GB/T 38512-2020 English PDF (GBT38512-2020)

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GB/T 38512-2020: Aluminum and aluminum alloy tubes for the pressure vessel
GB/T 38512-2020
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.150.10
H 61
Aluminum and aluminum alloy tubes for the pressure
vessel
ISSUED ON: MARCH 06, 2020
IMPLEMENTED ON: FEBRUARY 01, 2021
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 Requirements ... 5 
4 Test methods ... 9 
5 Inspection rules ... 11 
6 Marks, packaging, transport, storage and quality certificate ... 14 
7 Order sheet (or contract) content ... 16 
Annex A (informative) Welding performance of the tubes ... 17 
Bibliography ... 18 
Aluminum and aluminum alloy tubes for the pressure
vessel
1 Scope
This Standard specifies requirements, test methods, inspection rules and marks,
packaging, transportation, storage and quality certificate as well as order sheet
(or contract) content of aluminum and aluminum alloy tubes for the pressure
vessel.
This Standard is applicable to aluminum and aluminum alloy tubes for the
pressure vessel (hereinafter referred to as “the 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 230 (all parts), Metallic Rockwell hardness test
GB/T 231 (all parts), Metallic Brinell hardness test
GB/T 3190, Wrought aluminum and aluminum alloys - Chemical composition
limits
GB/T 3199, Wrought Aluminum and Aluminum Alloy Products - Packing,
Marking, Transporting and Storing
GB/T 3246.1, Inspection method for structure of wrought aluminum and
aluminum alloy products - Part 1: Inspection method for microstructure
GB/T 3246.2, Inspection method for structure of wrought aluminum and
aluminum alloy products - Part 2: Inspection method for macrostructure
GB/T 4436-2012, Wrought aluminum and aluminum alloy tubes - Dimensions
and deviations
GB/T 6519, Process for ultrasonic inspection of wrought aluminum alloy
products
GB/T 7999, Optical emission spectrometric analysis method of aluminum
3.1.2 Marking example
The mark of the tubes is expressed in the order of product name, reference to
this Standard, designation, state, size specification.
Example: The fixed-scale tube of which the designation is 5083, the state is O,
the outer diameter is 40.00mm, the wall thickness is 6.00, the length is 4000, is
marked as:
Tube GB/T 38512-5083 O-40.00×6.00×4000.
3.2 Chemical composition
The chemical composition of the tube shall comply with the provisions of GB/T
3190.
3.3 Size deviation
3.3.1 Outer diameter, curvature
The outer diameter, curvature of the tube shall comply with the provisions on
high precision in GB/T 4436-2012.
3.3.2 Wall thickness
The wall thickness deviation of the tube shall comply with the provisions of GB/T
4436-2012.
3.3.3 Length
The fixed-scale length deviation of the tube shall comply with the provisions on
high precision in GB/T 4436-2012. For the tubes that are delivered in double-
scale as the fixed-scale, 5mm cutting capacity shall be left for each sawing edge.
3.3.4 Cutting slope
There shall be no burrs at both ends of the tube. The cutting slope shall meet
the provisions on high precision level in GB/T 4436-2012.
3.3.5 Others
If the purchaser has other requirements, it shall be indicated in the order sheet
(or contract).
3.4 Tensile mechanical properties at room temperature
The longitudinal tensile mechanical properties of the tube at room temperature
shall meet the requirements of Table 2. For the tubes of which the wall thickness
exceeds the one specified in Table 2, the mechanical properties are determined
3.10 Macrostructure
3.10.1 Cracks, tailing, pores, and bright grains are not allowed on the
macrostructure sample of the tube.
3.10.2 Non-metallic inclusions, compound segregation or intermetallic
compounds are not allowed on the macrostructure samples of the tube.
3.10.3 The depth of the coarse crystal ring shall be agreed between the supplier
and the purchaser and indicated in the drawing or order sheet (or contract).
3.10.4 For the tube that wall thickness requires positive and negative symmetric
deviation, the layering depth on the macrostructure sample shall not exceed the
negative deviation of the tube wall thickness and the wall thickness deviation of
the tube shall not exceed the allowable range. For the tube that wall thickness
requires non-positive and negative symmetry deviation, the layering depth on
the macrostructure sample shall not exceed half of the allowable deviation of
the tube wall thickness. After deducting the thickness of the layer thickness, the
size deviation shall not exceed the allowable range.
3.11 Microstructure
The microstructure of the quenched product is not allowed to burn.
3.12 Appearance quality
3.12.1 The surface of the tube shall be smooth, and no cracks, corrosion or
foreign inclusions are allowed.
3.12.2 The surface of the tube is allowed to have local defects such as slight
peeling, bubbles, scrapes, scratches, bumps, pits that do not affect the use.
After deducting the depth of the defect, the wall thickness deviation shall not
exceed the allowable range.
3.13 Others
When welding pipes, the mechanical properties of the welds are in Annex A.
4 Test methods
4.1 Chemical composition
4.1.1 The chemical composition analysis method shall be carried out according
to GB/T 20975 or GB/T 7999. The arbitration analysis shall use the method
specified in GB/T 20975.
4.1.2 "Al" content is calculated according to the method specified in GB/T 3190.
4.8 Pressure resistance
The test method for pressure resistance of the tube shall be negotiated between
the supplier and the purchaser and indicated in the order sheet (or contract).
4.9 Macrostructure
The inspection method for the macrostructure of the tube shall be in accordance
with GB/T 3246.2.
4.10 Microstructure
The inspection method of the microstructure of the tube shall be in accordance
with GB/T 3246.1.
4.11 Appearance quality
Visually check the appearance quality under natural scattered light. If necessary,
the size measurement tool can be used to define the size of the defect, and the
depth of the defect can be determined by grinding.
4.12 Others
Refer to Annex A for the inspection method of weld mechanical properties.
5 Inspection rules
5.1 Inspection and acceptance
5.1.1 The product shall be inspected by the supplier to ensure that the product
quality meets the requirements of this Standard and the order sheet (or contract)
and fill in the quality certificate.
5.1.2 The purchaser shall inspect the received products in accordance with this
Standard. When the inspection result is inconsistent with the provisions of this
Standard and the order sheet (or contract), it shall be submitted to the supplier
in written form and resolved by consultation between the supplier and the
purchaser. Objections pertaining to surface quality and dimensional deviations
shall be raised within one month from the date of receipt of the product.
Objections that belong to other properties shall be raised within three months
from the date of receipt of the product. If arbitration is required, the organiza...