The specific steps for using dye penetrant inspection (DPI) on flanges:
✅ Preparation
✔ Clean the Surface:
Ensure the flange surface is clean and free from contaminants like grease, oil, dirt, or rust. Use a suitable cleaner or solvent to remove any residues.
For best results, the surface should be dry before proceeding.
✔ Inspect the Surface:
Visually inspect the flange for any obvious defects or damage before applying the dye penetrant.
✅ Application
✔ Apply the Penetrant:
Spray or brush the dye penetrant onto the flange surface, ensuring complete coverage. The penetrant should be allowed to seep into any surface cracks or defects.
Follow the manufacturer’s instructions regarding the thickness and application time. Generally, the penetrant should remain on the surface for about 5-30 minutes, depending on the type used and the manufacturer’s recommendations.
✔ Remove Excess Penetrant:
After the dwell time, remove excess penetrant using a clean cloth or a water rinse (if using a water-washable penetrant). Ensure not to remove the penetrant from within the cracks.
✅ Application of Developer
✔ Apply the Developer:
Apply the developer over the surface. The developer acts as a blotter, drawing the penetrant out of the cracks and making it visible.
The developer can be in the form of a powder, liquid, or aerosol. Follow the instructions for application and drying time.
✅ Inspection
✔ Inspect for Indications:
After allowing the developer to dry, inspect the surface under suitable lighting conditions. A white light or ultraviolet light (for fluorescent penetrants) is commonly used.
Look for indications of dye that have seeped out of cracks or defects. These indications will appear as contrasting marks against the background.
✅ Final Steps
✔ Document Findings:
Record any defects or indications found during the inspection. Note their locations and characteristics for further evaluation or repair.
✔ Clean the Surface:
After inspection, clean the surface to remove any residual penetrant and developer, especially if the flange will be put into service.
✔ Evaluate Results:
Determine if the indications found are within acceptable limits or if further investigation or repair is required.
