DPCNews 042 - Calibration/verification / MT magnetizing techniques / Revamping of a colour contrast penetrant / Mail inbox

DPCNews

Written by Administrator

Saturday, 10 December 2011 16:19

January 2012

Best Wishes
for a Happy New Year

2012: Priority to the quality of services and products

Many people, the world over, complain about a diminishing quality of services and products, be they consumer goods or technical equipment.

Thus, in 2012, priority shall be given to the quality of products and services.
In no way, the international competition can be pursued at the expense of quality, when, sometimes, strong temptations and pressures may exist to validate non-compliant results of tests. Such a situation may expose anyone to risks when using the products/equipment.

Indeed, we cannot accept such risks. Planes, ships, refineries, even without talking about nuclear plants, shall be inspected by reliable people, able to take unusual decisions, sometimes out of any recognized standard, but with full knowledge of the evidence just to be sure there is no hidden discontinuity, just to be sure the equipment can be safely put in service.

Our website is there to help you ask the right question, to know when it is a good idea to be dubious about a result because you "feel" there is something that is outside of what you have ever met or seen.

Our website has already brought many readers answers to questions. It has helped them to understand where a specific problem could come from. Further, when the answer is not in our papers, scores of readers took the opportunity to ask us what we would do in this or that situation, what could be the explanation for a failed inspection. Quite often, these questions become papers, as you will see again and again, as even a failed inspection may be a valuable lesson for others.

We will continue our "Oldies but Goodies" section, which many readers are enthused by. Though they have a flavour of old times, these "short stories," always a reliable report, make readers think of similar problems they have already met in their job, or understand that something very similar could happen: a good way to prevent troubles!

Once again, we think that the quality in NDT, in the relationship between primes and subcontractors or service companies, a good understanding by auditors of the methods and processes, a well-placed humility, i.e. the ability to recognize that one does not know everything even in methods wrongly called "simple" by misunderstanding or a lack of knowledge, methods as "basic" as Penetrant Testing and Magnetic Particle Testing, are the main points for delivering good, reliable, safe parts.

In fact, everyone travels by train, by plane, by car; every one may use a roller-coaster with his children. Better that all this equipment is in good condition, having been manufactured and controlled the right way, with the right materials and equipment, by well-trained and conscientious people.

Underneath, find the list of the new papers that you can read this month on our Website:

In the "Edito" section

Calibration/Verification a new survey?

This paper is a follow-up of our DPCNewsletter N°029 titled Quality of some calibration services, published on our Website in October 2010.

In the "NEWS" section

MT magnetizing techniques

We have the pleasure to publish on our Website a contribution by a French MT expert, Stéphane GRAVELEAU, from the R and D Department of SREM TECHNOLOGIES (France).
Magnetizing techniques and current waveforms are described.
Very often, the wave forms displayed in training courses, even in standards, are those got on weakly inductive loads. As this paper explains, on highly inductive loads, the curves do not have the form that one would expect.
In fact, waveforms are very dependent on the electric characteristics of the load.
So far, this connection is rarely highlighted.
By releasing this document, we think we fill in a gap; furthermore, we hope it will be of some interest for you, and that it will give you a top - quality piece of information.

In the "Oldies but goodies" section

How to rejuvenate a colour contrast penetrant

Unthinkable today: yet, some decades ago, some low-flash-point colour contrast penetrants, used in tanks, evaporated. This evaporation had serious consequences. To remedy this, a manufacturer designed a ‘‘rejuvenating agent’’ called "Solvent Additive for Penetrant".

In the "Mail inbox" section

We answer this month to the following questions:

• Large parts: how to wash a fluorescent penetrant

A reader wrote us: "When washing parts, some time ago, after using a water-washable (WW) Level 3 fluorescent penetrant, I wondered about the washing time.
Imagine I work on very large parts: first, I spray water on the entire surface, to ease its washability. When I spray water for the second time (to wash off the excess of penetrant), is there a risk that the surface-active agents (surfactants) contained in the penetrant make it possible to remove penetrant from discontinuities, leading to an overwash situation? When these surface agents (surfactants) are wet, I think they diffuse in the penetrant, a bit as an emulsifier does. What is your opinion?"

• Tribofinishing before MT inspection

Another of our readers asked us whether part deburring by tribofinishing (also called vibratory finishing) before MT could significantly affect the detection sensitivity of MT inspection.

We, Pierre CHEMIN and Patrick DUBOSC, welcome any comment, any idea. If you have some examples you would like to see discussed here, please give us all the useful indications. If you require confidentially, we would modify locations, names and some parameters to prevent any traceability.
Nevertheless, we are convinced that our site may be a kind of surge-valve: the topic is NOT to target this company, or that auditor; but it is always to make users think, to make them ask themselves, or others, the right questions.

We may also give advice, once again on a confidential basis if needed: please, feel free to ask questions, to document our data basis: about Material Safety Data Sheets (MSDS), about environment, a chemical name you don't understand, a Penetrant process you have heard about, etc.
We have plenty of examples, some being out of all the specifications/standards, which led to the discontinuities detection, when the "current, normal, processes" prevented discontinuity finding.

Last Updated ( Saturday, 10 December 2011 17:58 )