor of per meter (mm/m) ≤15 ≤1.0 >30 or D≥351 ≤3. through the negotiation of both the purchaser and the supplier. 4.2 Full-length tortuosity factor of the steel tube shall be no greater than 1.0 4. and indicated in the contract. the full-length allowable deviation is 20 0 mm. and multiple lengths shall be set aside kerf surplus according to the following provisions: a) The outside diameter is no greater than 159 mm. through mutual negotiation of the purchaser and the supplier.7 Weight 4. B and C shall not be greater than 0. the deviation between theoretical weight and actual weight of the delivered steel tube shall comply with the following requirements: a) Unipivot steel tube: ±10%. 15.1 The steel tube shall be delivered according to the actual weight. 25. phosphine and sulfur content of steel with quality grade of A.1 The grade and chemical composition (heat analysis) of carbon constructional quality steel shall comply with the requirements of 10. 4. 35.1. 45. 20Mn and 25Mn specified in GB/T 699.7. b) Steel tube with minimum lot's weight of 10t:±7.6. 20.Figure 1 Shear Drag 4.1 Grade of steel and chemical composition 5. Calculation for theoretical weight of the steel tube complies with GB/T 17395 and the steel density is 7. Chemical composition (heat analysis) of the steel in grades of Q235 and Q275 shall be in accordance with those specified in Table 5. The grade and chemical composition (heat analysis) of the low-alloy high-tensile structural steel shall comply with GB/T 1591.2 Terminal kerf burr of the steel tube shall be removed. 5.5%.2 According to the requirements of the purchaser. or it may be delivered according to theoretical weight.030%. therein.85 kg/dm3. 4. The grade and chemical composition (heat analysis) of alloy structure steels shall comply with GB/T 3077.7. Technical requirements 5. and indicated in the contract. 7 . 20%.24 B ≤0. If the purchaser specifies some steel tube manufacturing process.1 Smelting process of steel The steel shall be smelted with electric arc furnace plus out-of-furnace refining or oxygen converter plus out-of-furnace refining method.22 B ≤0.4 — 0.1 The hot rolling (extruding and expanding) steel tube shall be delivered in hot rolling state or heat treatment condition. the steel may also be smelted by other method with higher requirements. and the allowable deviation of the chemical composition of the finished steel tube shall comply with GB/T 222.020 0.2 According to the requirements of the purchaser and through the mutual negotiation of both the purchaser and the supplier.025 ≥O.2.20 — — The content of residual elements Cr and Ni shall be no greater than 0.30%.030 — 0.2 Manufacturing method 5. it shall be indicated in the contract. 5.030 0.2 Manufacturing method of the tubular billet The tubular billet is made by continuous casting or hot rolling (forging).030 0.3 Delivery state 5.3.3 Manufacturing method of the steel tube The steel tube shall be made with hot rolling (extruding and expanding) or cold drawing (rolling) seamless method.030 0.015%. 8 .35 ≤1. Als≥0. If the purchaser requires delivery in heat treatment condition. the steel tube with other grades can be produced.1.17 D Q275 A ≤0. 5.20 ≤0.2. 5. 5. If the purchaser specifies some smelting process.025 0. 5.020 — ≤0.21 C D a ≤0.1. the smelting process shall be clearly indicated in the contract.35 C ≤1.Table 5 Chemical Composition (Heat Analysis) of Q235 and Q275 Steel Chemical composition (mass fraction)a/% Grade Quality grade C Si Mn P S Alt(Total aluminium)b No greater than Q235 A ≤0.025 0.030 — 0.2.025 ≥O.030 0.030 0. and the steel ingot may also be used as tubular billet directly. Through the mutual negotiation of the purchaser and the supplier.030 0. the manufacturing process shall be clearly indicated in the contract.3 When the purchaser requires product analysis. 5. and Cu content shall be no greater than 0.50 ≤0. b When analyzing Als (acid-soluble aluminium). 5.4. 9 .4. the cold drawing (rolling) steel tube may be delivered in cold drawing (rolling) state as well.4.2 Sample roughcast of alloy structure steel tube is heat-treated according to heat treatment system recommended in Table 7. low-alloy high-tensile structural steel or Q235 and Q275 steel tubes shall be in accordance with those specified in Table 6 in their delivery state.1 The tensile property of carbon constructional quality steel.it shall be clearly indicated in the contract. 5.3 The mechanical properties of steel tube delivered in cold drawing (rolling) state agreed by both the purchaser and the supplier.1 Tensile property 5. According to the requirement of the purchaser.1.4.1. 5. through the mutual negotiation of the purchaser and the supplier. 5.4 Mechanical properties 5.2 The cold drawing (rolling) steel tube shall be delivered in heat treatment condition.1.3. and indicated in the contract. and the longitudinal tensile property measured for the sample shall be in accordance with those specified in Table 7. Table 6 Mechanical Properties of Carbon Constructional Quality Steel. if yield strength cannot be measured.2 may be measured to replace ReL. the specified non-proportion extension intensity RP0. 10 . or Steel Tubes in Grades of Q235 And Q275 Grade Quality Tensile strength grade Rm/MPa Lower yield strength Post-breaking ReLa/MPa extensibility Wall thickness/mm ≤16 >16 30 A/% >30 No less than Impact test Absorbed energy Temperature /℃ KV2/J No greater than 10 — ≥335 205 195 185 24 — — 15 — ≥375 225 215 205 22 — — 20 — ≥410 245 235 225 20 — — 25 — ≥450 275 265 255 18 — — 35 — ≥510 305 295 285 17 — — 45 — ≥590 335 325 315 14 — — 20Mn — ≥450 275 265 255 20 — — 25Mn — ≥490 295 285 275 18 — — — — A B Q235 C 235 225 215 25 A — 415~540 275 265 255 22 D A B 390~570 295 275 255 22 20 B C 470~630 345 325 295 E A 18 B C 490~650 390 370 350 E A 18 B C 520~680 420 400 380 E +20 34 — — +20 460 440 420 17 34 — 20 -40 27 — — +20 34 -20 — 40 27 — — +20 34 -20 0 550~720 E a — -40 C D 27 — 0 19 D Q460 0 0 19 D Q420 — +20 0 21 D Q390 27 -20 A Q345 0 -20 C Q295 +20 D B Q275 375~500 -20 — 40 27 34 27 During the tensile test period. Low-alloy High-tensile Structural Steel. e 880 — oil 520 Water and oil 1080 885 8 229 980 835 10 229 26 e 880 — oil 230 Water and air 1620 — 9 229 35CrMnSiA 11 . c 880 oil 200 Water and air 980 785 10 187 835 540 10 179 7 20Crc. e 880 — Water and oil 500 Water and oil 885 685 11 197 845 635 12 197 17 35CrMo 850 — oil 550 Water and oil 980 835 12 229 18 42CrMo 850 — oil 560 Water and oil 1080 930 12 217 19 12CrMoV 970 — air 750 air 440 225 22 241 20 12CrlMoV 970 — air 750 air 490 245 22 179 21 38CrMoAIe 940 — Water and oil 640 Water and oil 980 835 12 229 930 785 14 229 22 50CrVA 860 — oil 500 Water and oil 1275 1130 10 255 23 20CrMn 850 — oil 200 Water and air 930 735 10 187 24 20CrMnSie 880 — oil 480 Water and oil 785 635 12 207 25 30CrMnSic. e 880 Water and oil 200 Water and air 785 490 10 179 800 8 30Cr 860 — oil 500 Water and oil 885 685 11 187 9 35Cr 860 — oil 500 Water and oil 930 735 11 207 10 40Cr 850 — oil 520 Water and oil 980 785 9 207 11 45Cr 840 — oil 520 Water and oil 1030 835 9 217 12 50Cr 830 — oil 520 Water and oil 1080 930 9 229 13 38CrSi 900 — oil 600 Water and oil 980 835 12 255 14 12CrMo 900 — air 650 air 410 265 24 179 15 15CrMo 900 — air 650 air 440 295 22 179 16 20CrMoc.Table 7 Mechanical Properties of Alloy Steel Tube Recommended heat treatment system a Brinell Hardness Tensile property of steel tube Quenching (normalizing) Serial number Grade Temperature /℃ For the For the Coolant Tensile Lower yield Post-breaking Tempering Temperature /℃ strength strength f extensibility Rm/MPa ReL/MPa A/% Coolant No less than first time second time 1 40Mn2 840 2 45Mn2 3 — annealing or high tempering in delivery state No greater than Water and oil 540 Water and oil 885 735 12 217 840 Water and oil 550 Water and oil 885 735 10 217 27SiMn 920 Water 450 Water and oil 980 835 12 217 4 40MnBb 850 oil 500 Water and oil 980 785 10 207 5 45MnB b 840 oil 500 Water and oil 1030 835 9 217 6 20Mn2Bb. and the normalizing temperature shall be no higher than its quenching temperature.4. 5.3. while the impact absorbed energy and test temperature of its compound ratio V-notch impact test shall be in accordance with those specified in Table 6.1 For low-alloy high-tensile structural steel and Q235 or Q275 steel tubes. the Brinell hardness shall be in accordance with those specified in Table 7. it may be delivered according to any group of data therein. f During the tensile test period. b The boracic steel may be normalizing before quenching.Table 7 (Continued) Recommended heat treatment system a Brinell Tensile property Hardness of Quenching (normalizing) Tempering Tensile strength Serial number Grade Temperature /℃ For the first time For the Rm/MPa Coolant Temperature /℃ Lower yield strength f Post-breaking steel tube extensibility annealing or A/% high tempering ReL/MPa in delivery state Coolant No less than second No greater than time 27 d e 20CrMnTi - 880 870 oil 200 Water and air 1080 835 10 217 28 30CrMnTid-e 880 850 oil 200 Water and air 1470 — 9 229 29 12CrNi2 860 780 Water and oil 200 Water and air 785 590 12 207 30 12CrNi3 860 780 oil 200 Water and air 930 685 11 217 31 12Cr2Ni4 860 780 oil 200 Water and air 1080 835 10 269 32 40CrNiMoA 850 — oil 600 Water and oil 980 835 12 269 45CrNiMoVA 860 — oil 460 oil 1470 1325 7 269 33 a The permissible adjustment range of heat treatment temperature listed in the table: ±20℃ for quenching. when the purchaser is not specified. ±50℃ for high-temperature tempering. when the undersized bearing impact sample is used. impact test shall be made. if yield strength cannot be measured. the specified non-proportion extension intensity RP0.3.4.2 Hardness test The alloy structure steel tube delivered in annealing or high-temperature tempering state and in wall thickness of no greater than 5mm.4.3 Impact test 5. the desired value of minimum Charpy V-notch impact absorbed energy shall be the product of desired value for the impact absorbed 12 .5 mm.2 Impact absorbed energy listed in Table 6 is the desired value of impact absorbed energy for Charpy V-notch samples in standard dimension. single value of one of the samples therein is permitted to be less than the specified value. 5. when their outside diameter is no less than 70mm and their wall thickness is no less than 6. ±30℃ for low-temperature tempering. 5. e Isothermal quenching at temperature of 280℃~ 320℃.2 may be measured to replace ReL. c Delivered according to a group of data specified by the purchaser. d The first quenching of Cr-Mn-Ti steel may be replaced by normalizing. When the steel tube dimension cannot prepare samples in standard dimension. but it shall be no less than 70% of the specified value.4. undersized bearing samples may be prepared. Impact absorbed energy is calculated according to arithmetic mean value of three samples of one group. the practical wall thickness at the removing part shall be no less than the minimum allow of the wall thickness deviation.energy of standard sized sample multiplied by reduction coefficient listed in Table 8. rolling and delamination. Q295. and indicated in the contract. As for other partial flaws.3 According to the requirements of the purchaser. steel tube with the outside diameter of no greater than 22mm may be made with bending test. Q345. The dimension of the impact sample shall give preference to select larger dimension. scar. after the bending.3.5 0.50 5. they are allowed to be present. with outside diameter of >22 mm~400mm and with wall thickness to outside diameter ratio of no greater than 10% shall be made with flattening test.5. These flaws shall be removed completely. with bend angle of 90°. 15. 20Mn. 25.5.5 Technical properties 5. foldover. Q295. 13 . and its test temperature.00 Small sample 10×7. Table 9 Flat Plate Interval after Steel Tube Flattening a Grade Flat plate interval of the flattening test (H)a/mm 10. crack or rupture is not allowed to emerge on the sample. Q345. 15. 20. 20Mn. and indicated in the contract.75 Small sample 10×5 0. testing size and impact absorbed energy are determined by the agreement of both the purchaser and the supplier. after flattening. through mutual negotiation of both the purchaser and the supplier. After flattening. and the removing depth shall not be more than the minus tolerance of the nominal wall thickness. 5.2 Bending test According to the requirements of the purchaser. Q235. Q275. 25Mn 7/8D The minimum value of flat plate interval (H) for the flattening test shall be 5×wall thickness of the steel tube. the sample sinuosity is not allowed to emerge crack or rupture.1 Flattening test The steel tube made of steels in grades of 10.4. steel with other grades and quality grades may also be made with Charpy V test. the flat plate interval of the steel tube shall be in accordance with those specified in Table 9. Q235 2/3D Q275. 25Mn. if their wall thickness is no less than the minus tolerance. through the mutual negotiation of both the purchaser and the supplier. 25.6 Surface quality Inside and outside surface of the steel tube are not allowed with visible crack. 5. 5. 20. Table 8 Reduction Coefficient of Impact Absorbed Energy for Undersized Bearing Sample Sample specifications Sample size (height×width) (mm×mm) Reduction coefficient Standard sample 10×10 1. and bend core radius of 6×outside diameter of the steel tube. sampling quantity. L4 (C12) for hot rolling (extruding and expanding steel tube). through mutual negotiation of both the purchaser and the supplier. with its acceptance grade is L4. and indicated in the contract. or with other methods.7 Nondestructive test According to the requirements of the purchaser. c) Magnetic leakage test is made according to requirements of GB/T 12606. b) Eddy current inspection is made according to requirements of GB/T 7735.1 4 Impact test GB/T 2975 GB/T 229 5 Flattening test GB/T 246 GB/T 246 6 Bending test GB/T 244 GB/T 244 7 8 9 Ultrasonic flaw detection test Eddy current test Magnetic flux leakage flaw detection test One sample from each of two pipes for each batch One sample from each of two pipes for each batch One group of 3 samples from each of two pipes for each batch One sample from each of two pipes for each batch One sample from each of two pipes for each batch Piece by piece Piece by piece Piece by piece GB/T 223 GB/T 4336 GB/T 20123 GB/T 20124 GB/T 20125 GB/T 228 ------- GB/T 5777 GB/T7735 GB/T 12606 14 . 6.1 The dimensions and contour of steel pipe shall be measured with the measuring tools in line with accuracy requirement.2 The internal and external surfaces of steel pipe shall be subject to visual inspection under sufficient lighting conditions. Table 10 Inspection item. 6. Test method 6. 6.3 The sampling method and test method for other inspection items of steel pipe shall meet the requirements as set in Table 10. with its acceptance grade is A. the steel tube may be nondestructive tested with one or more of the following methods.5. a) The artificial flaw dimension for making ultrasonic inspection according to GB/T 5777: L3 (C10) for cold drawing (rolling) pipe. Inspection item sampling quantity sampling method test method 1 Chemical composition One sample from each furnace GB/T 20066 2 Tensile test GB/T 2975 3 Hardness test GB/T 2975 GB/T 231. sampling method and test method No. furnace number and size. if less than 50% of the above provisions.3 Each batch shall be composed of the steel pipes of the same grade. 7. it shall constitute one batch separately. Inspection rules 7. 7.7.2 If the steel pipes are no longer heat treated after cut into single pieces. 15 . all the segments cut from the steel pipe rolled from one pipe ingot shall be deemed as one piece. b) Outer diameter greater than 351mm: 50 pieces.2.2. 8. if it is no less than 50% of the above provisions. 7. 25.2. 7. 7. c) Other dimensions: 200 pieces. 20.2. Q235.1 Examination and acceptance of steel pipe shall be conducted in terms of batch.1 Examination and acceptance The examination and acceptance of steel pipe shall be carried out by the quality and technical supervision department of the Supplier. marking and quality certification of steel pipes shall meet the requirement of GB/T 2102. 35.2 Rules for batch grouping 7.3 Sampling quantity The sampling quantity for each inspection item of each batch steel pipe shall meet the requirement of Table 10 hereof. The quantity of each batch of steel pipes shall not exceed the following provisions: a) Outer diameter no greater than 76mm and wall thickness no greater than 3 mm: 400 pieces. Q275. marking and quality certification The packaging. it can be integrated into the adjacent batch of the same grade.5 For the number of pieces of remaining steel pipes. Packaging. 20Mn and 25MN.4 Rules for reinspection and determination The reinspection and determination of steel pipes shall meet the requirement of GB/T 2102. one batch can be composed of the steel pipes of the same grade and the same size from different furnace numbers as for 10. the same size and the same treatment system (furnace). 45. 7.4 When special requirements are proposed by the Buyer in advance. 15.2. the same furnace number. 7. then.