where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -

1099 views
Technical Discussions
António Pereira de Sousa
António Pereira de Sousa
02:03 Nov-23-1999
Dissimilar Welds

On 460 welds, between SA213T99 and SA213T22(tubes with 0.5x5mm) has been made a magnetic particle testing.
They were detected 50% of welds with longitudinal linear indications on side TA213T91.
After retesting, by Penetrant testing, only 10% of them have shown indications from cracks.
Why?



 
 Reply 
 
Michael Trinidad
Consultant,
LMATS Pty Ltd , Australia, Joined Jan 2003, 141

Michael Trinidad

Consultant,
LMATS Pty Ltd ,
Australia,
Joined Jan 2003
141
03:46 Nov-24-1999
Re: Dissimilar Welds
This would most likely be the indications from the magnetic leakage field occuring around the large change in permeability between the two disimilar metals. It has often caught out technicians, we had a similar case in the fourm only a few months back.

Kindest Regards

Michael Trinidad


 
 Reply 
 
D. Scott Sullivan
D. Scott Sullivan
01:57 Nov-24-1999
Re: Dissimilar Welds

: This would most likely be the indications from the magnetic leakage field occuring around the large change in permeability between the two disimilar metals. It has often caught out technicians, we had a similar case in the fourm only a few months back.

: Kindest Regards

: Michael Trinidad

: Mr. Trinidad's opinion is most likely correct. Another possibility could be that you were picking up indications of sub-surface lack of fusion with the magnetic particle method. If the lack of fusion was subsurface, the penetrant method would not detect it.
If you cut a cross section and etch the weld, you could confirm this. If you can not cut the weld, a X-ray of the suspect area should be able to readily detect lack of fusion.

:D. Scott Sullivan
Sr. NDT Engineer
RT, ET, MT & PT Level III


 
 Reply 
 
Ken Head
Ken Head
07:56 Nov-24-1999
Re: Dissimilar Welds
:
: : This would most likely be the indications from the magnetic leakage field occuring around the large change in permeability between the two disimilar metals. It has often caught out technicians, we had a similar case in the fourm only a few months back.

: : Kindest Regards

: : Michael Trinidad

: : Mr. Trinidad's opinion is most likely correct. Another possibility could be that you were picking up indications of sub-surface lack of fusion with the magnetic particle method. If the lack of fusion was subsurface, the penetrant method would not detect it.
: If you cut a cross section and etch the weld, you could confirm this. If you can not cut the weld, a X-ray of the suspect area should be able to readily detect lack of fusion.

I think you are mistaken on using X-Ray to determine the presence (or
lack there of) of fusion. As a rule, radiography is not the perferred
method for detecting "non-fusion". the method most suited for this task
is UT.
Ken Head
Sr. Level III
: :D. Scott Sullivan
: Sr. NDT Engineer
: RT, ET, MT & PT Level III




 
 Reply 
 
D. Scott Sullivan
D. Scott Sullivan
06:03 Nov-29-1999
Re: Dissimilar Welds
Ken,

I don't believe I am mistaken regarding the detection of sidewall lack-of-fussion (LOF).

X-ray would be the preffered method. Although you can detect LOF with the ultrasonic method, LOF, weld root cracks and lack-of-penetration (LOP) all give essentially the same type of ultrasonic signal. The reflected signals are narrow and appear at the same location. These signals can in some cases be differentiated by determining the extent of the flaw in the transverse direction. This is not always possible.

In any case, as far as a back-up inspection to MT, I agree that RT or UT could quickly confirm wether or not the MT indication was relevant.

Best Regards,

D. Scott Sullivan



 
 Reply 
 

Product Spotlight

TraiNDE UT

TraiNDE UT is a virtual tool associated with a signal database which simulates real inspection con
...
ditions for numerous applications (Type A/V1 block, DAC block, welds and plates).
>

Magnetic X-Ray Pipeline Crawler 6''-60''

Suitable to work in 6''-60''diameter with speed of up to 18m/min, Max. moving diatance 5 kilometer
...
s and provide the efficient inspection of the pipeline.
>

Sci Aps Z-Series Portable Handheld Analysers

The world’s only handheld analyzer that measures carbon content in stainless (yes even L-grades),s
...
teels, and cast irons. Also accepted for low Si analysis for sulfidic corrosion analysis, and is widely used in the power industry for Cr analysis, for flow accelerated corrosion applications.
>

ISAFE3 Intrinsically Safe Sensor System

ISAFE3 intrinsically safe sensor system of Vallen Systeme is especially targeted at the petrochemica
...
l - as well as oil and gas transportation industry. The sensor system is designed for permanent monitoring or periodic inspection tasks. Sensors are available for different AE-frequency ranges optimized for corrosion and fatigue crack detection and other applications. The ISAFE 3 sensor system consists of an AE-sensor (model ISAS3) certified according to ATEX/IEC for installation in zone 0, gas group IIC, IP68, 20 to +60 °C, and a signal isolator (model SISO3) certified for installation in zone 2. An ISAS3 sensor can be mounted in atmosphere or submerged, e.g. in water or crude oil. It is supported by mounting tools for temporary (magnets) or permanent (welded) installation. ISAFE3 supports automatic sensor coupling test and can be used with any AE signal processor supporting 28V supply at 90 mA peak, e.g. Vallen Systeme ASIP-2/A.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window