Dye Penetrant Inspection
Dye Penetrant Inspection (DPI) is used for detecting surface breaking defects such as cracking in both ferrous as well as non-ferrous materials. However for ferrous materials Magnetic Particle Inspection is recommended due to its sub surface ability.
We often use dye penetrant for weld inspections, as well as on assets where there is suspected cracking such as columns, plates, attachments.
Suface Finish & Preparation
Dye Penetrant requires a clean bare metal finish for correct inspection. We recommend cleaning of welds to SA 2 ½ to a near white metal finish. This is defined as:
Near-White Blast Cleaning – Removal of nearly all mill scale, rust, rust scale, paint, or foreign matter by the use of abrasives propelled through nozzles or by centrifugal wheels, to the degree hereafter specified. A Near-White Blast Cleaned Surface Finish is defined as one from which all oil, grease, dirt, mill scale, rust, corrosion products, oxides, paint or other foreign matter have been completely removed from the surface except for very light shadows, very slight streaks or slight discolorations caused by rust stain, mill scale oxides, or light, tight residues of paint or coating that may remain. At least 95 percent of each square inch of surface area shall be free of all visible residues, and the remainder shall be limited to the light discoloration mentioned above.
To find out more about how we can help with your next inspection project call us on 01469 541586. Or send us an Email.