miércoles, 25 de diciembre de 2013

ASNT NDT LEVEL III BASIC and UT METHOD Examinations

PART 1 BASIC

The Basic examinations  looks simple. In my experience, close to 80% of questions comes from ASNT SNT TC 1A, CP 189 and MATERIALS and PROCESS BOOK from ASNT.

I recommend the following lectures:
  • ASNT LEVEL II Basic Study Guides in all published methods
  • HANDBOOK OVERVIEW.
  • ASNT SNT TC 1A (2011)
  • CP 189 (2011)
  • ASNT MATERIALS AND PROCESS book
  • ASNT Questions and Answers books up to level II.

The best method to study is to be critic, make your own questions. The questions are not difficult by itself, ASNT ask for comprehension instead memory. The exam is a professional object, the people who makes the exam really want to explore the knowledge as a whole. There are an important number of questions with more than one correct answer, you shall select the best option. This type of questions reflect the depth of your knowledge.

One important technique is to read in ACTIVE MODE, this means that you will write a list of questions before read a topic, for example:

Which is the principle of the method, the main physics concept?
Which inspection needs could resolve the method.
How often is used the method.?
Which conditions are required to apply the method?
How many techniques have the method and how this techniques works?
Instrumentation related with the method.?
Etc etc etc… This is the best way to read without be bored… and active lecture is the best way to learn by reading.

After the first lecture has been concluded, some of the questions should be answered, but many other question rises from this first critical reading. So, make new questions and read again. A very good approach is to read 3 times the same topic in a critical way. Make a list of questions, short resumes and tables... comparisons are very important to stimulate the memory associations.

ULTRASONIC METHOD

I recommend the following books

  • UT ASNT LEVEL III STUDY GUIDE
  • Four first chapters from KRAUTKRAMER AND KRAUTKRAMER (Last edition)
  • UT ASNT HANDBOOK
  • Question and Answer book Level I, II and III questions
If you have an score with more than 80% in the Study Guide and in the Question and Answer book Level I, II and III questions you can be sure you will have a good score in the real life examination.

It is not practical to ask which question someone could remember direct from the examination, the questions are the same in nature from the Study Guide and Question and Answers book.

VERY IMPORTANT LEFT THE PROCEDURE QUESTIONS FOR THE END !!!! The method examination is accompanied with a procedure and a list of questions related with the procedure, left this aspect of the examination to the end. 

Do not spent time with the booklet of equations...  it is only in case of  emergency.


IMPORTANT ADDITIONAL 

1) Carlos Guinand, an experimented ASNT NDT Level III in many methods gave me a recommendation that is very useful during the examination. Make a list with the number of your doubtfully questions. Ex. During the examination, if you have a doubt about the question # 41, write the number of this question (41) in separate list in a separate page. At the end of the examination, you will look for this questions to verify the answer.  This will help you save very valuable minutes.

2) Avoid to spent time with the booklet of formulas that is supplied with the examinations, this could scare you since it have many page of equations, and there is a high probability that this book will not be needed.

3) Consider using methods for answer multiple choice questions even ASNT usually minimize effects that help to select the right answer without knowledge (http://www.studygs.net/tsttak3.htm).

4) To have an overview of your results you can apply the following rule of thumb method:
A) You will fail close to the 10% of questions that you are absolutely sure you are right
B)  You will fail close to the 50% of questions that you have doubts about the right answer.
C) You will fail close to the 80% of questions which you do not have any idea about rigth answer.

5) Day before exam take a long walk, this day make soft physical exercises spent calories to be relaxed at night, not recommended to take much coffee since it is important to sleep.

6) The following post from OLDANI OLIVIERO runs (ndt.net forum):

Re: ASNT LEVEL III BÁSIC QUESTIONS

In Reply to jose albanela on 19:34 Aug-29-2012 (Opening).
You can take the Basic ASNT Guide. There are 480 questions to be used as reference. Those questions are of the same difficulty of those used for the examination. Only few questions included into the Guide could be part of the examination. Test by yourself. On 480 questions a score of 80% could give you the needed confidence to be adequately prepared.

Never loose the control, some questions could be difficult do not spent time with... 

DO NOT FORGET TO COMPLETE THE ANSWER QUESTION SHEET. Some persons begin to complete the small balls answer sheet just some minutes after the end of the test... 



sábado, 23 de noviembre de 2013

Schoch Shift Effect

The Schoch Shift Effect is a very interesting and non intuitive effect. a compression wave who travel in a liquid and strike an elastic solid close to the second critical angle, seems to split in an specular and non specular reflected lobes with the presence of a null zone (as shown bellow).




Schlieren photograph taken by Neubauer and Dragonette:

W. G. Neubauer and L. R. Dragonette, “Measurement of Rayleigh
phase velocity and estimates of shear speed by Schlieren visualization,”
J. Appl. Phys., vol. 45, no. 2, pp. 618–622, 1974.

viernes, 1 de noviembre de 2013

Lack of Fusion Wagon Tracks

A couple of ¨parallel¨ indications lines bounding  the root bead, are classically called ¨wagon tracks¨ by skilled radiographers.This indication is explained by RT personnel as a couple of almost parallel slag inclusion lines after the root pass has been completed. Sometimes this phenomenon involves a couple of lack of fusion lines side by side as can be seen in the image below:


From one side, the UTPA indication is shown below:


jueves, 31 de octubre de 2013

combined defects

Sometimes, defects don´t come alone. Post Destructive examination on Ultrasonic detected indications reveals that combination of defects is not rare. Image below show a slag + lack of fusion. (segments of slag where non intentionally extracted during preparation).


Lack of Fusion Detection

Lack of fusion is one of the most detected discontinuity by UT pulse echo method, conventional or Phased Array mode. Sometimes welders ask that during repair this was not possible to ¨see¨ any discontinuity during grinding or gouging. It is important to take in mind that lack of fusion could be extremely tight and is not possible to detect by non controlled destructive methods.
In the image a extremely small lack of fusion in an austenitic steel weld, that could not be seen without a carefully destructive examination.


Curriculum Vitae

Carlos Correia. Materials Engeeniering Degree (Venezuela Universidad Simón Bolívar  -  1995). Welding Engeeniering Studies (France Institut de Soudure 1998). MASTERS DEGREE PHYSICS OF NON DESTRUCTIVE TESTING (Venezuela – Universidad Central de Venezuela – 2009).
Relevant field experience:
  • SMAW welder
  • Inspector as level II MT, PT, UT, VT, RT, ET. 
  • Extensive use of UT Shear Wave for weld inspection
  • Advanced UT Detection using the so called creeping technique
  • Advanced Sizing using Tip Diffraction and related methods  
  • Extensive use of TOFD for butt weld inspection in pressure vessels
  • Manual UT Phased Array Inspection of butt welds
  • Encoded UT Phased Array Inspection of butt welds
  • UTPA+TOFD
  • Corrosion mapping in tank shells using Rexoform
  • Corrosion mapping in piping systems using Hydroform and raster scanning.
  • Tomoview frequent user.

Research:
  • Statistical analysis of UT signals
  • DSP of ultrasonic signals and images
  • Applying filtering and Neural Networks for Pattern recognition of UT signals
  • TOFD Neural network signals simulator
  • Failure analysis on welded components
  • H2 high temperature UT damage detection (Backscattering and Velocities change).
Instructor of following training programs:
  • Welding Metallurgy (80 hours program)
  • Introduction to Phased Arrays
  • Advanced Phased Arrays for weld inspection
  • TOFD
  • PA+TOFD
  • Corrosion Mapping (Hydroform Chain Scanner)
  • Corrosion Mapping (Rexoform TRIPOD CRAWLER)
Relevant Training received (compilation):
  • Welding Metallurgy and Welding Engineering: Institut de Soudure – France
  • Phased Arrays Basic and Advanced, TOFD and Tomoview I and II: Eclipse Scientific – Canada
  • Transducer construction and modeling with ANSYS – Venezuela
  • MT, PT, RT, UT Level I and II – Venezuela
  • ANSYS WORKBENCH – Venezuela

Relevant Used Software:
  • Omniscan MXU 3.1
  • Tomoview 2.10
  • UT Win Replay
  • Matlab
  • Autocad
  • Ansys
  • Microplus
  • Office package

Languages:
  • Spanish (1st)
  • English
  • French
  • Portuguese

Certifications:
  • ASNT NDT LEVEL III UT # 176992
  • AWS CWI 00110921

Papers at www.ndt.net