GB/T 18442.7-2017 PDF in English
GB/T 18442.7-2017 (GB/T18442.7-2017, GBT 18442.7-2017, GBT18442.7-2017)
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Static vacuum insulated cryogenic pressure vessels -- Part 7: Rules of pressure strengthening for inner vessels
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Standards related to (historical): GB/T 18442.7-2017
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GB/T 18442.7-2017: PDF in English (GBT 18442.7-2017) GB/T 18442.7-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.40
A 82
Static vacuum insulated cryogenic pressure vessels - Part
7. Rules of pressure strengthening for inner vessels
ISSUED ON. NOVEMBER 01, 2017
IMPLEMENTED ON. MAY 01, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms, definitions and symbols ... 6
4 General requirements ... 7
5 Material ... 7
6 Design ... 9
7 Manufacture and inspection ... 11
Annex A (informative) Important quality control points during manufacturing
process of pressure strengthening inner vessels ... 18
Annex B (informative) Approximate control and requirements of Austenitic
stainless-steel number ... 20
Annex C (informative) Requirements for test of pressure strengthening process
verification ... 21
Annex D (informative) Test piece pre-tensile and test rules ... 27
Annex E (normative) Pressure strengthening treatment ... 31
Static vacuum insulated cryogenic pressure vessels - Part
7. Rules of pressure strengthening for inner vessels
1 Scope
This Part of GB/T 18442 specifies the technical requirements for material,
design, manufacture and inspection of the inner vessels of static vacuum
insulated cryogenic pressure vessels (hereinafter referred to as the inner
vessels) that are manufactured by pressure strengthening technology.
This Part is applicable the inner vessels that meet the following conditions at
the same time.
a) in accordance with the provisions of 1.2 of GB/T 18442.1, the medium is
frozen liquefied gas;
b) the material is austenitic stainless steel;
c) the nominal thickness is not less than 4mm and not more than 24mm,
consisting of a single diameter cylinder and a standard oval head;
d) the strain strengthening is completed at room temperature.
This Part is not applicable to the inner vessels that contain mediums of which
the toxicity hazard is moderate and above.
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 150 (all parts), Pressure vessels
GB/T 228.1, Metallic materials - Tensile testing - Part 1. Method of test at
room temperature
GB/T 229, Metallic Materials - Charpy Pendulum Impact Test Method
GB/T 232, Metallic materials - Bend test
GB/T 2653, Methods of bend and compression tests for welded joint
GB/T 3808, Verification of pendulum-type impact testing machines
GB/T 12160, Calibration of extensometers used in uniaxial testing
GB/T 14976, Seamless stainless-steel pipes for fluid transport
GB/T 16825.1, Verification of static uniaxial testing machines - Part 1.
Tension/compression testing machines - Verification and calibration of the
force-measuring system
GB/T 18442.1~18442.6, Part 1~Part 6 of Stationary Vacuum Thermal-
Insulating Cryogenic Pressure Vessel
GB/T 24511, Stainless steel and heat resisting steel plate, sheet and strip for
pressure equipment
NB/T 47010, Stainless and heat-resisting steel forgings for pressure
equipment
NB/T 47013.2, Nondestructive testing of pressure equipment Part 2.
Radiographic testing
NB/T 47013.5, Nondestructive testing of pressure equipment Part 5.
Penetrant testing
NB/T 47013.11, Nondestructive Testing of Pressure Equipment Part 11.
Standard practice for X-ray digital radiography
NB/T 47014, Welding procedure qualification for pressure equipment
NB/T 47016, Mechanical Property Tests of Product Welded Test Coupons for
Pressure Equipment
NB/T 47018.1, Technical permission of welding materials for pressure
equipment - Part 1. General rule
NB/T 47018.2, Technical permission of welding materials for pressure
equipment - Part 2. Electrodes for steel
NB/T 47018.3, Technical permission of welding materials for pressure
equipment - Part 3. Steel electrodes and rods for gas shielded arc welding
NB/T 47018.4, Technical permission of welding materials for pressure
equipment - Part 4. Electrodes and fluxes for submerged arc welding
JB 4732-1995, Steel Pressure Vessels - Design by Analysis (confirmed in
2005)
4 General requirements
4.1 In addition to all parts of this Standard, the material, design, manufacture
and inspection as well as marks of the inner vessels shall also comply with the
relevant laws, regulations, safety technical specifications and relevant
standards promulgated by the country.
4.2 When the inner vessels manufactured by pressure strengthening
technology beyond the scope of this Part, it shall be implemented in accordance
with the relevant provisions of TSG 21.
4.3 The manufacturer shall carry out the manufacture of the inner vessels in its
organization, verify the welding process and pressure strengthening process
adopted by it, and be responsible for the correctness and completeness of the
process documents.
4.4 The manufacturer shall upload the mechanical performance data of the
welded test piece and the data of the pressure strengthening test process to
the national strain-enhanced cryogenic container manufacturing information
public service platform.
4.5 The special equipment supervision and inspection agency shall supervise
and inspect the pressure strengthening process adopted by the inner vessels
and the important quality control points proposed in Annex A, which shall meet
the requirements of this Part.
5 Material
5.1 Steel plate
5.1.1 The designation and mechanical properties of the steel plate shall comply
with the requirements of Table 1. The supply status is solid solution heat
treatment and meets the requirements of GB/T 150.2 and GB/T 24511.
5.1.2 The steel plate shall be re-inspected. It shall at least contain the following
information.
a) Check the surface quality and material marking of the steel plate one by
one;
b) Re-inspect the tensile properties of steel plate at room temperature;
c) If the open plate is used, the re-inspection requirements shall also comply
with the relevant provisions of GB/T 150.4.
5.1.3 The sampling quantity and position of tensile test shall be in accordance
When using the materials other than Table 1 and Table B.1 to manufacture the
inner vessels with the pressure strengthening technology, it shall also comply
with the relevant provisions of TSG 21.
6 Design
6.1 General
6.1.1 In addition to the provisions of this Part, the design of the inner vessels
shall also comply with the provisions of TSG 21, GB/T 150 and GB/T 18442.3.
6.1.2 The designer shall issue a risk assessment report for the vacuum
insulated cryogenic pressure vessels manufactured by pressure strengthening
technology. The content of the report, in addition to the provisions of GB/T 150.1,
shall also include the failure mode as well as risk control caused by pressure
strengthening technology.
6.1.3 The design of the inner vessels shall indicate "using pressure
strengthening technology", as well as strengthening pressure, diameter before
strengthening.
6.1.4 The diameter and thickness of the inner vessel involved in this chapter
are the parameters before the pressure strengthening treatment. Does not
consider changes after pressure strengthening treatment.
6.1.5 The product nameplate shall be marked with “pressure strengthening
vessel”, the symbol is “PS”.
6.2 Load
6.2.1 When designing the inner vessel, the corresponding load and its
combination shall be considered in accordance with the provisions of GB/T
18442.3.
6.2.2 In the process of pressure strengthening treatment, the reaction force and
the strengthening pressure load generated at the support of the inner vessel
shall also be considered.
6.3 Allowable stress
6.3.1 The allowable stress of the steel plate for the cylinder and the head is
determined according to Table 2.
6.3.2 The allowable stress of pressure components such as adapters and
forgings is determined according to GB/T 150.2.
6.3.3 When the local stress of the adapters, the inner vessel supports and the
6.8 Pressure of pressure resistance test
The pressure of pressure resistance test shall comply with the provisions of
GB/T 18442.3.
6.9 Pressure of leak test
Perform according to the provisions of GB/T 18442.3.
6.10 Structure design
6.10.1 Except the last closed ring welds, the type A and type B weld joints shall
be full penetration butt joints. Closed ring welds allow the use of butt joints with
permanent backing.
6.10.2 The hole-opening diameter of the inner vessel shall not be greater than
150 mm. When setting the craft manhole, the edge of the hole shall be within
0.8 Di of the center of the head. The center line of the opening is along the
normal direction of the housing.
6.10.3 The splicing weld of the reinforcing ring shall be a full-section penetration
weld joint. The weld between the reinforcing ring and the cylinder shall be
continuously welded on both sides. The height of the solder fillet shall not be
less than the thickness of the cylinder and the thickness of the reinforcing ring.
6.10.4 An overflow shall be placed on the inner vessel at the rated full rate.
When determining the rated full rate, the inner volume of the inner vessel before
pressure strengthening is generally used.
6.10.5 In the design of the structure, the influence of the plastic deformation of
the inner vessel on the low-temperature insulation performance of the vessel,
the installation of the outer casing and the piping system shall also be
considered.
7 Manufacture and inspection
7.1 General
7.1.1 In addition to the provisions of this Part, the manufacture, inspection and
acceptance of the inner vessels shall also meet the requirements of other parts
of GB/T 18442 and design documents.
7.1.2 The manufacturer shall have plant facilities, strengthening equipment and
corresponding testing equipment suitable for the pressure strengthening
process.
7.1.3 Before the manufacturer uses the pressure strengthening technology for
7.4.4.2 The second pressure strengthening treatment can be exempted when
welding is applied under the following conditions. But it shall carry out the
pressure resistance test. The test pressure shall be determined according to
6.8.
a) only withstand the spot welding of small load accessories;
b) the length of the weld seam of adapter is not more than 10% of the inner
diameter of the inner vessel, and not exceed 100mm;
c) slight welding rework does not have significant impact on the main
structure.
7.4.5 Product welding test piece
7.4.5.1 The product welding test piece shall be prepared piece by piece. The
test piece shall be welded at the same time at the extension of the longitudinal
weld of the cylinder section and at the cylinder section. Before strengthening,
perform longitudinal welding for the inner vessel of which the geometric volume
is less than or equal to 5 m3. When using the same welding process, it is allowed
to prepare product welding test pieces by batch. The inner vessels of same
model, of same lot, of same material designation, of same welding process and
of same strengthening process can be batched. Each batch does not exceed
20 pieces.
7.4.5.2 Product welding test pieces shall be pre-tensile according to the
provisions of Annex D. The number of welding test pieces and samples of the
product shall comply with the provisions of NB/T 47016. The tensile at room
temperature test, the bending at room temperature test and low temperature
impact (not higher than the minimum design metal temperature) test after pre-
tensile as well as their qualification indicators shall comply with the provisions
of Table 3.
7.5 Nondestructive testing
7.5.1 Testing before pressure strengthening implementation
a) All type A, B weld joints of inner vessels shall be subjected to 100%
radiation testing according to NB/T 47013.2 or NB/T 47013.11. The testing
technology level is not lower than AB level. Except that the qualification
level of the closed weld joint with the backing plate is not lower than level
II, the qualification level of the other weld joints is not lower than level I.
b) Stress concentration parts such as inner vessel types A, B, D, E weld joints
as well as strengthening circle and corner joint weld joint of inner vessels
shall be subjected to 100% penetration test according to NB/T 47013.5.
The qualification level is not less than level I.
Annex A
(informative)
Important quality control points during manufacturing process of
pressure strengthening inner vessels
A.1 Design documents
A.1.1 Risk assessment report.
A.1.2 Document integrity and standard compliance.
A.1.3 "PS" logo in design documents.
A.2 Material retesting
A.2.1 Inner vessel materials shall meet the requirements of Clause 5.
A.2.2 The materials of the cylinder and the head shall also comply with the
provisions of 7.2.
A.3 Forming control
A.3.1 The forming of the cylinder and the head shall comply with the provisions
of 7.3.
A.3.2 The shape and size of the weld seam shall comply with the provisions of
7.4.2.
A.4 Welding procedure assessment
Welding procedure assessment shall comply with the provisions of 7.4.1. The
mechanical properties and bending performance of the weld joints after pre-
tensile shall be in accordance with the requirements of Table 3.
A.5 Welding
A.5.1 Weld according to the qualified welding process.
A.5.2 The selection of welding consumables shall comply with the provisions of
5.4.
A.6 Product welding test piece
Product welding test piece shall comply with the provisions of 7.4.5. The
mechanical properties and bending performance indicators shall meet the
Annex C
(informative)
Requirements for test of pressure strengthening process verification
C.1 General
C.1.1 The process documentation of the inner vessel shall be verified by
process validation test before manufacturing. The verification test uses trial
sample vessel. Perform relevant test according to the requirements of Annex D.
C.1.2 The design, manufacture and inspection of the sample vessel shall be in
accordance with the requirements of this Standard. And before the trial
production, the welding process qualification is carried out according to the
requirements of this Part and related standards. Develop process documents
such as welding procedure instructions, pressure strengthening process
instructions, and test outlines.
C.1.3 The relevant requirements of the verification test shall be in accordance
with the content and requirements of the test program.
C.2 Structure requirements for sample vessel
C.2.1 The structure requirements for sample vessel are as follows.
a) The tank body has at least 2 cylinder sections. The width of each section
is not less than 1500 mm. The butt ring is set to the weld at the maximum
deformation of the estimated inner vessel.
b) The inner diameter is not less than 1800 mm. The nominal wall thickness
is not less than 8 mm.
c) The tank body does not have binding parts such as reinforcement rings,
manholes, and support pads.
d) The butt joint weld seam of the cylinder and the head shall be capable of
simulating the weld joint form of the joint closed weld seam of the inner
vessel.
C.2.2 The strength calculation shall be performed for the structure and design
parameters of sample vessel.
C.2.3 The numerical simulation shall be performed for pressure strengthening
process of sample vessel. By comparing with the test results, the rules of the
plastic deformation of the cylinder and the deformation amount caused by the
located in the middle of the parallel section of the sample. The thickness of the
sample shall be equal to or close to the thickness of the sample base material.
When the thickness of the base material on both sides of the weld seam is
inconsistent, the thickness of the sample shall be consistent with the thinner
side.
D.3.2 Tensile method at room temperature
The tensile test at room temperature shall be carried out according to the
requirements of GB/T 228.1.
D.4 Impact sample and test method
D.4.1 Impact sample
D.4.1.1 Prepare a Charpy V-notch impact sample with dimensions of 10mm ×
10mm × 55mm. It is also possible to prepare a Charpy V-notch impact sample
having a size of 7.5mm × 10mm × 55mm or 5mm × 10mm × 55mm according
to the thickness of the test piece. The impact sample shall comply with the
provisions of GB/T 229.
D.4.1.2 The V-notch of each impact sample is measured with a dedicated notch
projector. Carry out the test after it is qualified.
D.4.2 Impact test method
The impact test method shall comply with the provisions of GB/T 229.
D.4.3 Sample cooling
When the sample is subjected to the impact test, it shall be cooled to the
specified temperature. The holding time is not less than 5 min.
D.5 Bending sample and test method
D.5.1 Bending sample
The thickness of the bending sample is the original thickness of the sample.
The weld seam shall be located at the center of the sample. And remove the
weld seam reinforcement. When the surface of the sample needs to be leveled,
the thickness of the sample shall be as close as possible to the thickness of the
test piece. The length L of the sample is 200 mm and the width W is 38 mm,
see Figure D.2.
Annex E
(normative)
Pressure strengthening treatment
E.1 Pressure strengthening treatment
E.1.1 General
E.1.1.1 The pressure strengthening site shall have reliable safety protection
facilities and be approved by the organization technical person in charge and
the safety department. During the pressure strengthening process, the test site
shall not perform work unrelated to the test, and unrelated personnel shall not
stay at the test site.
E.1.1.2 The inner vessels shall meet the requirements of this Part and the
design documents.
E.1.1.3 Parts welded to the inner vessel shall be welded before strengthening.
E.1.1.4 Before the pressure strengthening is implemented, the weld joint shall
pass the non-destructive test according to the requirements of 7.5.
E.1.1.5 The chloride ion content in pressure strengthening water does not
exceed 25 mg/L.
E.1.1.6 The top of the inner vessel (the highest part) shall be provided with an
exhaust pipe. The filling port is located at the bottom of the inner vessel. When
pressure is strengthened, the setting of the support shall not affect the
deformation of the inner vessel. After filling the container with water, wait at least
15 min for the gas dissolved in the water to drain completely.
E.1.1.7 The outer surface of the inner vessel shall be kept dry during the
pressure strengthening process. After the strengthening is completed, the water
shall be drained and dried.
E.1.1.8 Special equipment supervision and inspection institutions shall witness
and test the pressure strengthening process. And sign the confirmation in the s
pressure strengthening report.
E.1.2 Testing equipment and control system
E.1.2.1 The pressure gauge accuracy shall be no less than level 1.6. The
number of pressure gauges shall be no less than 2. The range of the pressure
gauge shall be 1.5 times to 3.0 times the strengthening pressure. The pressure
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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