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GB/T 5237 consists of the following six parts under the general title Wrought aluminium alloy extruded profiles for architecture:
——Part 1: Mill finish profiles;
——Part 2: Anodized profiles;
——Part 3: Electrodeposition coating profiles;
——Part 4: Powder coating profiles;
——Part 5: Paint coating profiles;
——Part 6: Thermal barrier profiles.
This is Part 4 of GB/T 5237.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB 5237.4-2008 Wrought aluminium alloy extruded profiles for architecture — Part 4: Powder coating profiles. In addition to editorial changes, the following main technical modifications pf this part has been made with respect to GB 5237.4-2008:
——The standard name has been modified (see cover hereof; cover of Edition 2008);
——The statement of “Article 4.5.3.1 and Article 4.5.5 in this Part of the standard are mandatory and the others are recommendatory” in the Foreword have been deleted (see the Foreword in Edition 2008);
——The applicable “scope” of this part has been modified (see Clause 1; Clause 1 in Edition 2008);
——Normative reference GB/T 228-2002 has been deleted (see Clause 2 and Subclause 5.2 in Edition 2008);
——Normative reference JC/T 480 has been deleted (see Clause 2 and 5.4.12 in Edition 2008);
——Normative reference GB/T 16585 has been deleted (see Clause 2 in Edition 2008);
——Normative reference GB/T 5237.2 has been added (see Clause 2 and 7.3);
——Normative reference GB/T 8005.3 has been added (see Clauses 2 and 3);
——Normative reference GB/T 14684 has been added (see Clause 2 and 5. 4.12);
——Normative reference JC/T 479 has been added (see Clause 2);
——Normative reference YS/T 680-2016 has been added (see Clause 2 and Annex A);
——Normative reference GB/T 1865-1997 has been modified to GB/T 1865-2009 (see Clause 2 and 5.4.18.1; 2 and 5.4.17.1 in Edition 2008);
——Normative reference GB/T 8013.3-2007 has been modified to a normative reference without a year number (see Clause 2, 4.6.19, 5.4.10, 5.4.13, 5.4.19 and 6.5; Clause 2, 3, 4.2, 4.5.18, 5.4.18 and 6.4 in Edition 2008)
——Normative reference GB/T 26323 has been added (see Clause 2 and 5.4.16);
——Introduction of "Terms and Definitions" has been modified (see Clause 3; Clause 3 in Edition 2008);
——The definition of “exposed surfaces” has been modified (see 3.1; 3.2 in Edition 2008);
——The definition of “coating" has been deleted (see 3.1 in Edition 2008);
——The definition of “local thickness” has been deleted (see 3.3 in Edition 2008);
——The definition of “minimum local thickness" has been deleted (see 3.4 in Edition 2008);
——The content of "types and characteristics of coatings" has been added in product classification (see 4.1.2);
——The content of "coating appearance effect” has been added in product classification (see 4.1.3);
——The content of "property grade of coating and applicable environment of corresponding profiles" has been added in product classification (see 4.1.4);
——The content of "quality assurance" has been added (see 4.2);
——The specifications and test method requirements for boiling water resistance have been modified (see 4.6.6 and 5.4.6; 4.5.10 and 5.4.10 in Edition 2008);
——The specifications and test method requirements for impact resistance have been modified (see 4.6.7 and 5.4.7; 4.5.6 and 5.4.6 of Edition 2008);
——The specifications and test method requirements for cupping resistance have been modified (see 4.6.8 and 5.4.8; 4.5.7 and 5.4.7 of Edition 2008);
——The specifications and test method requirements for bending resistance have been modified (see 4.6.9 and 5.4.9; 4.5.8 and 5.4.8 of Edition 2008);
——The specifications for salt-spray resistance have been modified (see 4.6.15; 4.5.15 of Edition 2008);
——The specifications and test method requirements for filiform corrosion resistance have been added (see 4.6.16 and 5.4.16);
——The specifications for heat and humidity resistance have been modified (see 4.6.17; 4.5.16 of Edition 2008);
——The specifications for accelerated weatherability have been modified (see 4.6.18.1; 4.5.17.1 in Edition 2008);
——The specifications for natural weatherability have been modified (see 4.6.18.2; 4.5.17.2 in Edition 2008);
——The test method requirements for chemical composition have been modified (see 5.1; 5.1 in Edition 2008);
——The test method requirements for mechanical properties have been modified (see 5.2; 5.2 in Edition 2008);
——The test method requirements for wear resistance have been modified (see 5.4.10; 5.4.9 in Edition 2008);
——The test method requirements for solvent resistance have been modified (see 5.4.13; 5.4.13 in Edition 2008);
——The requirement of "marking width is 1 min" has been added in the salt-spay corrosion resistance test method (see 5.4.15, Edition 2008 5.4.15);
——The batching method has been modified (see 6.2; 6.2 in Edition 2008);
——The inspection classification has been added (see 6.3);
——The requirements for inspection items have been modified (see 6.4; 6.3 in Edition 2008);
——The process guaranteed items have been added (see 6.4);
——The sampling procedures have been modified (see 6.5; 6.4 in Edition 2008);
——The requirements for judgment of inspection results have been modified (see 6.6; 6.5 of Edition 2008);
——The requirements for marking have been modified (see 7.1; 7.1 in Edition 2008);
——The content requirements of quality certificate have been modified (see 7.4; 7.5 in Edition 2008);
——The content requirements of the order (or contract) have been modified (see Clause 8; Clause 8 in Edition 2008);
——The Annex for falling sand test method has been deleted (see Annex A of Edition 2008);
——The Annex for solvent-resistance test method has been deleted (see Annex B of Edition 2008);
——The Annex (informative) for quality assurance has been added (see Annex A).
——The content of bibliography has been added (see Bibliography).
This part was proposed by China Nonferrous Metals Industry Association.
This part is under the jurisdiction of SAC/TC 243 National Technical Committee on Nonferrous Metals of Standardization Administration of China.
The previous edition of this standard is as follows:
——GB/T 5237.4-2000, GB 5237.4-2004、GB 5237.4-2008。
Wrought aluminium alloy extruded profiles for architecture — Part 4: Powder coating profiles
1 Scope
This part of GB/T 5237 specifies the terms and definitions, requirements, test methods, inspection rules, marking, packaging, transportation, storage and quality certificate as well as content of the order (or contract) of power profiles.
This part is suitable for electrostatic powder coating profiles (hereinafter referred to as “the profiles”) for buildings with thermosetting polyester, polyurethane, trifluorovinyl chloride-vinyl ether (FEVE) powder and thermoplastic polyvinylidene fluoride (PVDF) powder as coatings.
Other aluminum alloy processed materials with the same application and surface treatment method may be implemented by reference to this part.
2 Normative references
The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1732 Determination of impact resistance of film
GB/T 1740 Determination of resistance to heat and humidity of paint films
GB/T 1865-2009 Paints and varnishes — Artificial weathering and exposure to artificial radiation — Exposure to filtered xenon-arc radiation
GB/T 3199 Wrought aluminium and aluminium alloy products — Packing marking transporting and storing
GB/T 4957 Non-conductive coatings on non-magnetic basis metals — Measurement of coating thickness — Eddy current
GB/T 5237.1 Wrought aluminium alloy extruded profiles for architecture — Part 1: Untreated profiles
GB/T 5237.2 Wrought aluminium alloy extruded profiles for architecture — Part 2: Anodized profiles
GB/T 668 Water for analytical laboratory use — Specification and test methods
GB/T 6742 Paints and varnishes — Bend test (cylindrical mandrel)
GB/T 8005.3 Aluminium of aluminium alloys — Terms and definitions — Part 3: Surface treatment terms
GB/T 8013.3 Anodic oxide coatings and organic polymer coatings on aluminium and its alloys — Part 3: Organic polymer coatings
GB/T 9275 Paint and varnishes ― Buchholz indentation test
GB/T 9276 Methods of exposure to natural weathering of coating
GB/T 9286 Paints and varnishes — Cross cut test for films
GB/T 9753 Paints and varnishes—Cupping test
GB/T 9754 Paints and varnishes — Determination of specular gloss of non-metallic paint films at 20°, 60°and 85°
GB/T 9761 Paints and varnishes — Visual comparison of the colour of paints
GB/T 10125 Corrosion Tests in Artificial Atmospheres — Salt Spray Tests
GB/T 11186.2 Methods for measuring the colour of paint films — Part 2: Colour measurement
GB/T 111863 Methods for measuring the colour of paint films — Part 3: Calculation of colour differences
GB/T 14684 Sand for construction
GB/T 17671 Method of testing cements — Determination of strength
GB/T 26323 Paints and varnishes — Determination of resistance to filiform corrosion on aluminium and aluminum alloy
JC/T 479 Building quicklime
YS/T 680-2016 Powder for coating aluminium alloy profiles for architecture
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB 80053 and the following apply.
3.1
exposed surfaces
visible surfaces (either in an open or closed state) of profiles being processed, manufactured and mounted onto a building
4 Requirements
4.1 Product classification
4.1.1 Designation, state, and dimensional specification
Designation, state and dimensional specification shall meet the requirements of GB/T 5237.1.
4.1.2 Coating types and characteristics
See Table 1 for the coating types and characteristics.
Table 1 Coating types and characteristics
Coating type Coating codea Coating characteristics
Polyester powder coating GA40 The coating is formed by spraying a powder paint with saturated carboxyl polyester as the main component, with better corrosion resistance and weatherability.
Polyurethane powder coating GU40 The coating is formed by spraying and curing a powder paint with saturated hydroxyl polyester as the main component, being smooth, high in abrasion resistance, and delicate in texture. When used in thermal transfer printing, its ink permeability is better than polyester coating.
Fluorocarbon powder coating GF40 The coating is formed by spraying and curing a powder paint with thermosetting FEVE resin or a powder paint with thermoplastic PVDF resin as the main component. It has better weatherability and is suitable for the environment with severe corrosive atmosphere and strong solar radiation.
Other powder coatings G040 See YS/T 680-2016
a The first English letter in the coating code represents power coating treatment; the second English letter indicates the powder type, in which A represents polyester powder, U polyurethane powder, F fluorocarbon powder and O other powders; the Arabic numerals behind the letters indicate the minimum local coating thickness limit.
4.1.3 Appearance effect of coating
The appearance effect of the coating is shown in Table 2.
Table 2 Appearance effect of coating
Appearance effect of coating Remarks
Plane effect The coating with low-gloss, flat-gloss and high-gloss features smooth surface and rich colors.
Texture
Effect Sand grain The coating surface has a stereoscopic effect. It is suitable for most aluminum door and window profiles, with the coating gloss no less than 5 gloss units. If the gloss of the coating is less than 5, it is difficult to guarantee the coating properties.
Wood grain Includes thermal transfer wood grain and secondary spraying wood grain, which has the appearance effect of tree texture. At present, the coating of thermal transfer wood grain is mainly suitable for the environment and indoors with low pollution and weak ultraviolet radiation. If applied outdoors, it is necessary to pay more attention to the strict control of powder quality, ink quality and process control. Secondary spraying wood grain has a stereoscopic effect and can be used outdoors.
Hammer grain, wrinkle, marble grain, 3D color carving Presents various good stereoscopic or artistic effects. However, the weatherability, acid and alkali resistance of these types of coatings are slightly poor, so they are mainly used indoors at present.
Metal effect The surface of the coating shall highlight the metallic texture or metallic flashing effect, but there are some limitations in the selection of pigment varieties and dosage, and the alkali resistance of the coating with aluminum pigment is slightly poor.
4.1.4 Performance grade of coating and applicable environment of corresponding profiles
According to the test results of accelerated weatherability, the property grade of the coating is divided into Grade I, Grade II and Grade III. The coating thickness grade shall be noted in the order (or contract), otherwise, material supplying is conducted according to Grade I. See Table 3 for the property grade of coating and applicable environment of corresponding profiles.
Table 3 Performance grade of coating and applicable environment of corresponding profiles
Performance grade of coating Applicable environment of profiles
Grade III Excellent weatherability, suitable for the environment with intensive solar radiation
Grade II Good weatherability, suitable for the environment with relatively strong solar radiation
Grade I General weatherability, suitable for the environment with general solar radiation intensity.
4.1.5 Marking example
Profiles are marked in the order of product name, part number, designation, state, section code and length, color (or color number), property grade of coating, and coating code name. Examples are given below:
For the power coating profile with its designation as 6063, state T5, section code 421001, cut length 6,000 mm, color 3003, coating property Grade I, coating code GU40, it shall marked as:
Powder coating profile GB/T 5237.4-6063T5-421001×6000 Color 3003 Grade I GU40
4.2 Quality assurance
4.2.1 Process
See A.1 for process guarantee.
4.2.2 Raw materials
See A.2 for the quality of substrate, pretreatment reagent and powder coating.
4.3 Chemical composition
Chemical composition shall meet the requirements of GB/T 5237.1.
4.4 Mechanical properties
Mechanical properties shall meet the requirements of GB/T 5237.1.
4.5 Size deviation
The size deviation of de-coated profile shall meet those specified in GB/T 5237.1. The assembly and use of the profiles shall not be affected if there are dimensional changes caused by coatings.
4.6 Coating properties
4.6.1 Coating thickness
4.6.1.1 The local thickness of the coating on the exposed surfaces shall not be less than 40 μm, and the average coating thickness shall be controlled at 60 μ m ~ 120 μ m. Due to the complexity of the cross-sectional shape of the profile, it is allowed that the coating thickness of some surfaces (such as inner corners and grooves) of the profile is lower than the specified value. If there are other special requirements for thickness, the supplier and the demander shall negotiate and indicate them in the order (or contract).
Note: The flexibility of the coating will be reduced if the average thickness is too high.
4.6.1.2 If there is a coating thickness requirement for the non-exposed surfaces, it shall be agreed by the supplier and the demander and then indicated in the order (or contract).
4.6.2.3 Gloss
The gloss values and permissible deviations shall meet the requirements of Table 4.
Table 4 Gloss values and permissible deviations Unit: gloss
Gloss value range Permissible deviation
3～30 ±5
31～70 ±7
71～100 ±10
4.6.3 Color difference
The color of the coating shall be basically the same as the pattern agreed by the supplier and the demander. If measured by instrumental method, the color difference ΔEab* between monochromatic coating and the sample is ≤ 1.5, and the color difference ΔEab* between profiles of the same batch (referring to delivery batch) is ≤ 1.5.
4.6.4 Indentation hardness
According to indentation hardness test, the indentation resistance of the coating shall not be less than 80.
4.6.5 Adherence
The dry adherence, wet adherence and boiling water adherence of the coating shall reach Grade 0.
4.6.6 Boiling water resistance
After the high-pressure water immersion test, the surface of the coating shall be free from peeling and wrinkling, but visible and extremely dispersed tiny bubbles are allowed, and the adherence shall reach Grade 0.
4.6.7 Impact resistance
4.6.7.1 After the impact test, the tested plate coating with Grade I property shall be free from cracking or falling off.
4.6.7.2 The tested plate coating with Grade II and III property is allowed to have slight cracking after impact test, but when adhesive tape with adhesive force greater than 10 N/25 mm is used for further inspection, there shall be no sticking phenomenon on the surface of the coating.
Note: The coating pretreated by anodic oxidation is not suitable for impact resistance.
4.6.8 Cupping resistance
4.6.8.1 After the cupping resistance test, there shall be no cracking or falling off of the tested plate coating with Grade I property;
4.6.8.2 Slight cracking is allowed in the tested plate coating of Grade II or III coating properties after cupping resistance test, but there shall be no sticking on the surface of the coating when adhesive tape with adhesive force greater than 10 N/25 mm is used for further inspection.
Note: The power coating pretreated by anodic oxidation is not suitable for cupping resistance test.
4.6.9 Bending resistance
4.6.9.1 After bending test, the tested plate coating of Grade I properties shall be free from cracking or falling off;
4.6.9.2 After bending test, the tested plate coating with Grade II or III properties is allowed to have slight cracking, but when adhesive tape with adhesive force greater than 10 N/25 mm is used for further inspection, there shall be no sticking on the coating surface.
Note: The power coating pretreated by anodic oxidation is not suitable for bending resistance test.
Foreword iii
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
5 Test methods
6 Inspection rules
7 Marking, packaging, transportation, storage and quality certificate
8 Order(or contract) content
Annex A (Informative) Quality assurance
Bibliography
