Standard Memberanthony-wohali
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I would suggest metallographic cross-sectioning to verify crack presence and depth, and then acid etch the metallographic mount as well as remnants of the destroyed part to see if grinder burn/cracking occurred. First suspicion would be grinder check, which can be caused by poorly-controlled machining process.
I do not have the code to hand, however from memory your option 2 is the correct one.
I would not bet any money on it though before I read the code again.
For example i know ‘slags’ is result from MMA welding process…!
I want to learn only for 1) SMAW – Shielded Metal Arc Welding ( MMA ) and GMAW – Gas Metal Arc Welding ( MIG/MAG ) and GTAW – Gas Tungsten Arc Welding ( TIG ) for EVS-EN ISO 10675-1: 2016100% visual inspection is required. No NDE is required unless specified by contract documents
Porosity and weld spatter detected by visual examination should be removed by grinding etc.
It depends on the shape of the reflector. If it’s large and flat, facing your probe, then you’re likely to see echoes at 20, 40, 60 etc as you suggest.
But if it’s small and/or irregular, you may not get a second echo from it directly.
You should follow the codes and use several pair of probes and multi-channel unit
The thickness of the material to be divided in several regions and the time base (delay and range) to be calibrated accordinglyHi,
Yes it is possible, but most of the time the result depends to the defect depth.
Is there more information about the depth or structure ?
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Remote visual inspection (RVI) is a non-destructive testing (NDT) technique for visual observation of a component or region under test where the inspector or technician operates the test equipment from elsewhere
This is covered by 341.3.3
“Discontinuities detected outside the area required to be examined during weld joint examinations should be evaluated and resolved in a manner acceptable to the owner and designer.”
How you practically implement this can be challenging.ASTM E746-18 provides a method of comparing the performance of two (or more) radiographic testing systems. For example, you may wish to compare two manufacturer’s films of nominally the same class, or compare the results of changing the developer chemistry.
By assessing the Equivalent Penetrameter Sensitivity at 50% Probability of Detection, the systems can be compared. For CR, IP plates could be compared; for DDAs the effect of changing the scintillator could be compared.
The best way of learning how to use the RIQIs and ASTM E746 is to practice and see the results. The importance of the specification and RIQI will depend on the reason for the comparisonWho can tell me where can i find more document about ndt conference?
The base metal is for category B weld is SA 333 GR 6 Material wall thk is 8.74 S160
and for category D weld shell base metal is SA516 gr 70 and its thickness is 22mm.
Is there a reference in the code for RT not required for non butt weld for category D weld.
ThanksThe width of the the negative HV pulse is determined by the time constant of the series capacitor and the load resistance, provided that the width of the ON drive to the MOSFET is long enough. Otherwise, not all the energy in the capacitor is delivered to the load.
The time constant of the capacitor and the resistor from MOSFET drain to the ~300Vdc determines the recharge time and therefore the maximum PRF.
For an cheap HV supply without winding a special transformer, I’d TRY a small transformer (say) 240V mains to 12-0-12V (24V centretapped) then use a couple of power transistors to turn it into an oscillator. From a bridge rectifier and smoothing on the 240V winding, which is now NOT connected to mains but acts as an output, I’d expect to get the 300Vdc (the actual voltage would depend on the DC input voltage to the drive transistors).
TAKE CARE, EVEN THOUGH IT COMES FROM A LOW DC VOLTAGE SOURCE, YOU COULD STILL GET A NASTY SHOCK.
You may also find HV sources on the internet (for flash tubes???)
Hi,
You can refer to ASME SEC I – Non mandatory appendix-B.
Clause B-8 of this appendix specifies this acceptanceIt depends on the diameter and the wall thickness of the pipeline. You have to consider the time for the band/scanner positioning. Then the scanning time and the interpretation time. For most of the commonly used AUT systems, the scanning speed is in the range 30 to 80 mm/sec. Based on that, you can try to calculate the scanning time for your scope of work. On top of that, you have to consider the time for the calibrations (depending on the specification/procedure, it can be every weld or every 5 welds or every 10 welds, etc.). Interpretation time is a “random” variable. A clean strip chart requires relatively “no time” to be assessed. “Dirty” welds will require much more time.
The crew depends again on the diameter of the pipeline. If it is a large OD pipe for that type of production rate, I would say that you need at least 2 AUT operator (or 1 operator and 1 supervisor) and probably 3x scanner technicians (2 working on the “scanned” weld and the third one that can clean the following weld/cooling it if needed/setup the band/etc). 100 welds on a 10 hours shift means one weld every 6 min. It looks to me a really challenging target for one spread (for both welding and AUT). However, AUT would be faster than RT done with crawlers.
A complete backup for the AUT system on site I would say that is “mandatory”.in case of glass fiber reinforced plastic (GFRP) pipes you should also think about microwave testing instead of ultrasonic testing.
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If the existing cathodic protection system is adequate, it should easily protect the portion of pipeline in the water as water is less resistive than soil. However, you might consider installing a permanent reference electrode in this location for occasional measurement.
I believe however that the biggest risk will likely be possible crevice corrosion at the tape to paint interface.
A very diligent visual inspection procedure should be established to insure the exterior of the pipeline remains corrosion free.radio-chemistry, an interesting topic and what got me interested in NDT 35 years ago. But the isotope you refer to is not one usually associated with NDT!
Some background for those not familiar;
Bromine has 2 stable isotopes, Br79 and Br81.
Br80 is one of several unstable isotopes of Bromine.
Also, Bromine 80 is a nuclear isomer. A nuclear isomer has the same nuclear mass and same atomic number but different radioactive properties. In this case the isomers are 35Br80 and 35Br80m (where 35 is the Z number or atomic number and 80 the atomic mass and 35 would be a subscript and 80 and the letter m are superscript).Wikipedia describes nuclear isomers as “…a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons. A nuclear isomer occupies a higher energy state than the corresponding non-excited nucleus, called the ground state. Eventually, the nuclear isomer will release the extra energy and decay into the ground state,…”,.
In my old school text “Radio and Nuclear Chemistry” by Friedlander Kennedy and Miller (Wiley 1964) they note that the unstable isotope of Br80 decays by several decay methods including Beta negative with associated gamma emission, Beta positive (positron), and Electron Capture, and it has a short half-life of only 17.6 minutes.
Bromine 80m on the other hand has a half-life of 4.5 hours making it “metastable”. It decays by “Isomeric Transition (IT) via internal-coversion electrons.Since my reference was quite old I decided to check other locations available online and confirmed that the 80m mode was indeed the metastable version and did not decay by beta negative or beta positive modes. Instead it is the less stable version with a 17.6minute half-life that decays with the beta negative or beta positive modes.
You asked WHY Bromine80 decays with 2 options; i.e. both beta negative and positron (beta positive). Generally it is considered that beta negative decay dominates on the neutron excess side of the mass-parabola and positron decay on the proton rich side of the stable isobar. The actual route of decay is related to a variety of selection rules in quantum mechanics. There are “allowed” and forbidden” transitions to de-excite to a more stable state. However, “forbidden” does not mean it is in fact not allowed, but instead exists with only a low probability.
Details of the classroom lectures on quantum mechanics describing the transitions are now too long ago in my past. I suggest you get a copy of Friedlander or some similar text to fill in the details (they are not trivial).I guess you will find here not much colleagues in touch with “NDT” in biology. E.g. my main contact in this field was Laser-Ultrasonic as used in Medicine and Biotechnology just because it was surprising for me that such a “high energy excitation is possible with organic (living) material – I had done projects with this only on metallics and CFRP….
My best information I got in this field via Researchgate.net. This is something like Linked-in for researchers. Best: it is free to access, you have only to register, and you find either papers free to download or you can ask researchers to provide copies. and you have the chance to ask questions into the community. Try this.
Lot of researchers use FLIR-Thermocameras (of course you find also other brands) Checkout with those companies, how they sell their systems in your field of applications. Usually the application engineers know about the researchfields their cameras are used for.Mt on bevels is an examination that you will do thousands of times and not find anything but once in a while you may find a lamination os segregation that will prevent welding being carried out. This is the main reason for the bevel examination.
MT shoud be carried out after all mechanical work has been completed and some argue that if you use white contrast paint the welders will then grind the paint off so that is a further mechanical work….. etc. Some manufacturers of MT chemicals also supply paint remover in a spray can. The fluorescent method is an alternative but requires darkness. Most norms don’t say that you must use a contrast paint but only if the background doesn’t give sufficient contrast.
Yes PT is a good alternative, the main disadvantage is cost (time). A proper PT examination, even on one bevel, will take you at least 30 minutes (depending on the norm) whereas MT is usually completed in a few minutes.I have just gone through such a debate. My orginal rationale indicated that MFL was a branch of MPI. This method looked almost the same as MPI with the particles being replaced by sensors.
Looking at it from the sensors however, the technology looks similar to ECT.
We had the same problem with the Barkhausen effect.
When used with magnetic sensors the magnetic Barkhausen effect is lumped with MT (or should it be ET because of the sensors??).
When used with acoustic sensors the “elastic waves” are monitored so is it an acoustic method (UT)??
It would seem to be a debate based on on if we categorise by transmit or receive.
MFL and MT use similar methods of inducing a field but ET and MFL use similar detectors (when using coils).
Is there an existing agreement on how this is to be handled or will we continue to have different groups grouping in different ways?I WILL SEND YOU ALL INFORAMTION LATER Thankyou
