Comparision of UT & RT ( Justifying UT )

[Rana Vikas]

Dear All,

 

We awared Hydro power project. There is specifically requirments of NDT method RT for all weld joint ( i.e for all class of joint ).

 

We never used RT in normal practice for all project. Now for convince to client We required comparision sheet between RT & UT to justifying UT is better than RT.

 

Request to send Comparision of RT & UT. Please send comparision & revert back soon. We have to submitt QAP urgentely.

 

 

Regards,

 

Vikas Rana

 

[sachin sankhe]

 
Dear Vikas,

You have ask question in very broad prespective.

Their are many reason to say RT is better that UT.

But to convice exactly opposite to your client you need to give some more details like

1.Type of material i.e pipe or plate
2.Size-Thickness,Dia.....

Above all design code

Note that if design code ask for RT then in no way u can escape from RT unless code give relaxation in case of joint whose RT is not possible due to complex joint configuration.

Regards
Sachin

Sachin.Sankhe
Engineer-Inspection
Aker Kvaerner-Malaysia
Mobile:012-2896901
Email1:Sachin...@akerkvaerner.com
Email2:Sachin...@rediffmail.com

[Rana Vikas]

His, Sachin

 

Thanks for reply.

 

There is requirments in contractual documnets of project. I am talking about Hydro power project. It include components like  Turbine,Generator, Valve etc..

 

Normaly the grade of material for plate - A516, A283,SS304 ( Thickness renging from 10 to 250mm ) & Casting - A743 CA6NM  

 

We never conduct RT in manufacturing yet. So to convince client we required general comoparison stating to UT against RT.

I am great thanksful if you can provide the comparision considering below factor. cost,time dellivery ( OTD ),Saftey,sensitivity etc..

 

Revert back soon , Queries are invite

 

Thanks,

 

Vikas Rana

[Tahir Olmez]

RELATIVE ADVANTAGES AND WEAKNESSES OF RADIOGRAPHY VS ULTRASONIC, TWO COMPLEMENTARY TECHNIQUES Ultrasonic and radiographic examination methods are complimentary and are not directly comparable or equivalent. Depending on flaw type (i.e., volumetric or planar) and orientation, ultrasonic examination may be superior to radiography or vice versa. Radiography is most effective in detection of volumetric type flaws (i.e., slag and porosity) and detection of planar type flaws (i.e., lack of fusion and cracks) that are oriented in a plane parallel to the x-ray beam. However, radiography is limited in detection of planar flaws not oriented parallel to the beam. In contrast, ultrasonic examination is very effective in detection of planar type flaws that are not oriented in a plane parallel to the sound beam .... Finally, ultrasonic examination is capable of detecting volumetric type flaws such as slag or porosity but is limited, compared to radiography, in ability to characterize volumetric flaws. The proposed alternative ultrasonic examination requirements and provisions address the known limitations of the ultrasonic method to ensure both planar and volumetric flaws in all orientations are detected and properly evaluated. First, examination using two angle beams (i.e., 45 and 60 degree nominally) or a procedure qualified on 100% of the weld volume in accordance with the performance demonstration methodology of Section XI, Appendix VIII is required. Second, examination scans in two directions perpendicular to the weld axis and two directions parallel to the weld axis or examination scans as qualified on 100% of the weld volume in accordance with the performance demonstration methodology of Section XI, Appendix VIII is required. Third, to ensure laminar type flaws are detected, a supplemental examination using straight beam is also required. Finally, if an indication, such as slag or porosity, is not characterized as volumetric, the indication will be characterized as a planar type flaw and evaluated in accordance with the acceptance criteria of NC-5330. The acceptance criteria of NC-5330 specify acceptable lengths of indications only and do not differentiate between planar and volumetric type flaws. Most importantly, planar type flaws such as cracks, incomplete penetration, and lack of fusion, which are rejectable by NC-5330 for any size, are more readily and properly characterized by ultrasonic examination. In addition to the effectiveness of the proposed alternative, use of ultrasonic examination in lieu of radiography will provide a significant reduction in personnel radiation exposure during refueling outage maintenance work. Also outage duration and costs will be reduced by allowing parallel path work to progress uninterrupted during examination of welds. Finally, the personnel safety risk of inadvertent or accidental exposure and also the normal anticipated exposure associated with transporting, positioning and exposing a source for radiography is eliminated. Source: D. Naujock et al. (NRC Office of Nuclear Reactor Regulation), http://www.nuclear.com/archive/2003/07/13/20030713-002.html Callaway-1 10-yr pipe test ISI - UT approved in lieu of radiography , nuclear.com info nugget 20030713-002, July 1, 2003] Tahir Bilge Ölmez International Welding Engineer

[Shashank Vagal]

Gents,

I would suggest first UT scan for root zone preferably with 70 deg probe of as high frequency as feasible. If any flaws exist in root, unless they are attended to, all further inspection activity is not justified.

 

With Bets Regards,

Shashank C Vagal     

--
To post to this group, send email to material...@googlegroups.com
To unsubscribe from this group, send email to materials-weld...@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm
 
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-weld...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

[manisch .]

As far as the comparison of RT that with the UT is concerned there have been numerous studies to find out the probability of defect detection, namely POD with both the methods.

The main distinguishing factor between selecting a method among these two can be,

i) Joint efficiency required

ii) Likelihood of orientation of defects, defect geometry

iii) Joint Access

Furthermore, the most important factor SAFETY argues to opt for UT as much as possible for  assessing weld quality of field or open joints. The process variables associated with RT and their control is a key factor in getting the optimum results. Whereas in UT, with advanced techniques can cover and detect a wider defect field with less time and recordable reporting. And the overall assurance of UT is better then RT, as the defect size and location can be accurately determined, as not in case of RT.

UT is has seen a lot of advancement since its inception, the techniques as Phased Array and Time of flight diffraction come with higher POD as compared to RT.

Please, find the attached paper, examining defect characterization and a case study
( thanks to the researchers)!!! 

Thanks and Regards,

Manish Kumar

--

To post to this group, send email to material...@googlegroups.com
To unsubscribe from this group, send email to materials-weld...@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
http://www.linkedin.com/groups/MaterialsWelding-122787?home=&gid=122787&trk=anet_ug_hm
 
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-weld...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

--
Manisch Kumar,

email- tetr...@gmail.com,tetra...@rediff.com

[Steven Teo]

Thanks Tahir for copy+paste the right thing which is very informative. However, the real thing is that we are at the mercy of NDT operator/s whom choose to cheat  ...eg...an UT operator would take half a day to examine a 300mm welded plate specimen in a classroom under test to be certified. In actual field production, the same length would be done in no time literally speaking. Truth be told. Thats the main reason why client insisted on black+white RT evident of proper NDT to be implemented.

NDT malpractises (be it UT, RT, MT, PT, etc) are wide spread in oil/gas/shipbuilding industries except probably medical. Even for the interpretation of NDT result, the better convincer wins....just as in school debate.

--

[Tahir Olmez]

Dear Steven , by RT you cant detect planar flaws parallel to xray beam and UT is very usefull with its flexible usage and cost efficency , pls tell me about what type of alloy and welding method used at to be controlled welds i may inform you more details for UT , and if you have any doubt about the NDT personel tell them on any problem of work they will have legal problems if they have any major mistakes on controls .

Tahir Bilge Ölmez
International Welding Engineer

Mat. & Met. Eng.
Atlantic Marine Survey
Verify Europe
+90 544 615 8801
+90 326 615 8801
tahir...@gmail.com

[Sam]

dear sir,

just confusion, i think in RT we can detect planar flaws which are parallel to x-ray beam and can not if not parallel ?

pls clarify me.

[manisch .]

Dear Sam,

RT cannot detect planar defects parallel to the direction of incident radiation or in other words the probability of detection is less, but  the defects perpendicular to the radiation can be radio-graphed.

Meanwhile, the specimen or test-piece can be reoriented and re-shot, so as to get the optimum results by detecting the so called parallel defects from the different beam incident angle.

And this is not the scenario in case of real-time radiography.  

[Tahir Olmez]

Yes right , i forgetten "not"

You received this message because you are subscribed to a topic in the Google Groups "Materials & Welding" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/materials-welding/XfJ-uN8RiqM/unsubscribe.
To unsubscribe from this group and all its topics, send an email to materials-weld...@googlegroups.com.

For more options, visit https://groups.google.com/groups/opt_out.

--

>Tahir Bilge Olmez

>International Welding Eng.

>Met. & Mat Eng.

>Verify & Atlantic Marine

>+90 544 6158801

[Parth Hingu]

Pls explain in brief about Acceptance criteria comparison for RT,UT, PT (Casting/ Forging) as per ASME, EN,ASTM standards?

[MADHUSOODHANAN NAIR .G]

Dear Rana

    Carefully read below mentioned details for your information.

ULTRASONIC TESTING

UT is used to locate surface and sub surface defects in many materials plastics and wood. It is also used to measure the thickness of the materials

ADVANTAGES OF UT

1.       It is sensitive to both surface and sub surface discontinuities.

2.       The depth of penetration for flaw detection is superior to other NDT method.

3.       Only single sided access is needed when the pulse –echo technique is used.

4.       It is high accuracy in determining and estimating size and shape.

5.       Fast result and very sensitive to planar type discontinuity.

6.       Applicable for thick materials

DISADVANTAGES OF UT

1.       Surface  must be accessible to transmit ultrasound

2.       Skill and training is more extensive than with other methods.

3.       It normally requires a coupling medium ( except LR UT) to promote transfer of sound energy into the test specimen.

4.       Materials that are rough irregular in shape very small, exceptionally, thin or not homogeneous are difficult to inspect.

5.        Cast iron and other course grained materials are difficult to inspect due to low sound transmission and high signal noise.

6.       Linear defects oriented parallel to the sound beam may go undetected.

7.       Reference standards are required for both equipment calibration and characterization of flaws.

8.       Not capable of detecting defect whose plane is parallel to the direction of sound beam.

RADIOGRAPHY TESTING

The radiation used in radiography testing is a higher energy version of the electromagnetic waves .The radiation can come from an X-Ray generator or a radioactive source.

ADVANTAGES OF RT

1.       Used to inspect almost any material for surface and sub surface defects.

2.       It can also be used to locates and measures internal features, confirm the location of hidden parts in an assembly.

3.       Ability to inspect complex shapes and multi-layered structures without disassembly.

4.       Minimum part preparation is required.

5.       Capable of exposing fabrication errors at different stages of fabrication

DISADVANTAGES OF RT

1.       Extensive operator training and skill required.

2.       Access to both sides of the structure is usually required.

3.       Orientation of radiation beam to non volumetric defects is critical.

4.       Higher thickness radiography can be time consuming.

5.       High experience need to proper interpretation of results.

6.       Time consuming for result.

7.       RT film is a permanent record of testing in the form of hard report.

8.       Two dimensional image of defect is much easier and clear to interpret.

9.        Job temperature should not exceed 60Deg .

10.   Film is very sensitive to temperature, pressure and humidity.

Regards

Madhusoodhanan Nair.G

09967901872

Sr Inspector (VCS Quality Services Pvt Ltd,Mumbai)

--

You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-weld...@googlegroups.com.

To post to this group, send email to material...@googlegroups.com.
Visit this group at http://groups.google.com/group/materials-welding.
To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/2de5b950-c3ff-4b99-9dc2-b89cdde86c90%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Kannayeram Gnanapandithan]

How comfort in RT to detect Planer defect like Incomplete Fusion?? compare with UT

THANKS & BEST REGARDS

KG.PANDITHAN, AWS-CWI, CSWIP 3.1

CONSULTANT-WELDING & QUALITY

To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAE12Qq7iAaokWpbMQ%2Bw7Ctni5w60EZwQbkvSVx3-H%3D1nqu_0aA%40mail.gmail.com.

[Alan Denney]

In radiography there has to be a difference in the material along the path of the beam for a defect to show up. If the beam aligns with the lack of fusion then it should be apparent, but normally the beam is not aligned along the defect. For example if you are welding with a 60 degree bevel and the lack of fusion is on the bevel surface the beam, which is aligned perpendicular to the surface will see no path or density difference in the material and hence it will not be registered on the radiograph.

To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAJzm4eN8KLCtFDRAZBp6%3DwbQXJ_5%2BR%3DOXZwG0UETYQw5cBLjag%40mail.gmail.com.

[pgoswami]

Hi Vikas,

 

In ASME or in other design and construction codes, the volumetric NDE criteria is based on RT. The issues are as follows:-

• RT at any point of time can cover more areas for volumetric inspection than Conventional Pulse Echo UT
• RT reports (together with films) can be well documented  and preserved for future recordkeeping.
• Same is not possible for conventional UT as , one gets only the report ( kind of a go no go scenario)

Modern digitized UT techniques e.g PAUT or TOFD are accepted in lieu of UT, under specific code cases( see the attachment).

 

Hydro turbines do not follow any BPV codes.Hence it very difficult to quantify the specific technique and it's acceptance criteria. However given a choice:-

 

1. Use RT wherever possible,  the as stated above
2. RT may be replaced by PAUT or TOFD.
3. If the product is turbine runners  Pulse Echo UT will  just  be  a black-hole. One may not get the back wall echo due curvature causing mode conversion. PAUT/TOFD would be lot beneficial for such welds.

Note:- In addition to the preferred  NDE technique one has to specify the acceptance criteria.  Which design code one should follow????

 

These are some of the points worth considering.

 

Thanks.

 

Pradip Goswami, P.Eng,IWE

Welding & Metallurgical Specialist

Ontario, Canada

pgos...@quickclic.net

pradip....@gmail.com

http://ca.linkedin.com/pub/pradip-goswami/5/985/299

 

---

From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Alan Denney
Sent: Friday, January 02, 2015 5:52 AM
To: material...@googlegroups.com
Subject: RE: [MW:22673] Re: Comparision of UT & RT ( Justifying UT )

To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/005101d0267a%2414e1c3b0%243ea54b10%24%40denney1.freeserve.co.uk.