GB/T 37792-2019 PDF in English
GB/T 37792-2019 (GB/T37792-2019, GBT 37792-2019, GBT37792-2019)
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General specification for welded corrosion resistant alloy pipes and tubes
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GB/T 37792-2019: PDF in English (GBT 37792-2019) GB/T 37792-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.99; 77.140.75
H 59
General specification for welded corrosion resistant
alloy pipes and tubes
ISSUED ON: AUGUST 30, 2019
IMPLEMENTED ON: JULY 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 5
2 Normative references ... 5
3 Dimensions, shape, weight ... 6
4 Technical requirements ... 9
5 Test methods ... 13
6 Inspection rules ... 14
7 Packing, marking, and quality certification ... 15
General specification for welded corrosion resistant
alloy pipes and tubes
1 Scope
This Standard specifies the dimensions, shape, weight, technical requirements,
test methods, inspection rules, packing, marking, and quality certification
document of welded corrosion resistant alloy pipes and tubes.
This Standard applies to general requirements of welded corrosion resistant
alloy pipes and 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 223 (all parts) Methods for chemical analysis of iron, steel and alloy
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
GB/T 231.1 Metallic materials - Brinell hardness test - Part 1: Test method
GB/T 241 Metal materials - Tube - Hydrostatic pressure test
GB/T 242 Metal materials - Tube - Drift-expanding test
GB/T 246 Metal materials - Tube - Flattening test
GB/T 2102 Acceptance, packing, marking and quality certification of steel
pipe
GB/T 2651 Tensile test method on welded joints
GB/T 2653 Bend test methods on welded joints
GB/T 2975 Steel and Steel Products - Location and Preparation of Test
Pieces for Mechanical Testing
GB/T 4340.1 Metallic materials - Vickers hardness test - Part 1: Test method
GB/T 6394 Determination of estimating the average grain size of metal
GB/T 7735 Automated eddy current testing of seamless and welded (except
submerged arc-welded) steel tubes for detection of imperfections
GB/T 8647 (all parts) The methods for chemical analysis of nickel
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 15007 Designations of corrosion-resistant alloy
GB/T 15260 Corrosion of metals and alloys - Test methods for intergranular
corrosion of nickel alloys
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 20125 Low-alloy steel - Determination of multi-element contents -
Inductively coupled plasma atomic emission spectrometric method
GB/T 21835 Dimensions and masses per unit length of welded steel pipes
NB/T 47013.2-2015 Nondestructive testing of pressure equipment - Part 2:
Radiographic testing
NB/T 47013.5-2015 Nondestructive testing of pressure equipment - Part 5:
Penetrant testing
NB/T 47013.11-2015 Nondestructive testing of pressure equipment - Part 11:
Standard practice for X-ray digital radiography
3 Dimensions, shape, weight
3.1 Outer diameter and wall thickness
3.1.1 The nominal outer diameter (D) and nominal wall thickness (S) of the
welded pipes and tubes shall comply with the provisions of GB/T 21835.
D - The nominal outer diameter of the welded pipe and tube, in millimeters (mm).
4 Technical requirements
4.1 Designation and chemical composition
4.1.1 The designation and chemical composition of the corrosion resistant alloy
shall comply with the requirements of the corresponding product standard.
4.1.2 The permissible tolerances for chemical composition of welded pipe and
tube products shall comply with the provisions of GB/T 15007.
4.2 Manufacture
4.2.1 Smelting method
The alloy shall be smelted by means of electric arc furnace plus external refining
plus electroslag remelting, or other smelting methods which meet the
requirements of this Standard. The smelting method shall be indicated in the
quality certification.
4.2.2 Manufacturing method of welded pipes and tubes
4.2.2.1 The welded pipes and tubes shall be manufactured by single-sided or
double-sided automatic welding method without adding or adding filler metal.
4.2.2.2 When filler metal is added during the manufacturing process of the
welded pipes and tubes, a matching filler metal shall be selected, or a filler
metal with a higher alloy content may be selected.
4.2.2.3 Through negotiation between the supplier and the purchaser, and
indicated in the contract, welded pipes and tubes with a nominal outer diameter
of not less than 508 mm allow for double longitudinal welds or circumferential
weld joints of the same quality as longitudinal welds.
4.2.2.4 Two-time repair welding is not allowed at the same position of the weld
of the welded pipes and tubes. The defect of the base metal does not allow for
repair welding.
4.2.3 Delivery state
The welded pipes and tubes shall be delivered in a heat-treated plus pickled
state. The recommended heat treatment system shall be specified in the
corresponding product standard or contract. Welded pipes and tubes which are
overall polished, buffed, or heat treated in protective atmosphere may be not
subjected to pickling. If delivered in other states, it shall be determined by
D - The nominal outer diameter of the welded pipe and tube, in millimeters (mm).
4.4.2 Drift-expanding
The drift-expanding test has a center taper of 60°. The drift-expanding rate of
outer diameter is not less than 15%. After drift-expanding, the sample shall not
have cracks or gaps.
4.4.3 Bend on welded joints
4.4.3.1 The bend sample shall be taken from the welded pipe and tube or
welded test plate. The welded test plate shall be the same designation, the
same heat number, the same welding process, and the same heat treatment
system as the welded pipe and tube. A set of bend tests shall include a positive
bend and a back bend (i.e., the outer weld and the inner weld of the welded
pipe and tube are respectively at the maximum curved surface). For welded
pipes and tubes with a nominal wall thickness greater than 10 mm, a set of two
side bends may be adopted instead of a positive bend and a back bend.
4.4.3.2 In the bend test, the bend core diameter is 4 times the sample thickness;
the bend angle is 180°. After bending, in the weld area, there shall be no cracks
or gaps.
4.5 Grain size
The average grain size of base metal of the welded pipes and tubes shall be
determined in accordance with product standards or contract requirements.
4.6 Intergranular corrosion
The intergranular corrosion test results of the welded pipes and tubes shall be
judged according to product standards or contract requirements. The samples
shall include the weld, the heat-affected zone, and the base metal.
4.7 Nonmetallic inclusions
Nonmetallic inclusions of base metal of the welded pipes and tubes shall
comply with product standards or contract requirements.
4.8 Compactness
4.8.1 Hydrostatic pressure test
When the welded pipes and tubes are subjected to a hydrostatic pressure test,
the test pressure is calculated according to formula (3). The maximum test
pressure is 20 MPa. Under the test pressure, the pressure holding time shall
be no less than 5 s. The welded pipe and tube shall not leak.
the minimum wall thickness are allowed.
4.11.2 After the surface defects of the welded pipes and tubes are repaired, it
shall carry out liquid penetrant inspection. The inspection results shall comply
with the product standard or the contract.
5 Test methods
5.1 The inspection items and test methods of welded pipes and tubes shall
comply with the requirements of Table 3.
5.2 The inner and outer surfaces of the welded pipes and tubes shall, under full
lighting conditions, be visually inspected one by one. The liquid penetrant
inspection shall be carried out in accordance with the provisions of NB/T
47013.5-2015.
5.3 The dimensions and shape of the welded pipes and tubes shall be
measured one by one using the measuring tools which meet the accuracy
requirements. For welded pipes and tubes with a nominal outer diameter of not
less than 508 mm, the outer diameter shall be measured using a diameter tape
measure.
Table 3 -- Inspection items, sampling quantities, sampling locations, and
test methods
No. Inspection items
Sampling
quantities Sampling locations Test methods
1 Chemical composition 1/furnace GB/T 20066
GB/T 223 (all parts), GB/T
8647 (all parts), GB/T 11170,
GB/T 20123, GB/T 20125
2 Tensile test 1/lot On any welded pipe and tube, GB/T 2975 GB/T 228.1
3 Tensile test on welded joints 1/lot
On any welded pipe and
tube, GB/T 2651 GB/T 2651
4 Delivery hardness 1/lot
On any welded pipe and
tube
GB/T 230.1, GB/T 231.1,
GB/T 4340.1
5 Flattening test 1/lot On any welded pipe and tube GB/T 246
6 Drift-expanding test 1/lot
On any welded pipe and
tube GB/T 242
7 Bend on welded joints
TAKE one set of
2 samples per lot
On different welded
pipes and tubes GB/T 2653
8 Grain size 1/lot On any welded pipe and tube GB/T 6394
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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