JB/T 5000.12-2007 in English

1 Scope
This Part of JB/T 5000 specifies the paint techniques and inspection requirements for heavy mechanical products and their spare parts.
This Part is mainly applicable to the surface paint of iron and steel products. Without special requirements in the contract documents, the surface paint of the products shall be in accordance with the requirements of this Part.
2 Normative References
The following standards contain provisions which, through reference in this part of JB /T 5000, constitute provisions of this part. For dated references, all subsequent modification or revision (excluding correction contents) are not applicable to this Part. However, all concerned Parties are encouraged to study if the latest editions of these documents can be applied. For undated references, the latest editions of the normative documents are applicable to this part.
GB/T 2893 Safety colors (GB/T 2893—2001, neq ISO 3864: 1984)
GB/T 5206.1 Paints and varnishes; Vocabulary; Part 1: General terms (GB/T 5206.1—1985, eqv 4618-1: 1978)
GB/T 5206.4 Paints and varnishes; Vocabulary; Part 4: Terminology relating to physical and chemical properties of coatings and films GB/T 5206.4—1989, neq ISO 4618-1: 1984)
GB/T 5206.5 Paints and varnishes; Vocabulary; Part 5: Terminology relating to defects of coatings and films (GB/T 5206.5—1991, neq ISO 4618-2: 1984)
GB/T 6514 Safety code for painting - Safety, ventilation and air clean-up for painting process (GB 6514—1995, neq NFPA 33: 1989)
GB/T 7231 Basic identification colors and code indications and safety sign for industrial pipelines
GB/T 7692 Safety code for painting - Safety, ventilation and air clean-up for pretreatment process of painting
GB/T 8264 Glossary of painting terms
GB/T 8923 Rust Grades and Preparation Grades of Steel Surfaces before Application of Paints and Related Products (GB/T 8923—1988, eqv ISO 8501-1: 1988)
GB/T 9286 Paints and varnishes - cross cut test for films (GB/T 986—1998, eqv ISO 2481: 1992)
SY/T 0407 Specification of steel surface preparation before application of paint
GSB 05-1426 Color standard cards for films
ISO 12944-2 Paints and varnishes - corrosion protection of steel structures by protective paint systems Part 2: Environment classification
ISO 12944-5 Paints and varnishes - corrosion protection of steel structures by protective paint systems Part 5: protective paint systems
3 Terms and Definitions
Terms and definitions in GB/T 5206.1, GB/T 5206.4, GB/T 5206.5 and GB/T 8264 are applicable to this Part.
4 Technical Requirements
4.1 Surface Treatment before Painting
As for all iron and steel materials used for equipment manufacture, surface derusting treatment shall be carried out before painting.
As for all iron and steel material or workpiece surface required to be painted, rust, oxide skin, grease, dust, earth, salt and dirt must be cleared before painting.
4.1.1 Before derusting, the grease and dirt on the surface of iron and steel shall be eliminated with organic solvent, alkaline solution, emulsifier, and steam, etc.
4.1.2 See Table 1 for the method, grade and application scope of derusting on the surface of iron and steel. Derusting requirements and evaluation methods for each grade of Sa and St in Table 1 shall be in accordance with the requirements of GB/T 8923.
See Annex A for acid cleaning method and treatment requirements.
4.1.3 As for the weldment that need heat treatment after assembling and welding, the derusting procedure shall be carried out after heat treatment.

Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Technical Requirements
4.1 Surface Treatment before Painting
4.2 Design of Anti-Corrosion Coating of Mechanical Products
4.3 The Paint Requirements for the Special Positions of Mechanical Products
4.4 Painting Color Requirements
4.5 Paint Construction Requirements
5 Paint Quality Control and Inspection
6 The Resistance Evaluation of Coating Separating From the Substrate
Annex A (Normative) Acid Cleaning
A.1 Application Scope and Quality Requirement
A.2 Surface Treatment before Acid Cleaning
A.3 Acid Cleaning Methods and Requirements
A.4 Safety Measures
Annex B (Normative) Coating Durability
Annex C (Normative) Classification of Film Cross Cut Test Results