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 -

Sonotron NDT
Original developer and manufacturer of advanced ultrasonic instruments
1908 views
Technical Discussions
MM Damani
MM Damani
00:00 Feb-12-2003
Hidden Crack in Graphite Electrodes

USE OF ACOUSTIC RESONANCE FOR DETECTING HIDDEN CRACKS IN GRAPHITE ELECTRODES”


Q.1 Whether Acoustic Resonance method uses mechanical waves having sinusoidal oscillations?

Q.2 Whether the Instrument is capable to detect cracks, extrusion defects, cavities, porosity etc. in Carbon / Graphite Electrodes?

Q.3 If yes what the level of Precision and repeatability of Test?

Q.4 Whether it is possible to check carbon / Graphite Cylindrical Rods of diameter ranging between 250 mm to 700 mm and length between 1800 mm to 3000 mm?

Q.5 Is it possible to carryout Acoustic resonance test on Pitch Impregnated Carbon Rods for ascertaining pitch pickup level after impregnation?



 
 Reply 
 
Godfrey Hands
Consultant,
PRI Nadcap, United Kingdom, Joined Nov 1998, 303

Godfrey Hands

Consultant,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
303
01:49 Feb-14-2003
Re: Hidden Crack in Graphite Electrodes
Hi There,

My company uses the Quasar Resonant Inspection equipment for inspecting components. This uses a sinusoidal wave to excite the parts mechanically.

We are normally able to detect Cracks, Extrusion defects, Cavities, Significant amounts of Porosity and many other conditions in Metal and Ceramic components, as well as Ferrite. To my knowledge, we have never tested Graphite electrodes, but as the technology is quite new, it will only be a matter of time before it is tried on Graphite.

We normally measure resonances with a precision of "a few Hertz" for optimising testing speed, but the system has a resolution capability of 1 Hz. Our measurement errors (repeatability) are typically 0.01% or smaller at higher frequencies, and perhaps 0.05% at lower frequencies.

We normally test components in the weight range 20 Grams to 20 Kilograms, but are currently experimenting with components around 50 to 70 Kg. I see no reason why the technology shouldn't test your electrodes.

I think that it is unlikely that we will be able to determine the pitch pickup level of pitch impregnated electrodes, but cannot rule this possibility out.

Please provide your location, and I can arrange that your nearest Quasar Application Engineer or Sales Person contacts you to make some trials on some of your electrodes.

Regards,

Godfrey Hands

-------------------------------------
: USE OF ACOUSTIC RESONANCE FOR DETECTING HIDDEN CRACKS IN GRAPHITE ELECTRODES”
.
:
: Q.1 Whether Acoustic Resonance method uses mechanical waves having sinusoidal oscillations?
.
: Q.2 Whether the Instrument is capable to detect cracks, extrusion defects, cavities, porosity etc. in Carbon / Graphite Electrodes?
.
: Q.3 If yes what the level of Precision and repeatability of Test?
.
: Q.4 Whether it is possible to check carbon / Graphite Cylindrical Rods of diameter ranging between 250 mm to 700 mm and length between 1800 mm to 3000 mm?
.
: Q.5 Is it possible to carryout Acoustic resonance test on Pitch Impregnated Carbon Rods for ascertaining pitch pickup level after impregnation?
.



 
 Reply 
 
Lalit Chandra
Lalit Chandra
08:03 Mar-27-2015
Re: Hidden Crack in Graphite Electrodes
In Reply to Godfrey Hands at 01:49 Feb-14-2003 .

Dear Sir,

I am working in a graphite manufacturing plant. very much interested to know the results of any test/experiments with graphite cylindrical rods.

if your company did any experiment to detect cracks inside these electrode rods please let us know.

lalit

 
 Reply 
 
Godfrey Hands
Consultant,
PRI Nadcap, United Kingdom, Joined Nov 1998, 303

Godfrey Hands

Consultant,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
303
12:29 Mar-27-2015
Re: Hidden Crack in Graphite Electrodes
In Reply to Lalit Chandra at 08:03 Mar-27-2015 .

Hi,
I no longer work directly with this company, but I can get more details sent to you.
Please provide me with contact details to my email address.
Please use the email option in NDT Net.

Regards,

Godfrey Hands

 
 Reply 
 
Godfrey hands
Consultant,
PRI Nadcap, United Kingdom, Joined Nov 1998, 303

Godfrey hands

Consultant,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
303
16:31 Jan-19-2017
Re: Hidden Crack in Graphite Electrodes
In Reply to Godfrey Hands at 12:29 Mar-27-2015 .

Hi,
I have recently had another enquiry about testing Graphite Electrodes with this technology.

Back in 2003 when this idea was first considered, this technology was very new, and nobody knew exactly what potential there was for inspecting Graphite electrodes, although it had been considered a possibility.
14 years later, and we now know a lot more about what can be done and what is doubtful, and inspection of large Graphite Electrodes now appears to fall into the "Doubtful" category, although some limited success has been reported for inspecting Graphite components of up to about 2Kg for major defects.

The technology is however still an excellent tool for mass-production of smaller metallic or fired ceramic components.

Godfrey

 
 Reply 
 
Krishna Bhuta
Director,
Own, India, Joined Jun 2014, 6

Krishna Bhuta

Director,
Own,
India,
Joined Jun 2014
6
08:34 Jan-23-2017
Re: Hidden Crack in Graphite Electrodes
In Reply to Godfrey hands at 16:31 Jan-19-2017 .

Hi, I had worked on this project some tiem back, its possible to carry out UT inspection fro mass production too if require.

 
 Reply 
 
Simon Amallraja
Consultant, Advanced NDT Methods
Anu Consultants, India, Joined Aug 2013, 38

Simon Amallraja

Consultant, Advanced NDT Methods
Anu Consultants,
India,
Joined Aug 2013
38
15:06 Jan-23-2017
Re: Hidden Crack in Graphite Electrodes
In Reply to MM Damani at 00:00 Feb-12-2003 (Opening).

You can use 410D model from Sonatest UK. Since you wanted to check Porosity etc., you can use Air Coupled System for this application as it can give a C Scan image and porosity, other mentioned defects.

If you are in India, you can contact me for further details. www.anuconsultants.net

 
 Reply 
 
Dustin
Dustin
12:42 Aug-11-2017
Re: Hidden Crack in Graphite Electrodes
In Reply to MM Damani at 00:00 Feb-12-2003 (Opening).

I had purchased Graphite Electrode RP 350 mm * 1800 MM with 4 TPI nipple plus 3% wherein the there is a serious quality problem. During operation of the electrodes in electric arc furnace, several times slipage happened. Can you kindly know me the technical deficiency in graphite electrodes due to which such slipage is happening.

 
 Reply 
 

Product Spotlight

UCI Hardness Tester NOVOTEST T-U2

UCI hardness tester NOVOTEST T-U2 is is used for non-destructive hardness testing of: metals and
...
alloys by scales of hardness: Rockwell (HRC), Brinell (HB), Vickers (HV); non-ferrous metals, alloys of iron etc., and using five additional scales for calibration; with tensile strength (Rm) scale determines the tensile strength of carbon steel pearlitic products by automatic recalculation from Brinell (HB) hardness scale.
>

YXLON Cougar EVO

Scalable small footprint X-ray inspection systems for assembly and laboratory applications. The
...
YXLON Cougar EVO series was designed to provide the "best-in- class" inspection solutions for SMT, semiconductor, and laboratory assembly applications, while maintaining a small system footprint for maximum convenience. With optimized software and hardware, these systems produce higher quality and more consistent results than other electronics inspection systems currently on the market.
>

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.
>

Ultrasonic tomograph for imaging of concrete structures А1040 MIRA

Applicable for concrete inspection allowing imaging of the internal structure of objects from conc
...
rete, reinforced concrete, different stones. The operation applies pulse-echo technique at one-side access to the object. The instrument is feasible for concrete inspection for searching conduct ducts, conduits, detection of foreign inclusions, holes, honeycombing, cracks and other concrete defects.
>

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