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GB/T 21833.1-2020 English PDF (GBT21833.1-2020)

GB/T 21833.1-2020 English PDF (GBT21833.1-2020)

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GB/T 21833.1-2020: Seamless austenitic-ferritic (duplex) stainless steel tubes and pipes -- Part 1: Tubes for heat exchanger

This Part of GB/T 21833 specifies the order content, dimensions, shapes, masses, technical requirements, test methods, inspection rules, packing, marking, and quality certification of seamless austenitic-ferritic (duplex) stainless steel tubes and pipes for heat exchanger.
GB/T 21833.1-2020
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 77.140.75
H 48
Partially replacing GB/T 21833-2008
Seamless austenitic-ferritic (duplex) stainless steel
tubes and pipes - Part 1: Tubes for heat exchanger
ISSUED ON: APRIL 28, 2020
IMPLEMENTED ON: NOVEMBER 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Order content ... 7
4 Dimensions, shapes, and masses ... 8
5 Technical requirements ... 10
6 Test methods ... 16
7 Inspection rules ... 17
8 Packing, marking, and quality certification ... 18
Appendix A (Informative) High-temperature mechanical properties of some designations ... 19
Seamless austenitic-ferritic (duplex) stainless steel
tubes and pipes - Part 1: Tubes for heat exchanger
1 Scope
This Part of GB/T 21833 specifies the order content, dimensions, shapes, masses, technical requirements, test methods, inspection rules, packing, marking, and quality certification of seamless austenitic-ferritic (duplex) stainless steel tubes and pipes for heat exchanger.
This Part applies to seamless austenitic-ferritic (duplex) stainless steel tubes and pipes for heat exchanger (hereinafter referred to as steel tubes).
2 Normative references
The following documents are indispensable for the application of this document. For the dated references, only the editions with the dates indicated are applicable to this document. For the undated references, the latest edition (including all the amendments) are applicable to this document.
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 iodometric 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 223.26 Iron, steel and alloy - Determination of molybdenum content - The thiocyanate spectrophotometric method
GB/T 223.28 Methods for chemical analysis of iron, steel and alloy - The ??- benzoin oxime gravimetric method for the determination of molybdenum
content
GB/T 4340.1 Metallic materials - Vickers hardness test - Part 1: Test method GB/T 5777-2019 Automated full peripheral ultrasonic testing of seamless and welded (except submerged arc-welded) steel tubes for the detection of
longitudinal and/or transverse imperfections
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 13305 Micrographic method for determining area content of the ??-
phases in stainless steels
GB/T 17395 Dimensions, shapes, masses and tolerances of seamless steel
tubes
GB/T 17897 Corrosion of metals and alloys - Corrosion test for pitting
corrosion resistance of stainless steels in the ferric chloride solution 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) 3 Order content
The contract or order for ordering in accordance with this Part shall include the following:
a) Number of this Part;
b) Product name;
c) Steel designation;
d) Dimensions and specifications (outer diameter, wall thickness, and length); e) Quantity ordered (total mass or total length);
f) Delivery state;
4.2 Length
4.2.1 Normal length
The normal length of the steel tubes is 3000 mm~12000 mm. According to the requirements of the purchaser, through negotiation between the supplier and the purchaser, and indicated in the contract, steel tubes of other lengths can be supplied.
4.2.2 Fixed length and multiple length
According to the requirements of the purchaser, through negotiation between the supplier and the purchaser, and indicated in the contract, steel tubes with fixed length, multiple length, or other specific length requirements can be supplied. The total fixed length and multiple length shall be within the normal length range. The tolerance of the total length is mm. For steel tubes
delivered in multiple lengths, the cut margin shall be 5 mm~10 mm for each cut. 4.3 Bending
The bending of each meter of the steel tube shall not be greater than 1.5 mm/m. The bending of the total length shall not be greater than 0.1% of the length of the steel tube.
4.4 Out-of-roundness and uneven wall thickness
The out-of-roundness and uneven wall thickness of the steel tubes shall not exceed 80% of the tolerances of the outer diameter and wall thickness,
respectively.
4.5 End shape
The end faces of both ends of the steel tube shall be perpendicular to the axis of the steel tube. It shall remove the cut burrs.
4.6 Masses
Steel tubes are delivered according to actual mass; can also be delivered according to theoretical mass. The theoretical mass of the steel tube per meter is calculated according to formula (1). When delivered according to the minimum wall thickness, the theoretical mass of the steel tube is 1.1 times the value calculated according to formula (1).
Where:
5.2 Manufacturing method
5.2.1 Smelting method of steel
Steel shall be smelted by electric arc furnace plus external refining or converter plus external refining or electroslag remelting process. Through negotiation between the supplier and the purchaser, and indicated in the contract, other smelting methods can also be used.
5.2.2 Manufacturing method of steel tube
The steel tubes shall be manufactured by cold-drawing (rolling) seamless production process.
5.3 Delivery state
5.3.1 Steel tubes shall be delivered after heat treatment and pickling. Steel tubes, which have been heat-treated in a protective atmosphere or ground (polished) as a whole, can be delivered without pickling.
5.3.2 See Table 3 for the recommended heat treatment system for steel tubes. Through negotiation between the supplier and the purchaser, and indicated in the contract, heat treatment systems other than Table 3 can be used for steel tubes.
5.4 Mechanical properties
5.4.1 The longitudinal mechanical properties of steel tubes delivered in heat- treated state shall comply with the requirements of Table 3.
5.4.2 Steel tubes shall be tested for Vickers or Rockwell hardness. The values shall comply with the requirements of Table 3.
nominal wall thickness. The actual wall thickness at the removal location shall not be less than the allowable minimum wall thickness. Other local defects not exceeding the lower tolerance of wall thickness are allowed.
5.13 Special requirements
When the purchaser has the following special requirements, the supplier and the purchaser shall negotiate and indicate in the contract:
a) Adjust the chemical composition range specified in Table 3;
b) Provide modulus of elasticity and thermal expansion coefficient data; c) Carry out the test of harmful precipitating phase;
d) Provide the measured data of high-temperature mechanical properties. For high-temperature mechanical property values of some designations,
see Appendix A;
e) Specify the content of austenite or ferrite different from the requirements of 5.8;
f) Other requirements.
6 Test methods
6.1 Sampling for chemical composition analysis of steel tubes shall be carried out according to the rules of GB/T 20066. The chemical composition analysis is usually carried out according to GB/T 11170, GB/T 20123, GB/T 20124, or other general methods. During arbitration, it shall be carried out according to the provisions of GB/T 223.11, GB/T 223.18, GB/T 223.19, GB/T 223.25, GB/T
223.26, GB/T 223.28, GB/T 223.36, GB/T 223.43, GB/T 223.59, GB/T 223.60, GB/T 223.64, GB/T 223.85, and GB/T 223.86.
6.2 The dimensions and shapes of the steel tubes shall be measured one by one using a measuring tool, which meets the accuracy requirements.
6.3 The inner and outer surfaces of the steel tubes shall be visually inspected one by one under sufficient lighting conditions.
6.4 The sampling methods and test methods for other inspection items of steel tubes shall comply with the provisions of Table 5.

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