标准编号:	GB/T 5310-2017/XG1-2019
中文名称:	高压锅炉用无缝钢管，含国家标准第1号修改单
英文名称:	Seamless steel tubes and pipes for high pressure boiler, includes Amendment 1
中标分类:	H48    钢管、铸铁管
行业分类:	GB    国家标准
ICS分类:	77.140.75 77.140.75    特殊用管钢 77.140.75
发布机构:	中华人民共和国国家质量监督检验检疫总局 中国国家标准化管理委员会
发布日期:	2017-12-29
实施日期:	2020-3-1
标准状态:	valid
替代旧标准:	GB/T 5310-2017 高压锅炉用无缝钢管
翻译语言:	英文
文件格式:	PDF
中文字符数:	25000 字
翻译价格(元):	1750.0
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This standard is developed in accordance with the rules given in GB/T 1.1-2009. This standard replaces GB/T 5310-2008 Seamless Steel Pipe for High Pressure Boiler, the following main technical changes have been made with respect to GB/T 5310-2008: ——The grade of steel is added; ——The smelting method of stainless steel is modified; ——Total elongation coefficient requirement is added; ——The heat treatment system of 15CrMoG steel pipe is modified; ——Hardness requirements are modified; ——Requirements for surface hardness are added; ——Requirements for flattening and bending tests are modified; ——The grain size requirement is modified; ——The microstructure requirements are modified; ——Depth requirements for decarburization layer are modified; ——Surface quality requirements are modified; ——Specified plastic elongation strength under high temperature of 10Cr9MoW2VNbBN and 07Cr25Ni21NbN are modified; ——Recommended data about endurance strength of 10Cr9MoW2VNbBN, 07Cr25Ni21NbN and 08Cr18Ni11NbFG are modified. This standard was proposed by China Iron and Steel Industry Association. This standard is under the jurisdiction of the National Technical Committee on Steel of Standardization Administration of China (SAC/ TC 183). The previous versions of the standards replaced by this standard are as follows: ——GB 5310-1985, GB 5310-1995 and GB/T 5310-2008 Contents 1 Scope 2 2 Normative References 2 3 Classification Code 5 4 Order 5 5 Dimension, Shape, Weight and Deviation 6 6 Technical Requirements 10 7 Sample 31 8 Inspection and Test Method 32 9 Inspection Rules 34 10 Packaging, Marking and Quality Certificate 35 Annex A (Normative) Specified Plastic Elongation Strength at High Temperature 36 Annex B (Informative) Recommended Data on 100,000h Endurance Strength / MPa 38 Amendment No. 1 for National Standard GB/T 5310-2017 Seamless steel tubes and pipes for high pressure boiler In the original standard: Concerning the mechanical properties of steel tubes in Table 7, clause 6.4.1, for steel tubes with designation of 15CrMoG in the row of No.7, the required Brinell hardness is 125HBW~170HBW and the required Vickers hardness is 125HV~170HV; and for steel tubes with designation of 07Cr25Ni21NbN in the row of No.21, the required Brinell hardness is 175HBW~256 HBW and the required Vickers hardness is 85HRB~100HRB. Modifications: Concerning the mechanical properties of steel tubes in Table 7, clause 6.4.1, for steel tubes with designation of 15CrMoG in the row of No.7, the required Brinell hardness is 125HBW~195HBW and the required Vickers hardness is 125HV~195HV; and for steel tubes with designation of 07Cr25Ni21NbN in the row of No.21, the required Brinell hardness is 150HBW~256 HBW and the required Vickers hardness is 80HRB~100HRB.   Seamless Steel Tubes and Pipes for High Pressure Boilers 1 Scope This standard specifies classification, code name, dimension, shape, weight, technical requirements, specimen, test methods, inspection rules as well as packaging, marking and quality certificate. This standard is applicable to seamless tubes for manufacturing high-pressure steam boiler or above and seamless tubes used as pipelines. 2 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 222 Allowable Deviation of Chemical Composition of Finished Products GB/T 223.5 Steel and Iron - Determination of Acid-Soluble Silicon and Total Silicon Content - Reduced Molybdosilicate Spectrophotometric Method GB/T 223.9 Iron Steel And Alloy - Determination of Aluminium Content - Chrom Azurol Sphotometric Method GH/T 223.11 Determination of Chromium Content in Steel and Alloys - Visual Titration or Potentiometric Titration GB/T 223.14 Methods for Chemical Analysis of Iron, Steel and Alloy - The N-Benzoy-N-Phenylhydroxylamine Extraction Photometric Method for the Determination of Vanadium Content GB/T 223.16 Methods for Chemical Analysis of Iron, Steel and Alloy The Chromotropic Acid Photometric Method for The Determination Of Titanium Content GB/T 223.18 Methods for Chemical Analysis of Iron, Steel and Alloy - The Sodium Thiosulfate Separation Iodimetric Method for the Determination of Copper Content GB/T 223.23 Iron Steel and Alloy - Determination of Nickel Content - The Dimethylglyoxime Spectrophotometric Method GB/T 223.25 Methods for Chemical Analysis of Iron, Steel and Alloy - The Dimethylglyoxime Gravimetric Method for the Determination of Nickel Content GB/T 223.26 Iron Steel and Alloy - Determination of Molybdenum Content - The Thiocyanate Spectrophotometric Method GB/T 223.29 Iron Steel And Alloy - Determination of Lead Content - Carrier Precipitation-Xylenol Orange Spectrophotometric Method GB/T 223.30 Methods for Chemical Analysis of Iron, Steel and Alloy - The Arsenazo III Spectrophotometric Method for the Determination of Zirconium Content after Separation by P-Bromomandelic Acid GB/T 223.31 Iron Steel and Alloy - Determination of Arsenic Content - Distillation-molybdenum Blue Spectrophotometric Method GB/T 223.36 Methods for Chemical Analysis of Iron, Steel and Alloy - The Neutral Titration Method for the Determination of Nitrogen Content After Distillation Separation GB/T 223.38 Methods for Chemical Analysis of Iron, Steel and Alloy - The Anion-Exchange Separation-Gravimetric Method for the Determination of Niobium Content GB/T 223.40 Iron Steel and Alloy - Detetmination of Niobium Content by the Sulphochlorophenol Spectrophotometric Method GB/T 223.43 Iron Steel and Alloy - Determination of Tungsten Content - Gravimetryc Method and Spectrophotometric Method GB/T 223.47 Methods for Chemical Analysis of Iron, Steel and Alloy - The Carrier Precipitation-Molybdenum Blue Potometric Method for the Determination of Antimony Content GB/T 223.50 Methods for Chemical Analysis of Iron, Steel and Alloy The phenylfuorone-CTMAB Direct Photometric Method for the Determination of Tin Content GB/T 223.58 Methods for Chemical Analysis of Iron, Steel and Alloy - the Sodium Arsenite-Sodium Nitrite Titrimetric Method for the Determination of Manganese Content GB/T 223.59 Iron Steel and Alloy - Determination of Phosphorus Content - Bismuth phosphomolybdate Blue Spectrophotometric Method and Antimony Phosphomolybdate Blue Spectrophotometric Method GB/T 223.67 Iron Steel and Alloy - Determination of Sulfur Content -Methylene Blue Spectrophotometric Method GB/T 223.69 Iron Steel and Alloy - Determination of Carbon Contents - Gas-volumetric Method after Combustion in the Pipe Furnace GB/T 223.78 Methods for Chemical Analysis of Iron, Steel and Alloy - Curcumin Spectrophotometric Method for the Determination of Boron content GB/T 223.80 Iron Steel and Alloy - Determination of Trace Bismuth and Arsenic Contents - Hydride Generation-atomic Fluorescence Spectrometric Method GB/T 224 Determination of Depth of Decarburization of Steels GB/T 226 Low-power Microstructure and Defect Etching Test of Steel GB/T 228.1 Metallic Materials - Tensile Testing - Part 1: Method of Test at Room Temperature GB/T 228.2 Metallic Materials - Tensile testing - Part 2: Method of Test at Elevated Temperature GB/T 229 Metallic Materials - Charpy Pendulum Impact Test Method GB/T 230.1 Metallic Materials - Rockwell Hardness Test - Part 1: Test Method (scales A, B, C, D, E, F, G, H, K, N and T) GB/T 231.1 Metallic Materials - Brinell Hardness Test - Part 1: Test Method GB/T 232 Metallic Materials - Bend Test GB/T 241 Metal Materials - Tube - Hydrostatic Pressure Test GB/T 242 Metal Materials - Tube - Drift-expending Test GB/T 246 Metal Materials - Tube - Flattening Test GB/T 1979 Standard Diagrams for Macrostructure and Defect of Structural Steels GB/T 2102 Acceptance Packing 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 4336 Carbon and Low-Alloy Steel - Determination of Multi-element Contents - Spark Discharge Atomic Emission Spectrometric Method (Routine Method) GB/T 4340.1 Metallic Materials - Vickers Hardness Test - Part 1:Test Method GB/T 5777-2008 Seamless Steel Pipe and Tubing Methods for Ultrasonic Testing GB/T 6394-2017 Determination of Estimating the Average Grain Size of Metal GB/T 7735-2016 Automated Eddy Current Testing of Seamless and Welded(except Submerged Arc-welded) Steel Tubes for Detection of Imperfections GB/T 10561-2005 Steel Determination of Content of Nonmetallic Inclusions Micrographic Method Using Standards Diagrams GB/T 11170 Stainless Steel - Determination of Multi-Element Contents - Spark Discharge Atomic Emission Spectrometric Method (Routine Method) GB/T 12606-2016 Automated Full Peripheral Flux Leakage Testing of Seamless and Welded(except Submerged Arc-Welded) Ferromagnetic Steel Tubes for the Detection of Longitudinal and/or Transverse Imperfections GB/T 1329S Inspection Methods of Microstructure for Metals GB/T 15822 Non-destructive Testing - Magnetic Particle Testing GB/T 17395 Dimensions Shapes Masses and Tolerances of Seamless Steel Tubes GB/T 20066 Steel and Iron - Sampling and Preparation of Samples for the Determination of Chemical Composition 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 20124 Steel and Iron - Determination of Nitrogen Content - Thermal conductimetric Method after Fusion in a Current of Inert Gas GB/T 31925-2015 Ultrasonic Test Methods of Heavy Wall Thickness Seamless Steel Pipes and Tubes NB/T 47013.5 Nondestructive Testing of Pressure-Bearing Equipment - Part 5: Penetrant Testing YB/T 4149 Continuously Cast Round Billet for Seamless Steel tube and pipe Rolling YB/T 5137 Classification and Designation of Round Tube Blank 3 for Hot Rolling and Forging Seamless Steel Tubes for High Pressure Application 3 Classification Code 3.1 Seamless steel pipe of this standard is divided into two classes according to the product manufacturing method; its class and code are as follows: a) Hot rolled (extruded, expanded) steel tubes, with code name of W-H ; b) Cold drawn (rolled) steel pipe., with code name of W-C. 3.2 For the purpose of this document, the following codes apply. D——the outside Diameter, (including the outside diameter in mm, unless otherwise stated) S——the wall thickness (including the nominal wall thickness and the average wall thickness in mm, unless otherwise stated) Smin——the minimum wall thickness d——the nominal inside diameter Dc——the calculated outside diameter (outside diameter value in millimeters calculated by the sum of nominal inside diameter and nominal wall thickness) Sc——the average wall thickness (the average of the maximum and minimum wall thicknesses, in millimeters, calculated by the minimum wall thickness and its allowable deviation) 4 Order Contracts or orders for steel pipes ordered in accordance with this standard shall include, but not be limited to the followings: a) Product name; b) Standard number; c) Grade of steel; d) Quantity ordered (total weight or total length); e) Dimension and specification; f) Special requirements 5 Dimension, Shape, Weight and Deviation 5.1 Outside diameter and wall thickness 5.1.1 Unless otherwise specified in the contract, the steel tubes are delivered by outside diameter and wall thickness. Upon request by the purchaser and after negotiation between the purchaser and the supplier, the steel tubes may be delivered by nominal outside diameter and minimum wall thickness, nominal inside diameter and nominal wall thickness or other dimensions and specifications. 5.1.2 Outside diameter and wall thickness of steel tubes shall be in accordance with those specified in GB/T 17395. Upon the request by the purchaser and after negotiation between the purchaser and the supplier, the steel tubes with dimensions beyond those specified in GB/T 17395 can be supplied. If delivered by nominal inside diameter and nominal wall thickness, the dimension and specification shall be agreed by both sides. 5.1.3 If delivered by nominal outside diameter and nominal wall thickness, the permissible deviations shall be in accordance with those specified in Table 1. 5.1.4 If delivered by nominal outside diameter and minimum wall thickness, the permissible deviations of outside diameter shall be in accordance with those specified in Table 1, and the permissible deviations of wall thickness shall be in accordance with those specified in Table 2. 5.1.5 If delivered by nominal inside diameter and nominal wall thickness, the permissible deviations of nominal inside diameter shall be ±1%d, and that of nominal wall thickness shall be in accordance with those specified in Table 1. 5.1.6 If the purchaser doesn’t indicate the permissible deviations of steel tubes in the contract, the permissible deviations of outside diameter and wall thickness shall meet the requirements for normal grades. Upon request by the purchaser, after the negotiation between the purchaser and the supplier and in accordance with those stated in the contract, the steel tubes with permissible deviations of dimensions other than those specified in Table 1 and Table 2 can be supplied.

1 Scope 2 Normative References 3 Classification Code 4 Order 5 Dimension, Shape, Weight and Deviation 6 Technical Requirements 7 Sample 8 Inspection and Test Method 9 Inspection Rules 10 Packaging, Marking and Quality Certificate Annex A (Normative) Specified Plastic Elongation Strength at High Temperature Annex B (Informative) Recommended Data on 100,000h Endurance Strength / MPa

高压锅炉用无缝钢管 1范围 本标准规定了高压锅炉用无缝钢管的分类、代号、尺寸、外形、重量、技术要求、试样、试验方法、检验 规则、包装、标志和质量证明书。 本标准适用于制造高压及其以上压力的蒸汽锅炉、管道用无缝钢管。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文本。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本文件。 GB/T 222钢的成品化学成分允许偏差 GB/T 223.5钢铁 酸溶硅和全硅含量的测定 还原型硅钼酸盐分光光度法 GB/T 223.9钢铁及合金 铝含量的测定 铬天青S分光光度法 GH/T 223.11钢铁及合金 铬含量的测定 可视滴定或电位滴定法 GB/T 223.14钢铁及合金化学分析方法 钽试剂萃取光度法测定钒含量 GB/T 223.16钢铁及合金化学分析方法 变色酸光度法测定钛量 GB/T 223.18钢铁及合金化学分析方法 硫代硫酸钠分离-碘量法测定铜量 GB/T 223.23钢铁及合金镍含量的测定 丁二酮肟分光光度法 GB/T 223.25钢铁及合金化学分析方法 丁二酮肟重量法测定镍量 GB/T 223.26钢铁及合金 钼含量的测定 硫氰酸盐分光光度法 GB/T 223.29钢铁及合金 铅含量的测定 载体沉淀-二甲酚橙分光光度法 GB/T 223.30钢铁及合金化学分析方法 对-溴苦杏仁酸沉淀分离-偶氮胂Ⅲ分光光度法测定锆量 GB/T 223.31钢铁及合金 砷含量的测定 蒸馏分离-钼蓝分光光度法 GB/T 223.36钢铁及合金化学分析方法 蒸馏分离-中和滴定法测定氮量 GB/T 223.38钢铁及合金化学分析方法 离子交换分离-重量法测定铌量 GB/T 223.40钢铁及合金 铌含量的测定 氯磺酚S分光光度法 GB/T 223.43钢铁及合金 钨含量的测定 重量法和分光光度法 GB/T 223.47钢铁及合金化学分析方法 载体沉淀-钼蓝光度法测定锑量 GB/T 223.50钢铁及合金化学分析方法 苯基荧光酮-溴化十六烷基三甲基胺直接光度法测定锡量 GB/T 223.58钢铁及合金化学分析方法 亚砷酸钠-亚硝酸钠滴定法测定锰量 GB/T 223.59钢铁及合金 磷含量的测定 铋磷钼蓝分光光度法和锑磷钼蓝分光光度法 GB/T 223.67钢铁及合金 硫含量的测定 次甲基蓝分光光度法 GB/T 223.69钢铁及合金 碳含量的测定 管式炉内燃烧后气体容量法 GB/T 223.78钢铁及合金化学分析方法 姜黄素直接光度法测定硼含量 GB/T 223.80钢铁及合金 铋和砷含量的测定 氢化物发生-原子荧光光谱法 GB/T 224钢的脱碳层深度测定法 GB/T 226钢的低倍组织及缺陷酸蚀检验法   GB/T 228.1金属材料 拉伸试验 第1部分:室温试验方法 GB/T 228.2金属材料 拉伸试验 第2部分:高温试验方法 GB/T 229金属材料 夏比摆锤冲击试验方法 GB/T 230.1金属材料 洛氏硬度试验 第1部分:试验方法(A、B、C、D、E、F、G、H、K、N、T标尺) GB/T 231.1金属材料 布氏硬度试验 第1部分:试验方法 GB/T 232金属材料 弯曲试验方法 GB/T 241金属管 液压试验方法 GB/T 242金属管 扩口试验方法 GB/T 246金属管 压扁试验方法 GB/T 1979结构钢低倍织织缺陷评级图 GB/T 2102钢管的验收、包装、标志和质量证明书 GB/T 2975钢及钢产品 力学性能试验取样位置及试样制备 GB/T 4336碳素钢和中低合金钢 多元索含量的测定 火花放电原子发射光谱法（常规法） GB/T 4340.1金属材料 维氏硬度试验 第1部分：试验方法 GB/T 5777—2008无缝钢管超声波探伤检验方法 GB/T 6394—2017金属平均晶粒度测定方法 GB/T 7735—2016无缝和焊接(埋弧焊除外)钢管缺欠的自动涡流检测 GB/T 10561—2005钢中非金属夹杂物含量的测定 标准评级图显微检验法 GB/T 11170不锈钢 多元素含量的测定 火花放电原子发射光谱法（常规法） GB/T 12606—2016无缝和焊接（埋弧焊除外）铁磁性钢管纵向和/或横向缺欠的全圆周自动漏磁 检测 GB/T 1329S金属显微组织检验方法 GB/T 15822(所有部分） 无损检测 磁粉检测 GB/T 17395无缝钢管尺寸、外形、重量及允许偏差 GB/T 20066钢和铁 化学成分测定用试样的取样和制样方法 GB/T 20123钢铁 总碳硫含量的测定 高频感应炉燃烧后红外吸收法（常规方法） GB/T 20124钢铁 氮含量的测定 惰性气体熔融热导法（常规方法） GB/T 31925—2015厚壁无缝钢管超声波检验方法 NB/T 47013.5 承压设备无损检测 第5部分:渗透检测 YB/T 4149 连铸圆管坯 YB/T 5137高压用热轧和锻制无缝钢管圆管坯 3分类和代号 3.1本标准的无缝钢管按产品制造方式分为两类，其类別和代号如下： a) 热轧(挤压、扩）钢管，代号为W-H ； b) 冷拔（轧)钢管，代号为 3.2下列代号适用于本文件。 D 外径（如无特殊说明，包括公称外径和/或计算外径，单位为毫米） S 壁厚（如无特殊说明，包括公称壁厚和/或平均壁厚，单位为毫米） Smin 最小壁厚 d 公称内径 Dc 计算外径(按公称内径与公称壁厚之和计算出来的外径值，单位为毫米） Sc 平均壁厚(按最小壁厚及其允许偏差计算的壁厚最大值与最小值的平均值，单位为毫米）   4订货内容 按本标准订购钢管的合同或订单应包括但不限于下列内容： a) 产品名称； b) 标准编号； c) 钢的牌号； d) 订购的数量（总重量或总长度）； e) 尺寸规格； f) 特殊要求。 5尺寸、外形、重量及允许偏差 5.1外径和壁厚 5.1.1除非合同中另有规定，钢管按公称外径和公称壁厚交货。根据需方要求，经供需双方协商，钢管可按公称外径和最小壁厚、公称内径和公称壁厚或其他尺寸规格方式交货。 5.1.2钢管的公称外径和壁厚应符合GB/T 17395的规定。根据需方要求，经供需双方协商，可供应GB/T 17395规定以外尺寸的钢管。当钢管按公称内径和公称壁厚交货时，其尺寸规格由供需双方协 商确定。 5.1.3钢管按公称外径和公称壁厚交货时，公称外径和公称壁厚的允许偏差应符合表1的规定。 5.1.4钢管按公称外径和最小壁厚交货时，公称外径的允许偏差应符合表1的规定，壁厚的允许偏差应符合表2的规定。 5.1.5钢管按公称内径和公称壁厚交货时，其公称内径的允许偏差为±1%d，公称壁厚的允许偏差应 符合表1的规定。 5.1.6当需方未在合同中注明钢管尺寸允许偏差级別时，钢管外径和壁厚的允许偏差应符合普通级的规定。根据需方要求，经供需双方协商，并在合同中注明，可供应表1和表2规定以外尺寸允许偏差的钢管，或其他内径允许偏差的钢管 表1钢管公称外径和公称壁厚允许偏差 单位为毫米 分类代号 制造方式 钢管尺寸 允许偏差 普通级 高级 W-H 热轧（挤压） 钢管 公称外径 （D) <57 ±0.40 ±0.30 57～325 S≤35 ±0.75%D ±0.5%D S>35 ±1%D ±0.75%D >325～600 +1%D或+5，取较小者-2 — >600 +1%D或+7，取较小者-2 — 公称壁厚 (S) ≤4.0 ±0.45 ±0.35 >4.0～20 +12.5%S -10%S ±10%S >20 D<219 ±10%S ±7.5%S D≥219 +12.5%S -10%S ±10%S   表1（续） 单位为毫米 分类代号 制造方式 钢管尺寸 允许偏差 普通级 高级 W-H 热扩钢管 公称外径 （D) 全部 ±1%D ±0.75%D 公称壁厚 (S) 全部 +20%S -10%S +15%S -10%S W-C 冷拔（轧） 钢管 公称外径 (D) ≤25.4 ±0.15 — >25.4～40 ±0.20 — >40～50 ±0.25 — >50～60 ±0.30 — >60 ±0.5% D — 公称壁厚 (S) ≤3.0 ±0.3 ±0.2 >3.0 ±10%S ±7.5%S 表2 钢管最小壁厚的允许偏差 单位为毫米 分类代号 制造方式 壁厚范围 允许偏差 普通级 高级 W-H 热轧（挤压）钢管 Smin≤4.0 +0.9 0 +0.7 0 Smin>4.0 +25%Smin 0 +22%Smin 0 W-C 冷拔（轧）钢管 Smin≤3.0 +0.6 0 +0.4 0 Smin>3.0 +20%Smin 0 +15%Smin 0 5.2长度 5.2.1通常长度 5.2.1.1钢管的通常长度为4000 mm～12000mm。 5.2.1.2经供需双方协商，并在合同中注明，可交付长度大于12000 mm或短于4 000 mm但不短于3000 mm的钢管；长度短于4000 mm但不短于3000 mm的钢管，其数量应不超过该批钢管交货总数量的5 % 5.2.2定尺长度和倍尺长度 根据需方要求，经供需双方协商，并在合同中注明，钢管可按定尺长度或倍尺长度交货。钢管的定尺长度允许偏差为 。每个倍尺长度应按下述规定留出切口余量： a) D≤159 mm 时，切口余量为5 mm～10mm；   b)D>159 mm时，切口余量为10 mm～15 mm。 5.3弯曲度 5.3.1钢管的每米弯曲度应符合如下规定： a)S≤15mm时、不大于 1.5 mm/m； b)15 mm30 mm 时，不大于 3.0 mm/m。 5.3.2D≥127 mm的钢管，其全长弯曲度应不大于钢管长度的0.10%。 5.3.3根据需方要求，经供需双方协商，并在合同中注明，钢管的每米弯曲度和全长弯曲度可采用其他规定。 5.4不圆度和壁厚不均 根据需方要求，经供需双方协商，并在合同中注明，钢管的不圆度和壁厚不均应分別不超过外径和壁厚公差的80%。 5.5端头外形 钢管两端端面应与钢管轴线垂直，切口毛刺应予清除。 5.6 重量 5.6.1交货重量 5.6.1.1钢管按公称外径和公称壁厚或公称内径和公称壁厚交货时，钢管按实际重量交货，亦可按理论 重量交货。 5.6.1.2钢管按公称外径和最小壁厚交货时，钢管按实际重量交货；供需双方协商，并在合同中注明，钢 管亦可按理论重量交货。 5.6.2理论重量的计算 钢管理论重量的计算按GB/T 17395的规定（钢的密度按7.85 kg/dm3)，不锈（耐热）钢钢管的理论 重量为按GB/T 17395规定计算理论重量的1.015倍。 按最小壁厚交货钢管，应釆用平均壁厚计算理论重量；按公称内径交货钢管，应釆用计算外径计算 理论重量。 5.6.3重量允许偏差 根据需方要求，经供需双方协商，并在合同中注明，交货钢管实际重量与理论重量的偏差应符合如 下规定： a)单根钢管：±10%； b)每批最小为10t的钢管：±7.5%。 6技术要求 6.1钢的牌号和化学成分 6.1.1 钢的牌号和化学成分(熔炼成分)应符合表3的规定。 6.1.2钢中残余元素的含量应符合表4的规定。   6.1.3成品钢管的化学成分允许偏差应符合表5的规定。成品化学成分的相关术语、定义和判定方法应符合GB/T 222的规定 6.2 制造方法 6.2.1钢的冶炼方法 6.2.1.1优质碳素结构钢和合金结构钢应釆用电弧炉加炉外精炼并经真空精炼处理，或氧气转炉加炉 外精炼并经真空精炼处理.或电渣重熔法冶炼。 6.2.1.2不锈(耐热）钢应采用电弧炉加炉外精炼.或转炉加炉外精炼，或电渣重熔法冶炼。 6.2.1.3经供需双方协商，并在合同中注明，可采用其他较高要求的冶炼方法。需方指定某一种冶炼方法时，应在合同中注明。 6.2.2管坯的制造方法及要求 6.2.2.1管坯可采用连铸、模铸或热轧(锻)方法制造。 6.2.2.2连铸管坯应符合YB/T 4149的规定，其中低倍组织缺陷中心裂纹、中间裂纹、皮下裂纹和皮下气泡的级别应分别不大于1级，也可釆用经相关各方认可的其他更高质量要求；热轧（锻)管坯应符合 YB/T 5137的规定；模铸管坯（钢锭）可参照热轧(锻）管坯的规定执行。 6.2.3钢管的制造方法 6.2.2.3.1牌号为08Cr18Ni11NbFG的钢管应采用冷拔（轧）无缝方法制造，其他钢管应采用热轧（挤压、 扩)或冷拔（轧）无缝方法制造。 6.2.3.2热扩钢管应是坯料钢管经整体加热后扩制变形而成的更大口径的钢管。 6.2.3.3采用连铸或模铸钢坯直接轧制的钢管，其加工变形总延伸系数应不小于3。釆用电渣锭直接轧制的钢管，其加工变形总延伸系数应不小于2。