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 -

1878 views
Technical Discussions
Heavy Métal Inspection
Heavy Métal Inspection
03:45 Sep-16-2009
UT shaft inspection

Hi

I have to inspect a 1 1/2" diameter shaft about 6" long for cracks. My only access is by one end. What would you recommend?
-a small diameter with high frequency or
-a large diameter with low frequency

Thank you

 
 Reply 
 
P V SASTRY
R & D, NDT tecniques metallurgy
TAKEN VRS FROM THE POSITION OF SR. DEPUTY GENERAL MANAGER BHEL CORPORATE R&D, India, Joined Jan 2003, 195

P V SASTRY

R & D, NDT tecniques metallurgy
TAKEN VRS FROM THE POSITION OF SR. DEPUTY GENERAL MANAGER BHEL CORPORATE R&D,
India,
Joined Jan 2003
195
13:40 Sep-16-2009
Re: UT shaft inspection
In Reply to Heavy Métal Inspection at 03:45 Sep-16-2009 (Opening).

Hi,

It is essential to know how the shaft has been made and the present service condition/stress direction before deciding the UT technique.

If it is assumed that the shaft is made by forging then it is the convention to direct the ultrasonic beam in the same direction as that of major working. In the case that you mentioned this direction happens to be the cylindrical surface and not the end faces.

Secondly you are looking either for transverse cracks as in the case of fasteners/bolts or longitudinal cracks.

If you are looking for transverse cracks it is always better to use a small dia. high frequency probe.

If you are looking for longitudinal cracks, scanning from one end using conventional techniques is not going give any useful results. Special techniques using pitch and catch configurations (with conventional UT) or sartorial scans with Phased array probes have to be standardized.

The way you have put, it looks that you want to scan a fastener/bolt which is in tightened condition. If it is so the cracks are expected in the transverse direction only but the problem is that they are invariably initiated in the threaded area.

While you can use small dia. (about 10 mm) high frequency about (4 to 6Mhz) probes for this purpose, utmost care is required to discern the incipient cracks from the standard multiple indications emanating from the threads. Careful marking is required with known crack sizes and it is prudent to use a 5mm dia. transducer for marking and scanning for incipient cracks in threaded region.

Wishing well

P V SASTRY

 
 Reply 
 
Manuel Haces
Director, - Wire rope inspection
Haces Inspección del Noreste and Wire Rope Inspection, Mexico, Joined Jun 2002, 125

Manuel Haces

Director, - Wire rope inspection
Haces Inspección del Noreste and Wire Rope Inspection,
Mexico,
Joined Jun 2002
125
02:58 Sep-17-2009
Re: UT shaft inspection
In Reply to Heavy Métal Inspection at 03:45 Sep-16-2009 (Opening).

You can have very good ref. Ultrasonics by Krautkramer & Krautkramer, an old book. It is common to have geometry reflectors, so better to have a croquis and where to expect reflections due to this condition. Regarding the size of the transducer, you should consider the spreading of the beam. I would use 1 or half inch diam and 2 Mhz, at first instance. If you post more information it would be possible to give you a better idea. I mean how this shaft is working, where are the different sections, change in diameter, and so on. Regards

 
 Reply 
 
Michel Couture
NDT Inspector,
consultant, Canada, Joined Sep 2006, 893

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
893
17:37 Sep-19-2009
Re: UT shaft inspection
In Reply to Heavy Métal Inspection at 03:45 Sep-16-2009 (Opening).

One specification that is used frequently by my customers for this kind of work is ASTM A388. Basically your transducer is 2.25 MHz, a surface area not to exceed 1 square inch and a diameter between 0.75 to 1.125 inch. In your situation, I would chose the smallest diameter allowed to get best contact. The specification allow for Back Wall REflection, DGS or DAC Curve to be used.

This specification is a generic one for forgings and quality level should be determined by the client.

 
 Reply 
 
Heavy Métal Inspection
Heavy Métal Inspection
03:54 Sep-21-2009
Re: UT shaft inspection
In Reply to Michel Couture at 17:37 Sep-19-2009 .

Hi

First thank you for all that help.

In fact, what I have to inspect are shafts used in scisor lift (the ones that make the scisor).
It is made of cold roll steel, probably 1018 or mybay a bit srtonger. It is strait, without any different section, only one hole perpendicular to the lengh.
What I am looking for are fatigue cracks for normal or abusive uses.

Thank you

 
 Reply 
 

Product Spotlight

SITEX CPSERIES

Teledyne ICM’s CPSERIES has been designed with a view to revolutionizing the handling and perfor
...
mances of portable X-Ray sets. Despite having managed to halve the weight of similar portable X-Ray generators available on the market (while continuing to provide the same power output), the SITEX CPSERIES generators feature a shutter, a laser pointer, a beryllium window, an aluminum filter and two integrated diaphragms (customized sizes are available upon request). Without compromising the robustness and reliability for which ICM products are renowned, the small size and light weight of the SITEX CPSERIES will radically change the way that you perform your RT inspections. And you will see a positive impact in terms of both quality and return on investment (ROI).
>

Combination of Digital Image Correlation and Thermographic Measurements

The combination of measuring results from the digital image correlation (ARAMIS, DIC) and temperat
...
ure measuring data from infrared cameras permits the simultaneous analysis of the thermal and mechanical behavior of test specimens in the materials and components testing field.
>

Extended Range Variable Wall® Piping Calibration Blocks for Longseam Inspection

This set of two blocks has been specially designed for situations where ultrasonic examination tak
...
es place circumferentially or “around the curve” for applications such as inspection of longseam welds in piping and vessels. Jointly designed by PH Tool and Holloway NDT, the blocks feature side-drilled hole reflectors positioned within novel compound-curves, each with multiple thickness steps. The unique design results in a light and compact form factor, with the largest block weighing just over 15 lbs and spanning just 16 ¾”. Coverage is provided for nominal pipe sizes from 6” to 10” in the small block and 12” to a whopping 56” in the large block. The compound OD curves and multiple wall thicknesses actually exceed ASME requirements, providing exceptional signal response and measurement accuracy. Properly managing beam divergence off the ID and stabilizing beam skew due to probe rocking is essential to maintaining a consistent calibration when inspecting lengthwise on curved surfaces.
>

Ultrasonic Testing Immersion Tanks with Unmatched Scanning Features

TecScan’s non-destructive testing Ultrasonic Immersion Tanks & scanners are designed for high pe
...
rformance and demanding NDT testing applications. Our Scan3D™ line of High Precision Immersion Tanks are specifically designed for automated ultrasonic testing of complex composites parts used in aerospace and industrial 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