GB/T 39754-2021 PDF English
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Hot dip coating steel sheet and strip for corrugated pipe
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GB/T 39754-2021: PDF in English (GBT 39754-2021) GB/T 39754-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.50
H 46
Hot dip coating steel sheet and strip for corrugated
pipe
ISSUED ON: MARCH 09, 2021
IMPLEMENTED ON: OCTOBER 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 Terms and definitions ... 6
4 Classification and codes ... 7
5 Order content ... 8
6 Dimensions, appearance and weight ... 9
7 Technical requirements ... 9
8 Test methods ... 13
9 Inspection rules ... 14
10 Packaging, marks and quality certificate ... 15
Hot dip coating steel sheet and strip for corrugated
pipe
1 Scope
This Standard specifies terms and definitions, classification and codes,
dimensions, appearance, weight, technical requirements, test methods,
inspection rules, packaging, marks and quality certificates for hot dip coating
steel sheet and strip for corrugated pipe (hereinafter referred to as steel sheet
and strip).
This Standard is applicable to the hot dip coating steel sheet and strip, with a
thickness of 0.7mm~10mm, for corrugated steel structure that is used in the
production of pipe networks, culverts, underground water storage tanks,
pedestrian walkways, underpasses for automobiles, public pipe corridors and
special-shaped structures installed on site.
NOTE: Under various conditions of use, according to the bearing load of various
corrugated pipes, reasonably design the corrugation type, steel sheet thickness and
strength, foundation and backfill type, factory manufacturing control and installation of the
corrugated pipes. For corrugated steel pipes in different use environments, according to
the actual environment and service life requirements, reasonably select the coating type
and coating weight or thickness.
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 222, Permissible tolerances for chemical composition of steel products
GB/T 223.5, Steel and iron - Determination of acid-soluble silicon and total
silicon content - Reduced molybdosilicate spectrophotometric method
GB/T 223.9, Iron steel and alloy - Determination of aluminium content -
Chrome azurol S photometric method
GB/T 223.59, Iron, Steel and Alloy - Determination of Phosphorus Content -
Bismuth Phosphomolybdate Blue Spectrophotometric Method and Antimony
Phosphomolybdate Blue Spectrophotometric Method
on dimensions shape and weight
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 hot-dip zinc coating; Z
a coating that is obtained by immersing the pre-treated steel strip or steel sheet
in a molten zinc solution of which the zinc content is not less than 99%
3.2 aluminum-silicon coating; AS
a coating that is obtained by immersing the pretreated steel strip or steel sheet
in a plating solution of which the aluminum content is 90%±2% and the silicon
content is 10%±2%
3.3 aluminum-zinc alloy coating; AZ
a coating that is obtained by immersing the treated steel strip or steel sheet in
a plating solution of which the aluminum content is 55%±3%, the silicon content
is 1.6%±0.3%, and the balance is zinc
3.4 base steel thickness
the thickness of steel sheet substrate without metal coating or other coating
3.5 corrugated steel pipe; CSP
a coated steel strip or steel sheet is processed into a corrugated steel pipe
3.6 corrugated steel pipe sheet
a steel sheet or strip that is used to produce corrugated steel pipe (structural
corrugated steel pipe, spiral corrugated steel pipe) with coating
3.7 corrugated steel pipe
a large size steel pipe of which the hot-rolled steel sheet is pickled and then
rolled into a corrugated sheet, which is hot-dip galvanized or hot-dipped with
other coatings by the solvent method, and then assembled with these coated
corrugated steel sheets
NOTE: Hot-rolled steel sheet is usually used.
3.8 helical corrugated steel pipe
a steel pipe that is made of coated steel strip through spiral winding process
NOTE: Include various coated helical corrugated steel pipes, corrugated pipes of special
material and corrugated pipes of various structures, such as carbon steel corrugated pipes,
weather resistant corrugated pipe, stainless steel corrugated pipes.
4 Classification and codes
4.1 Codes
4.1.1 Usage code
The usage code is the initial letter "B" of the Chinese pinyin of the word "Bo"
(meaning corrugated in English) in "Bo Wen Guan" (meaning corrugated pipe).
4.1.2 Steel grade code
If the second letter of the steel grade code is C, it represents that the base steel
is specified as a cold-rolled base steel. If the second letter is D, it represents
that the base steel is specified as a hot-rolled base steel.
4.1.3 Coating type code
The pure zinc coating is expressed as Z. The aluminum-zinc coating is
expressed as AZ. The aluminum-silicon coating is expressed as AS.
4.2 Expression method for designation
The designation of steel sheet and strip is composed of four parts: product
usage code, steel grade code, specified minimum tensile strength value and
coating type code. The specified minimum tensile strength value and the
coating type code are connected with a plus sign "+".
Example 1: BC290+Z
It means that the product is steel for corrugated pipes, the base steel is cold-rolled, the
minimum tensile strength specified is 290MPa, and is a zinc-coated product.
Example 2: BD380+AZ
It means that the product is steel for corrugated pipes, the base steel is hot-rolled, the
minimum specified tensile strength is 380MPa, and is a aluminum-zinc coating product.
4.3 Designation and recommended usage
The designation and usage of steel sheet and strip shall comply with Table 1.
7.8.1 For the coating surface that needs further coating treatment, try to avoid
oiling to avoid affecting the effect of subsequent coating. Under normal
packaging, transportation, handling and storage conditions, the supplier shall
ensure that within 6 months from the date of completion of manufacturing, the
steel sheet and strip will not produce black rust on the surface.
NOTE: Usually, the issuance date in the product inspection document is specified as the
product's manufacturing completion date.
7.8.2 During the transportation or storage of steel sheet and strip, all surface
treatment methods can only provide temporary protection to the product surface.
The surface color of the product may change.
7.8.3 The purchaser shall choose the appropriate surface treatment method
according to its own product processing technology, coating method and other
specific conditions. Try to minimize the storage time of steel sheet and strip.
7.8.4 Choose the right surface treatment. It may reduce the tendency of black
rust and friction marks during transportation and storage. At the same time, it
can improve the adhesion of the painted layer in the subsequent processing
and protect the coating.
7.8.5 If the purchaser requires that the surface is not treated (U), it shall be
specified in the contract. For surface defects such as black rust, scratches and
friction marks during the handling, storage and use of this type of product, the
supplier will not bear the corresponding product quality responsibility.
7.9 Surface treatment method
7.9.1 Chromic acid passivation (C), trivalent chromium passivation (C3)
and chromium-free passivation (CN)
The surface treatment can reduce the black rust on the surface of the product
during transportation and storage. When using chromic acid passivation
treatment, there is a risk of rubbing black spots on the surface. During trivalent
chromium passivation treatment, hexavalent chromium substances harmful to
human health in the passivation film is restricted. During chromium-free
passivation treatment, the passivation film does not contain chromium and
chromium ions.
7.9.2 Chromic acid passivation + oiling (CO), trivalent chromium
passivation + oiling (CO3) and chromium-free passivation + oiling (CON)
The surface treatment can further reduce the black rust on the surface of the
product during transportation and storage. During trivalent chromium
passivation treatment, the hexavalent chromium substances harmful to human
health in the passivation film is restricted. During chromium-free passivation
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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