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 -
802 views
Technical Discussions
cln
cln
16:44 Dec-06-2016
Magnetic Particle Inspection

Ok so, i have a 3" wide weld that is ground smooth (66" O.D. Vessel) and i am performing MPI. I am going to straddle the weld on the 1st inspection then for my second inspection i will be rotating my yoke 90 degrees which will place it directly on the weld. Is it acceptable to place the yoke on the weld as long as i am getting full coverage with my overlap? If that is unacceptable, where in any code could i find this because it is not stated in ASME Sec. V

 
 Reply 
 
Nigel Armstrong
Engineering, - Specialist services
United Kingdom, Joined Oct 2000, 1096

Nigel Armstrong

Engineering, - Specialist services
United Kingdom,
Joined Oct 2000
1096
14:00 Dec-07-2016
Re: Magnetic Particle Inspection
In Reply to cln at 16:44 Dec-06-2016 (Opening).

Determine the maximum pole spacing at which the yoke can lift the 4,4 kg block. If ıts at least 100mm then, as the weld cap is ground flush, you can position the yoke obliquely to the weld centre line (making sure the poles clear the HAZ +6mm on either side of the weld) and make your first shot. Repeat at 90 degrees to the first energisation to cover the same area of weld with the magnetic flux perpendicular to the first shot.. In this manner any orientation of discontinuity will always be at between 45 and 90 degrees to the magnetic flux.

You dont need to place the pole pieces on the weld metal at all. ASME V Article 7 may not specifically state that the yoke feet should not rest on the weld metal because usually this is not viable with unground weld caps.

 
 Reply 
 
Dent
Consultant, NDE Manager NDELevel III/3
NDT Consultant, Canada, Joined Nov 1998, 250

Dent

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
250
21:18 Dec-07-2016
Re: Magnetic Particle Inspection
In Reply to cln at 16:44 Dec-06-2016 (Opening).

There is nothing wrong with your technique. Nothing prohibits placing the yoke leg on the weld provided you achieve the overlap as you say you do.
I actually prefer your technique since the most likely direction of flaws is parallel to the weld axis, and in some cases (transverse cracks or backing bar joints not removed) right angles to the weld axis. Your technique will optimize the indications from such flaws. Several NDT schools teach the x technique, but for the very best chance of finding axial indications I prefer your way.

 
 Reply 
 

Product Spotlight

Immersion systems

ScanMaster ultrasonic immersion systems are designed for high throughput, multi shift operation in a
...
n industrial or lab environment. These fully integrated systems provide various scanning configurations and incorporate conventional and phased arrays technologies to support diverse applications, such as inspection of disks, bars, shafts, billets and plates. All of ScanMaster immersion systems are built from high accuracy scanning frames allowing for scanning of complex parts and include a multi-channel ultrasonic instrument with exceptional performance. The systems are approved by all major manufacturers for C-scan inspection of jet engine forged discs. Together with a comprehensive set of software modules these flexible series of systems provide the customer with the best price performance solutions.
>

Compact NDT inspection-heads for measurements with active thermography

The compact inspection head is suitable for thermographic ndt tasks. The uncooled infrared camera
...
is specially developed for NDI-tasks and offers a thermal sensitivity until now known only from thermal imagers with cooled detector. All required components and functions are integrated into the inspection-head. You will only need an ethernet cable to connect the sensor with the evaluation system.
>

HARDNESS TESTER TKM-459CE combi

TKM-459CE combi applies 2 methods of hardness control: UCI and Leeb. It provides high-accuracy tes
...
ting of metals and alloys as well as items of different sizes and configurations, their hardened layers and galvanic coatings. Device represents results in HB, HRC, HV and others. Shock-, dust- and water-proof housing with intuitive software make this gauge easy to use in all working conditions.
>

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.
>

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