GB/T 12754-2019Prepainted steel sheet and strip (English PDF)

1 Scope

GB/T 12754-2019 is the Chinese national standard on prepainted steel sheet and strip, in the field of metallurgy. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 25 March 2019 by the State Administration for Market Regulation; Standardization Administration of China, and has been in force since 1 February 2020. Classification: ICS 77.140.50, CCS H46. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This Standard specifies terms and definitions, grade representation method, classification and code, order content, dimensions, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificates of pre-painted steel sheets and strips. This Standard applies to pre-painted steel sheets and strips for building interior and exterior applications (hereinafter referred to as pre-painted steel sheets). Pre-painted steel sheets for home appliances and other purposes may also refer to this Standard.

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 247 General rule of package, mark and certification for steel plates (sheets) and strips

GB/T 1766-2008 Paints and varnishes - Rating schemes of degradation of coats

GB/T 8170 Rules of rounding off for numerical values & expression and judgement of limiting values

GB/T 13448 Test methods for pre-painted steel sheet

GB/T 17505 Steel and steel products - General technical delivery requirements

3 Terms and definitions

For the purpose of this document, the following terms and definitions apply.

3.1 pre-painted steel sheet Product obtained by continuously applying an organic painting on a surface- pretreated steel substrate and then baking and curing.

3.2 steel substrate Steel strip used to apply painting.

3.3 top side A side with higher requirements for color, coating properties, surface quality, etc. on both sides of pre-painted steel sheets.

3.4 bottom side The other side that is opposite to the top side of pre-painted steel sheets.

3.5 building exterior applications Applications that are affected by the external atmospheric environment.

3.6 building interior applications Applications that are affected by the internal atmosphere.

4 Grade representation method, classification and

4.1 Grade representation method The grade of pre-painted steel sheets consists of the uppercase English letter T plus the grade of steel substrate.

5 Ordering content

5.1 Contracts or orders ordered in accordance with this Standard shall include the following.

5.2 If the dimensional and flatness precision is not indicated in the order contract, the supply party shall supply the product according to the normal precision.

6 Dimensions, shape, weight

6.1 The nominal dimension range of pre-painted steel sheets is shown in Table

2.The nominal thickness of pre-painted steel sheets is the nominal thickness of the steel substrate before pre-painting, excluding the coating thickness.

6.2 The tolerance of width, length, shape and steel substrate thickness of pre- painted steel sheets shall comply with the requirements of the corresponding steel substrate standards.

6.3 Pre-painted steel sheets are delivered according to actual weight.

8 Test methods

The test methods for each batch of pre-painted steel sheets shall comply with the requirements of Table 8.

9 Inspection rules

9.1 The inspection and acceptance of pre-painted steel sheets shall be carried out by the supply party's inspection department.

9.2 Pre-painted steel sheets shall be inspected in batches. Each batch shall consist of pre-painted steel sheets of not more than 30 t, with the same grade, the same specification, the same coating weight, and the same coating surface condition, topcoat type, topcoat function, coating structure and color.

9.4 The sampling quantity and sampling position of pre-painted steel sheets shall comply with the requirements of Table 8.

9.5 The re-inspection and determination rules of pre-painted steel sheets shall comply with the provisions of GB/T 17505.

10 Packaging, marking and quality certificate

The packaging, marking and quality certificate of pre-painted steel sheets shall comply with the provisions of GB/T 247.In addition, the marking shall also include the contents such as plating weight of steel substrate, topcoat type and color.