Standard Memberanthony-wohali
Standard MemberForum Replies Created
I understand how you feel. I have been a non-specialist for over 50 years but came to this from a different direction. I have a degree in Metallurgical Engineering and was working in a shipyard when the Navy decided technical responsibility for NDT should go to the metallurgical laboratory. The engineering degree has been extremely valuable to me! I have developed NDT techniques for new products and materials using RT, CT, NRT, UT, PAUT, ET, MP, PT, Microwaves, various types of bond testing and leak testing. I also enjoy developing techniques, preparing procedures, teaching inspectors how to use them, and then moving on to a new project. I have almost never been bored and have enjoyed working in the shipyard, ASME unfired pressure vessel construction, AWS and API weld inspection, radiography and CT of complex shapes such as castings, maintenance inspections of structures and used parts, raw materials, and more. My background has allowed me to participate in the design phase to help determine what and when to test by which methods and even participate in determining acceptance criteria. If you have ever been frustrated by some of these requirements in your own experience you know what a pleasure this is. It is true there are more jobs for inspectors than for engineers in NDT, but essentially the same thing is true of any career with multiple paths that can be followed. I was never unemployed from age 21 until I retired from full-time work at 69. There are always changes in technology, equipment, specifications and things that require NDT so the work has continued to be interesting. I am still working part-time for multiple clients at age 76 because people think they actually need me. I have been telling people I am not their long-term solution and trying to train replacements for me for several years. One thing I never expected to be important is that I realized when I was working on top of a domed stadium was that I could do a lot of my work from a wheelchair if I fell off and survived. For the past several months I have been working from a wheelchair, and people have been coming to me when I could not go to them. Now I can walk again but I’m not sure I should tell all of my clients about this. I can understand the point of view that very broad experience makes it hard to place a person in some types of jobs. To me the solution is to define the job you really want the most and get qualified for that. Engineers I have known working in NDT have had degrees in mechanical, electrical, chemical, material, metallurgical and welding engineering. Some jobs you may not have thought of include: Applications engineer for an NDT equipment manufacturer, work for an independent testing organization that works mainly in-house testing objects sent in by customers. These are likely to include CT, immersed UT and other fun techniques. Work in product design teams to establish what, when and how to inspect material as it becomes product in stages. Designing custom probes (for example eddy current and ultrasonic) to examine hard-to-reach places for maintenance inspections. Reviewing customer requirements for NDT before bidding on a prospective new job. This can be really funny or frustrating or both. You should also consider that it is almost impossible to honestly renew ASNT Level IIIs on the basis of points for more than 4 or 5 methods. There just isn’t enough time in 5 years. So you will need to be prepared to take exams every 5 years and some employers would only want to pay for the methods they need from you. In the civilian world, the certifications you need depend on the specifications your customers expect you to follow. I won’t start on that because you are probably tired of reading by now, but feel free to contact me directly if you wish. Good luck!!
Pin sets the zero reference every time the mirror rotates
IRIS is 0 deg inspection so it is for thickness. Cracks require angle beam
Hopefully this will help explain the differences:
GEOMETRY PIG: This is an intelligent pig which collects piping shape information (i.e. deformation such as dents, ovality, etc.) and the pipelines physical location in relationship to GPS coordinates. The IMU data from a Geometry Pig can be overlaid onto Google Maps and other software to determine it’s exact positon in relation to the earth. Typically a client will conduct a Geometry survey using a geometry pig prior to inspecting a pipeline or piping system with a MFL , Ultrasound or EMAT intelligent pig to ensure these pigs can make it through the pipeline without becoming lodged inside.
MFL PIG: This is an intelligent pig which applies the Magnetic Flux Leakage (MFL) NDE approach. This is the oldest intelligent pigging approach on the market.
NON TETHERED PIG: This is a pig which has no cables in front (towing) or trailing behind (sending data back to a main computer). Most intelligent pigs on the market today are Non Tethered.ULTRASONIC PIG: This is an intelligent pig which applies the Ultrasonic (UT) NDE approach. There are both Compression and Shear wave intelligent pigs being applied to inspect pipelines and piping systems.
EMAT PIGS: This is an intelligent pig which applies the ElectroMagnetic Acoustic Transducer (EMAT) NDE approach. This is the newest pigging approach on the market.
Sound velocity in metals does change with tension or compression. For example, the slowing of sound velocity under tension is a significant factor in applications involving bolt elongation measurement. However I have not heard of this as a practical problem when measuring wall thickness of typical pressurized tanks or pipes, since the effect is fairly small under most conditions. Whether the velocity changes during a hydrostatic test would be of functional significance in your case would depend on the pressure being applied, the elastic constants of the metal in question, and especially the measurement accuracy required.
Dear Sir,
Generally PWHT (post weld heat treatment) is called stress relieving (SR) treatment and its objective as applicable to carbon and low-alloy steel weldments is mainly to relieve the residual stresses caused by welding.
In this process the high hardness of the heat affected zone (HAZ) and also that of the weld are considerably reduced/homogenized, ductility and notch toughness are improved, and diffusible hydrogen is dissipated.
But the main aim of this PWHT is to relieve the harmful residual stresses.
When it comes to the reduction of hardness (like reduction of residual stresses), it depends on many factors like 1. Initial hardness and its distribution in weld metal, parent metal and HAZ. 2. The peak temperature used for stress reliving. 3. The duration of hold time at the peak temperature (which is arrived based on the thickness of the part/weld) 4. Cooling cycle chosen up to 300°C.etc.
Based on the composition the stress reliving temperature ranges from 550° to 675° C. For T22 material it can go up to 690° to even 720°. The SR temperature is very much dependent on the composition and the degree of reduction/homogenization required in the stresses.
The stress relieving temperature is normally kept below (normally by about 30°C) the tempering temperature known as Ac1, also called the lower critical temperature. If the temperature exceeds this (Ac1) more metallurgical changes occur where by hardness reduction is rapid. As such the SR is done below this Ac1 temperature. When the heat treatment is done above the Ac1 it is known as tempering.
In general higher the stress relieving temperature lower are the residual stresses and higher is the reduction in hardness.
Similarly if the hold time is on the higher side, higher is the reduction in hardness and residual stresses. Hold time at the peak temperature is generally given as one hour per/ inch of thickness, but in no case less than 1/2 hr, and the weld shall be allowed to cool slowly and uniformly.
Having said the above, please remember that the hardness reduction is not uniform in all the three zones, namely, weld, HAZ, and parent metal. Based on factors like welding method, composition of the parent metal and welding rod, preheat temperature, even the welding rod size (dia.), speed of the welding, inter-pass temperature the hardness can vary widely between weldments and HAZ. (Basically these are some of the factors that control the heat input during welding).
The hardness reduction after PWHT is dependent on its initial value and distribution, as measured before PWHT. At a given SR temperatures the HAZ hardness may come down steeply but not that of weld. The point is that after PWHT the reduction in hardness is not uniform in all the three zones.
The above are some of the general points governing the reduction in hardness in PWHT. If you give more details like composition, welding process etc. you may get more specific and better opinions from other experts.
Best wishes
There is no need to answer, because I found that “Part B” is mentioned between clauses 12.3 and 13 of ASTM A1038.
in the case of creeping waves. The model was made assuming elastic material. Then it is not possible an attemuation viscoelastic mechanism.
the atteniation in this case I think is related with geometrical considerations.
if you wish we can talk more by email
edmoreno52@gmail.comA thought-provoking and interesting post affecting practical NDT from you, David.
I wonder why the ASME Code is so much more restrictive than European Standards. Europe allows the use of flat blocks when testing girth welds. I suppose this is on the basis that, when parallel scanning, curvature is only an issue on very small OD’s when even a miniature angle probe may rock. Blocks may contain either 3mm side-drilled or 1 – 3mm flat-bottomed holes or 1mm notches. I think there is a thickness and material range which I cannot remember off-hand and I do not have the standards in front of me.
I think that the ASME requirements are often only paid lip-service. The Code is used worldwide throughout the oil & gas sectors as it is referenced by other US codes apart from BPV such as B31.3. Its not like ASME U-stamped vessels where an AI will be involved and will presumably check the blocks availability and (presumed) use. Where several remote piping fabricators are contracted ensuring conformance is made difficult by the Code, exacerbated by the Article 4 revision.
Has anybody run a sensitivity comparison between ASME and EN requirements? Surely they must be comparable. But entrencehed camps on both sides of the pond will ensure that standards globalisation is a long way off.As far as I can know is: “can” but only for the OD surface that probe can access. Eddy current can not penetrant as deep as 6mm to detect the ID notches. And also, if surface have the coating, sensitivity of method will be decrease
Alocrom is meant for surface protection against corrosion.However it has huge effects on the surface ispecially if you are going to do dye penetrant which requires the parent material to be completely exposed to the penetrant during inspection.Alocroming would basically mask indications since in this method we are interested in open to surface cracks.
Dear mates,
I have seen radiographic images of welds> 3 “made by DR and using Digital Detectors and no deformations are observed since the DDA is flat and cannot copy the curvature of the pipe such as a standard radiografic filmDestructive testing (DT) is a form of object analysis that involves applying a test to break down a particular material to determine its physical properties, such as the mechanical properties of strength, toughness, flexibility, and hardness. … Automobile crash tests are a well-known form of destructive testing.
Many, many years ago we developed an RT test for very basic evaluation of SCC.
Used a piece of tube the same diameter and WT as the boiler tubes to be tested we had 10 x grooves machined longitudinally on the inside of the tube.
That tube was then x-rayed.
The reference graph then gave us 10 x different densities based on the different groove depths to compare with the depth of the SCC seen in the subsequent radiographs taken in the boiler.
I know my story is of no help as you are talking about very advanced techniques, just thought I would share.If u cant radiograph the zone couse the concrete is the “floor” u should use GeoRadar, i dont know how its called in english…
anyone can help?
GeoRadar or GPR
http://www.caefendt.com.ar/index.php/georadar-gpr.html
Ground Penetrating Radar
In the ASME is written :
(-b) The depth of the flaw shall be drawn normal to the inside pressure retaining surface and shall be denoted as “a” for a surface flaw or “2a” for a subsurface flaw.For me denoted means it is written as “a” for surface flaws and written as 2a for subsurface flaws.
So it is not allowed to take 2 time a for subsurface flaws. it is just written this wayWhy not ????
There are millions of inspections done with paint & coating on the surface – only in very special cases coatings are removed. Coating removals could harm structures more than acceptable if the structure shows by NDT to be o.k. (especially in Aerospace).
Environental degraded, aged, dirty and flaking coatings should be removed sa they don’t do the job, than first remove it and afterwards inspect it.
If your inspection procedure, you have written turns out to be critical dealing with the coating, improve it! Usually that is possible by changing freqency signal shape, filter or other instrument settings, tuning / changing the transducer or the delayline, introducing a further inspection step. Use modelling e.g.by CIVA.Basic industries produce materials, which are in term used for Other industries. the chemical industry uses raw materials to produce product suggest acids, bases,alkalis and salts. … So, we can say that the chemical industry is a basic industry.
When is cathodic protection required? In general, any metal tanks and metal appurtenances such as piping, valves, and connectors that are in contact with soil and routinely contain a regulated substance must have CP.
One of the best AUT system I know of is the REVOLUTION System of Weldsonics. It is designed and made for your task. You may visit http://www.weldsonix.com for further details.
good luck: Dear friends,
: We are interested for automated ultrasonic testing of welded pipe joints of cross country pipeline during construction stage.
: Could you please let us know best instrument manufactuers / service providers(Hi,
Following my fist message, please note that the webinar is ready.
It will deal with simulation of NDT in the Aeronautic and Aerospace sectors and will take place on the 22nd and 25th of May 2018.
Feel free to register to one of the two sessions under this link: https://docs.google.com/forms/d/e/1FAIpQLSf9Q5F4ZBoK6e17SIDglbqjbCIxrbAMPp5cQKBO2aOvJNBG1A/viewform?usp=sf_link(I will agree 100% with Hunter. The kind of AE inspection and reporting is being done now-a-days and is being thrown to clients is simply unacceptable technologically as well as professionally. Acoustic Emission testing is being treated technically as well as commercially, as any routine, manual, instant machine results-based technology for Go-NO GO kind of results, short changing many unsuspecting or not well-informed clients. This is a real tragedy and amounts almost to an insult to the capacity and capability of Acoustic Emission technology itself. Early defect detection/quantitative defect estimation, in current scenario, is a far cry in the wild.)
I have compiled a short list i had already im my files:
at first: Check the internet for Presentation,Lectures, Papers of Uwe Ewert and Uwe Zscherpel from BAM, already here in NDT
