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Crack Diagnosis Of Aluminum Parts General Information - Ah60.00-P-0014-01N

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It is necessary to check whether any cracks, inclusions or other weld faults are present before and after performing repair work on aluminum components.

A suitable method of testing is the simple dye penetration test, which accentuates faults starting at the surface or in immediate connection with it which cannot be seen with the naked eye, through color contrast. This method utilizes the capillary effect of fine surface openings. Liquids containing dyes with low surface tension penetrate into these openings and can be verified there with suitable contrasting agents.

Usually luminous red or yellow-green fluorescent dyes are used a penetration agents, which can be washed off with water. The penetration agent can be sprayed on or applied with a brush.

During the penetration time, the penetration agent should never be allowed to dry out. The smaller the surface faults, the longer the penetration time (approx. 5 to 30 minutes).

The developer used subsequently requires a high absorption capacity, to suck the penetration agent out of the damaged spot. This makes the fault visible by contrast in the developer layer. The development time is analog to the penetration time. As a matter of principle, however, faults can only be verified on the material surface.

Always observe the specific Safety instructions of the individual manufacturers before using the cleaner, contrast agent, and developer.

All three diagnostic agents are highly inflammable. The contrast agent also poses a health hazard.

Detection process: 

G16050933Courtesy of MERCEDES-BENZ USA

Typical damage indications with dye penetration method 

G16050934Courtesy of MERCEDES-BENZ USA