GB/T 11373-2017 in English

Surface pretreatment methods

GB/T 11373-2017 specifies a variety of surface pretreatment methods, including:

• Degreasing: Use water-based detergent or organic solvent to clean, avoid chlorofluorocarbons.
• Sandblasting: Use metal or non-metal abrasives to ensure surface cleanliness reaches Sa3 level.
• Threading/grooving: Necessary treatment for spraying wear-resistant layer on internal surface.
• Reverse polarity transferred arc cleaning: Suitable for oxide layer removal in vacuum plasma spraying.

Sandblasting technical details

Sandblasting is a key step in thermal spray surface pretreatment. The following are key parameters and technical requirements:

• Abrasive selection: According to ISO 12944-4 and ISO 11126-7, angular sandblasting abrasives are preferred.
• Roughness control: Use the measurement methods specified in the GB/T13288 series of standards (comparison sample method, microscope focusing method, etc.).
• Post-pretreatment cleaning: The residue on the sandblasted surface must be completely removed to avoid affecting the bonding strength of the coating.

Comparison with ISO 12944-4

GB/T 11373—2017 is similar to ISO 12944-4 in surface treatment requirements, but pays more attention to the special needs of thermal spraying processes. For example:

• GB/T 11373 has clear requirements for the selection and fragmentation rate of sandblasting abrasives.
• ISO 12944-4 mainly focuses on the surface treatment of anti-corrosion coating systems for steel structures.

Comparison with EN 13507

GB/T 11373—2017 is consistent with EN 13507 (Surface Preparation for Thermal Spraying) in some technical details, but the specific requirements are different:

• GB/T 11373 has detailed provisions on the use of bonding substrates.
• EN 13507 focuses more on coating performance evaluation.

Operational step recommendations

1. Choose a suitable surface preparation method according to the purpose of the workpiece.
2. Ensure that the blasting abrasive meets the requirements of ISO standards, and give priority to abrasives with high hardness and sharp shapes.
3. Strictly control the blasting parameters, including blasting time, distance and angle.
4. Spray immediately after pretreatment to avoid surface contamination.

Health and Safety Precautions

During surface pretreatment, special attention should be paid to:

• Use cleaning agents that meet environmental protection requirements.
• Ensure that the sandblasting equipment has a dust collection and filtration system.
• Operators wear appropriate protective equipment (masks, goggles, etc.).