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This standard is drafted in accordance with the rules given in the GB/T 1.1-2009.
This standard replaces GB/T 24593-2009 Welded Austenitic Stainless Steel Tubes for Boiler and Heat-exchanger. The following technical deviations have been made with respect to the GB/T 24593-2009 (the previous edition):
— the requirements for length are modified (see 4.2; 4.2 in Edition 2009);
— the requirements for out-of-roundness are modified (see 4.4; 4.4 in Edition 2009);
— three steel designations 015Cr21Ni26Mo5Cu2, 015Cr20Ni18Mo6CuN and 022Cr21Ni25Mo7N are added (see 5.1.1 and 5.4).
— the requirements for P content in chemical components of various designations were modified (see 5.1.1; 5.1.2 in Edition 2009);
— underwater air tightness test is added in the pressure test options (see 5.6.2).
This standard was proposed by the China Iron and Steel Association.
This standard is under the jurisdiction of AC/TC 183 (National Technical Committee on Iron and Steel of Standardization Administration of China).
The previous editions of this part are as follows:
— GB/T 24593-2009.
Welded Austenitic Stainless Steel Tubes for Boiler and Heat Exchanger
1 Scope
This standard specifies order contents, dimension, appearance, weight and permissible deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of welded austenitic stainless steel tubes for boiler and heat exchanger.
This standard is applicable to the welded austenitic stainless steel tubes for heat exchangers and middle/low pressure boilers (hereinafter referred to as “steel tubes”).
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 Permissible Tolerances for Chemical Composition of Steel Products
GB/T 223.11 Iron, Steel and Alloy — Determination of Chromium Content — Visual Titration or Potentiometric Titration Method
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 223.19 Methods for Chemical Analysis of Iron, Steel and Alloy — The Neocuproine-chloroform Extraction Photometric Method for the Determination of Copper Content
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 223.28 Methods for Chemical Analysis of Iron, Steel and Alloy — The α-benzoinoxime Gravimetric Method for the Determination of Molybdenum Content
GB/T 223.36 Methods for Chemical Analysis of Iron, Steel and Alloy — the Neutral Titration Method for the Determinaion of Nitrogen Content after Distillation Separation
GB/T 223.37 Methods for Chemical Analysis of Iron, Steel and Alloy — The Indophenol Blue Photometric Methods for the Determination of Nitrogen Content after Distillation Separation
GB/T 223.40 Iron, Steel and Alloy — Determination of Niobium Content by the Sulphochlorophenol S Spectrophotometric Method
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 223.60 Methods for Chemical Analysis of Iron, Steel and Alloy — The Perchloric Acid Dehydration Gravimetric Method for the Determination of Silicon Content
GB/T 223.62 Methods for Chemical Analysis of Iron, Steel and Alloy — The Butyl Acetate Extraction Photometric Method for the Determination of Phosphorus Content
GB/T 223.84 Steel and Alloy — Determination of Titanium Content — Diantipyrylmethane Spectrophotometric Method
GB/T 223.85 Steel and Iron — Determination of Sulfur Content — Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 223.86 Iron, Steel and Alloy — Determination of Total Carbon Content — Infrared Absorption Method after Combustion in an Induction Furnace
GB/T 228.1 Metallic Materials — Tensile Testing — Part 1: Method of Test at Room Temperature
GB/T 230.1 Metallic Materials — Rockwell Hardness Test — Part 1: Test method (Scales A, B, C, D, E, F, G, H, K, N, T)
GB/T 241 Metallic Pipe — Hydraulic Pressure Test Method
GB/T 242 Metallic Materials — Tube — Drift Expanding Test
GB/T 245 Metallic Materials — Tube — Flanging Test
GB/T 246 Metallic Materials — Tube — Flattening Test
GB/T 2102 Acceptance, Packing, Marking and Quality Certification of Steel Pipe
GB/T 2653 Bend Test Methods on Welded Joints
GB/T 2975 Steel and Steel Products — Location and Preparation of Samples and Test Pieces for Mechanical Testing
GB/T 4334-2008 Corrosion of Metals and Alloys — Test Methods for Intergranular Corrosion of Stainless Steels
GB/T 4340.1 Metallic Materials — Vickers Hardness — Part 1: Test Method
GB/T 6394 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 11170 Stainless Steel — Determination of Multi-element Contents — Spark Discharge Atomic Emission Spectrometric Method (Routine Method)
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 (Routine Method)
GB/T 21835 Dimensions and Masses per Unit Length of Welded Steel Pipes
3 Order Contents
The contract or order for ordering steel tubes according to this standard shall include the following contents:
a) reference to this standard;
b) product name;
c) designation of steel
d) dimensions (outer diameter × wall thickness, in mm);
e) quantity;
f) special requirements.
4 Dimension, Appearance, Weight and Permissible Deviation
4.1 Outer diameter and wall thickness
4.1.1 The outer diameter (D) of the steel tubes shall not exceed 305 mm, and the wall thickness (S) shall not exceed 8.0 mm. The outer diameter and wall thickness shall comply with the requirements of GB/T 21835.
4.1.2 The tolerances for outer diameter of steel tubes shall be in accordance with those specified in Table 1.
4.1.3 Steel tubes of other diameters, wall thickness and/or allowable deviations may be supplied upon request by the purchaser through consultation between the supplier and the purchaser and as specified in the contract.
Table 1 Tolerances for Outer Diameter and Wall Thickness
Dimensions in millimeters
Outer diameter D Allowable deviation of Outer diameter Allowable deviation of wall thickness
For thin-wall steel tubes with a ratio of wall thickness to external diameter not greater than 3%, the measured average external diameter of the steel tubes shall comply with the allowable deviation of external diameter listed in this table.
4.2 Length
The normal length of steel tubes is 3,000mm to 12,000mm. Indicated in the contract upon the agreement of the supplier and the purchaser, other types of steel tubes may also be supplied.
As required by the purchaser, based on the agreement of both the supplier and the purchaser and the note indicated in the contract, the steel tubes may be delivered with specified length or multiple length. The allowable deviation of the length of the fixed-length steel tube is mm. Each multiple length steel tube shall set the incision margin of 5 mm to 10 mm.
4.3 Curvature
The bending of steel tubes shall not be greater than 1.5 mm/m.
4.4 Out-of-roundness
The out-of-roundness of steel tube shall not exceed the permissible variation of outer diameter; however, for the thin steel tube with a ratio of wall thickness to outer diameter not greater than 3%, the out-of-roundness shall not exceed 1.5% of nominal outer diameter.
4.5 End shape
The both end surfaces of steel tubes shall be vertical to the axis of steel tubes and shall be cleaned away with notch burr.
4.6 Resetting
Steel tubes are generally delivered by theoretical weight. As required by the purchaser and noted in the contract, the steel tubes may be delivered according to the theoretical weight. The theoretical weight per meter of steel tubes shall be calculated by using Formula (1):
Foreword II
1 Scope
2 Normative References
3 Order Contents
4 Dimension, Appearance, Weight and Permissible Deviation
5 Technical Requirements
6 Test Methods
7 Inspection Rules
8 Packaging, Marking and Quality Certificate
