According to relevant standards, the specific requirements for the inner wall coating of carbon steel tanks are as follows:
1. **Coating material requirements**
When carbon steel tanks are used to transport edible oil, their inner wall coating must comply with the requirements of **GB 4806.10 "National Food Safety Standard Food Contact Coatings and Coatings"**. This standard specifies the hygienic requirements for food contact coatings and coatings to ensure that coating materials do not release harmful substances such as lead, cadmium, arsenic, etc. when in long-term contact with edible oil.
2. **Coating performance requirements**
- **Corrosion resistance**: The coating should have good corrosion resistance and be able to resist chemical erosion of edible oil for a long time.
- **Oil resistance**: The coating must be oil-resistant to prevent edible oil from dissolving or damaging the coating.
- **Static conductivity**: The coating should have a static conductivity function to prevent safety risks caused by static electricity accumulation.
- **Coating thickness**: The dry film thickness of the coating should usually not be less than 200 microns. For some special parts (such as the bottom of the tank), the coating thickness should not be less than 300 microns.
3. **Construction and quality requirements**
- **Surface treatment**: Before applying the coating, the inner wall of the tank needs to be sandblasted to achieve a bright metal surface to ensure the adhesion of the coating.
- **Construction specifications**: The coating construction must be carried out in strict accordance with relevant standards, including the coating sequence of primer and topcoat, coating thickness control, etc.
- **Quality inspection**: After the coating construction is completed, quality inspection is required, including coating adhesion, hardness, thickness and other indicators to ensure that the coating quality meets the requirements.
4. **Cleaning and maintenance requirements**
- **Cleaning standards**: After each use, the tank body needs to be thoroughly cleaned to ensure that there is no residual oil and contaminants.
- **Maintenance cycle**: The integrity of the coating needs to be checked regularly, and scratches or damaged parts of the coating need to be repaired in time to prevent corrosion.
The above measures can ensure the safety and hygiene of carbon steel tanks when transporting edible oil, while extending the service life of the tank body.