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DPCNews 068 - NDE,NDT and NDI | Automatic processes for discontinuities indication reading and part-acceptance/rejection | An unfortunate misunderstanding

Written by Dubosc
Saturday, 27 September 2014 15:05

In the front page this month | September - October - November 2014

[EDITO] Nondestructive Examination, Nondestructive Testing & Nondestructive Inspection.

[NEWS] Automatic processes for discontinuities indication reading and part-acceptance/rejection.

[OLDIES BUT GOODIES] An unfortunate misunderstanding




Nondestructive Examination, Nondestructive Testing & Nondestructive Inspection.

What is the difference between Nondestructive Examination and Nondestructive Inspection? One of us asked a Member of the French Confederation for Non-Destructive Testing (COFREND), a specialist in terminology.

>> Read his answer



Automatic processes for discontinuities indication reading and part-acceptance / rejection.

In the early ‘70s, many PT specialists came to the conclusion that the only way to improve significantly the reproducibility and the reliability of the fluorescent penetrant inspection would be not to use human eyes, subject to unavoidable variations, but to use instead a system detecting fluorescent indications with a high level of confidence.

As a general matter, at least 60 to 70 % of the parts that an inspector checks would not need to be inspected, with a risk that, as his watchfulness decreases, he could not detect defective parts, a reaction somewhat similar to a driver who falls asleep while driving for too long on a straight main road. Using “ghost parts,” as in the car industry, does not prevent such a failure.

>> Read more



An unfortunate misunderstanding.

Aircraft wheels comprise two flanges held together by bolts, a bolt being a combination of a screw + a nut. These screws price explains why they are checked before reuse, while nuts are always thrown away for safety concern.

The inspection aim is to detect incipient cracks which start in a direction perpendicular to the highest tensile stress. They may appear in the fillet, at the toe-weld, at the thread top or bottom.

A broken bolt leads to some wheel wearing. Further broken bolts and/or nuts are a kind of bullets more or less locked inside the wheel. These bolts being made of ultra high-tensile steels, MT was considered as the method of choice.

Till the day when...the story took another way!

>> Read more


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Last Updated ( Tuesday, 25 November 2014 14:03 )