GB/T 40297-2021 English PDF (GB/T40297-2021)

GB/T 40297-2021: Seamless austenitic stainless steel pipes for high pressure hydrogenation unit
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GB/T 40297-2021
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.75
CCS H 48
Seamless austenitic stainless steel pipes for high pressure
hydrogenation unit
ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: MARCH 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Terms and definitions... 6 
4 Classification and code ... 7 
5 Order content ... 7 
6 Size, shape and weight ... 7 
7 Technical requirements ... 10 
8 Test methods ... 18 
9 Inspection rules ... 20 
10 Packaging, marking and quality certificate ... 20 
Seamless austenitic stainless steel pipes for high pressure
hydrogenation unit
1 Scope
This document specifies the classification and code, order content, size, shape and
weight, technical requirements, test methods, inspection rules, packaging, marking and
quality certificate of seamless austenitic stainless steel pipes for high pressure
hydrogenation unit.
This document applies to seamless austenitic stainless steel pipes for high pressure
hydrogenation units (hereinafter referred to as “steel pipes”); it also applies as a
reference for seamless austenitic stainless steel pipes for other hydrogen condition
devices.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this
document and are indispensable for its application. For dated references, only the
version corresponding to that date is applicable to this document; for undated references,
the latest version (including all amendments) is 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 223.25, 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 223.37, Iron, steel and alloy - Determination of nitrogen content - Indophenol
blue spectrophotometric method after distillation separation
GB/T 223.40, Iron, steel and alloy - Determination of niobium content by the
sulphochlorophenol S spectrophotometric method
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 223.60, Methods for chemical analysis of iron, steel and alloy - The perchloric
acid dehydration gravimetric method for the determination of silicon content
GB/T 223.63, Methods for chemical analysis of iron, steel and alloy - The sodium
(potassium) periodate photometric method for the determination of manganese
content
GB/T 223.82, Steel and iron - Determination of hydrogen content - Thermal
conductivity/infrared method after fusion under inert gas
GB/T 223.84, Steel and iron - 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, Steel and iron - 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 228.2, Metallic materials. Tensile testing. Part 2: Method of test at elevated
temperature
GB/T 230.1, Metallic materials - Rockwell hardness test - Part 1: Test method
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, Metallic materials - Tube - Flattening test
GB/T 1031, Geometrical product specifications (GPS) - Surface texture: Profile
method - Surface roughness parameters and their values
GB/T 2102, Acceptance, packing, marking and quality certification of steel pipe
GB/T 2975, Steel and steel products - Location and preparation of samples and test
pieces for mechanical testing
GB/T 4334-2020, Corrosion of metals and alloys - Test methods for intergranular
corrosion of austenitic and ferritic-austenitic (duplex) stainless steels
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 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 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 11261, Steel and iron - Determination of oxygen content - The pulse heating
inert gas fusion-infra-red absorption method
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 20490, Seamless and welded (except submerged arc-welded) steel tubes for
pressure purposes - Ultrasonic testing for the detection of laminar imperfections
GB/T 30062, Terminology of steel pipes and tubes
NB/T 47013.5-2015, Nondestructive testing of pressure equipment - Part 5:
Penetrant testing
YB/T 4307, Iron, Steel and Alloy - Determination of Oxygen, Nitrogen and
Hydrogen Contents - TOF-mass Spectroscopy Method after Fusion in a Current of
Inert Gas
YB/T 5137, Hot rolled and wrought round blank for high-pressure seamless steel
tube
3 Terms and definitions
Terms and definitions determined by GB/T 30062 are applicable to this document.
The end faces of both ends of the steel pipe shall be perpendicular to the axis of the
steel pipe; the cut burrs shall be removed. As required by the buyer, negotiated between
the supplier and the buyer, and indicated in the contract, the two ends of the steel pipe
can be processed with grooves, and the groove type shall be determined through
negotiation between the supplier and the buyer.
6.5 Out-of-roundness and unevenness in wall thickness
The out-of-roundness and unevenness in wall thickness of the steel pipe shall not
exceed 80% of the outside diameter allowance and the wall thickness allowance,
respectively.
6.6 Weight
6.6.1 Steel pipes shall be delivered by actual weight. After it is negotiated between the
supplier and the buyer, and indicated in the contract, the steel pipes can also be delivered
according to the theoretical weight. The theoretical weight of the steel pipe per meter is
calculated according to Formula (1):
Where:
W – theoretical weight of the steel pipe, in kilograms per meter (kg/m);
π – pi, which shall be 3.141 6;
ρ – density of steel, in kilograms per cubic decimeter (kg/dm3), as shown in Table 4;
S – wall thickness of the steel pipe, in millimeters (mm);
D – nominal outside diameter of the steel pipe, in millimeters (mm).
6.6.2 For steel pipes delivered according to the nominal outside diameter and minimum
wall thickness, the theoretical weight shall be calculated by the average wall thickness.
The average wall thickness is the average value of the maximum and minimum wall
thicknesses calculated according to the wall thickness and its permissible deviation.
6.6.3 When the steel pipes are delivered according to the theoretical weight, the supplier
and the buyer can negotiate the weight permissible deviation and indicate it in the
contract.
7 Technical requirements
7.1 Steel designation and chemical composition
The tube blank shall be manufactured by hot rolling (forging) method, and shall comply
with the provisions of YB/T 5137; the total elongation coefficient of processing
deformation shall not be less than 3.
Note: The total elongation coefficient of processing deformation is usually expressed
by the cross-sectional area ratio, length ratio or height ratio before and after
deformation.
7.2.3 Manufacturing method of steel pipes
Steel pipes shall be manufactured by cold rolling (drawing) or hot rolling (extruding,
upsetting, forging). Where the buyer specifies a certain manufacturing method, it shall
be indicated in the contract.
7.3 Delivery state
7.3.1 Steel pipes shall be delivered after heat treatment and pickling. All steel pipes that
have been wholly ground, bored or heat-treated in protective atmosphere can be
delivered without pickling. See Table 4 for the recommended heat treatment system for
steel pipes.
7.3.2 06Cr18Ni11Ti, 07Cr19Ni11Ti, 06Cr18Ni11Nb and 07Cr18Ni11Nb steel pipes
shall be subjected to stabilization heat treatment after solution heat treatment. The
stabilization heat treatment system shall be determined through negotiation between the
supplier and the buyer.
7.3.3 For hot-rolled (extruded, upset, forged) steel pipes, if direct water cooling or other
rapid cooling is carried out within the heat treatment temperature range specified in
Table 4 after hot deformation, it shall be deemed that the steel pipe solution heat
treatment requirements have been met.
7.3.4 After it is negotiated between the supplier and the buyer, and indicated in the
contract, other heat treatment systems other than those specified in Table 4 can be
adopted for the steel pipe.
7.4.1 Mechanical properties
7.4.1 Room temperature mechanical properties
The room temperature mechanical properties of the steel pipes in the delivery state shall
comply with the requirements in Table 4.
Where:
p – test pressure, in megapascals (MPa), which shall be rounded off to the nearest 0.5
MPa when p< 7 MPa, and to the nearest 1 MPa when p≥7 MPa;
S – wall thickness of the steel pipe, in millimeters (mm);
R – allowable stress, which shall be 60% of the minimum plastic elongation strength
specified in Table 4, in megapascals (MPa);
D – nominal outside diameter of the steel pipe, in millimeters (mm).
7.5.2 The chloride ion (Cl-) content (mass fraction) in the water used for the hydraulic
test shall not exceed 25×10-6.
7.5.3 With the consent of the buyer, the supplier may use eddy current testing instead
of the hydraulic test. In eddy current testing, the acceptance grade shall meet the
requirements of E4H or E4 in GB/T 7735-2016.
7.6 Process performance
7.6.1 Flattening
7.6.1.1 The steel pipes shall be subjected to a flattening test. Flattening shall be
performed in the following two steps.
a) The first step is the ductility test. The sample shall be pressed to H, the distance
between the two plates, and shall not have cracks or breaches. H shall be
calculated according to Formula (3).
Where:
H – the distance between the two plates, in millimeters (mm);
α – deformation coefficient per unit length, which shall be 0.09;
S – wall thickness of the steel pipe, in millimeters (mm);
D – nominal outside diameter of the steel pipe, in millimeters (mm).
b) The second step is the integrity test (closed flattening). The flattening shall be
continued until the sample ruptures or the sample collides with opposite walls;
the sample shall not show any visible separation, white spots or inclusions during
the entire flattening test.
7.6.1.2 The following conditions shall not be used as the basis for judging whether the
flattening test is qualified or not:
a) cracks or breaches caused by defects on the inner surface of the sample;
b) cracks or breaches on the inner surface of the sample at the 6 o’clock (bottom)
and 12 o’clock (top) positions, when S/D >0.1.
7.6.2 Bending test
7.6.2.1 For steel pipes with an outside diameter greater than 600 mm or a ratio of wall
thickness to outside diameter greater than 15%, a bending test may be adopted instead
of a flattening test. A set of bending tests shall include a forward bending (the surface
of the sample near the outer surface of the steel pipe is deformed in tension) and a
reverse bending (the sample near the inner surface of the steel pipe is deformed in
tension).
7.6.2.2 The diameter of the bending core of the bending test is 25 mm; the sample shall
be bent 180° at room temperature. After bending, there shall be no visible cracks or
breaches on the tensile surface and sides of the sample.
7.6.2.3 The sample for the bending test shall be taken along the transverse direction of
the steel pipe; the sample preparation shall comply with the provisions of GB/T 232.
When the sample is taken, the forward bending sample shall be as close as possible to
the outer surface, and the reverse bending sample shall be as close as possible to the
inner surface. There shall be no obvious scars or other defects on the surface of the
sample under bending and tension deformation. The sectional dimensions of the sample
after processing shall be 12.5 mm × 12.5 mm or 25 mm × 12.5 mm (width × thickness);
the four corners on the section shall be rounded, the radius of the rounded corners shall
not be greater than 1.6 mm, and the length of the sample shall not be greater than 150
mm.
7.6.3 Flaring
Steel pipes whose outside diameter is not more than 150 mm and wall thickness is not
more than 10 mm shall be subjected to a flaring test. The taper of the top core of the
flarin...