Ultrasonic Thickness Testing

2018 ◽  
Author(s):  
Keyword(s):  
Thickness Testing ◽  
Ultrasonic Thickness

Digester thinning: Erosion-corrosion of internal flow channel headers

TAPPI Journal ◽  
2014 ◽  
Vol 13 (8) ◽  
pp. 9-15
Author(s):  
GREG A. BUSBY ◽  
PETER W. HART
Keyword(s):  
Black Liquor ◽  
Electrochemical Corrosion ◽  
Internal Flow ◽  
Flow Channel ◽  
Corrosion Rates ◽  
Flow Channels ◽  
Erosion Corrosion ◽  
Severe Erosion ◽  
Thickness Testing ◽  
Ultrasonic Thickness

A softwood continuous digester has experienced severe erosion-corrosion of the shell wall inside the internal flow channel headers of the extraction and modified continuous cooking (MCC) zones. Although erosioncorrosion is a common form, it is not typically looked for inside digester flow channels. The worst damage was located where high velocity liquor exits the screen orifices and enters the collection headers. With erosion-corrosion rates as high as 200 m/year, the damage has effectively reduced the wall thickness almost by half in the worst areas. Also affected were the horizontal backing rings that form the bottom of the flow channels. An API-579/ASME FFS-1 Part 5, Level 2 analysis was performed to allow the mill to continue operating the digester until the next scheduled outage. Owner-users are encouraged to inspect these locations in their digesters to ensure that erosion-corrosion has not caused accelerated and/or unexpected shell thinning. The internal flow channels represent locations that are not readily accessible for internal visual inspection without removal of the flow channel header cover plates and removal of the residual black liquor typically retained in these flow channels. External, on-stream ultrasonic thickness testing (UT) at the proper collection header elevations has been determined to be an effective way to detect the presence of this erosion-corrosion phenomena. Also discussed are considerations to make on-stream UT as accurate as possible. Corrosion rates determined via electrochemical corrosion probe monitoring have correlated very well with the corrosion rates determined by on-stream UT data.

2D Color-Intensity Representation of Ultrasonic Thickness Gauge Measurements

2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong
Keyword(s):  
Cost Effective ◽  
The Other ◽  
Thickness Gauge ◽  
Color Intensity ◽  
Digital Readout ◽  
Flat Surfaces ◽  
Video Cameras ◽  
Wide Range ◽  
Cost Effective Alternative ◽  
Ultrasonic Thickness

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.

Studi Laju Korosi Internal Pipa Baja Api 5L Grade B Berdasarkan Metode Pengukuran Metal Loss Dengan Ultrasonic Dan Polarisasi Resistance Dengan Variasi Konsentrasi Klorida

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Supriyadi Supriyadi
Keyword(s):  
Analysis Of Variance ◽  
Metal Loss ◽  
Thickness Meter ◽  
Ultrasonic Thickness

Pipa  penyalur  minyak  umumnya  menggunakan  material  baja  karbon.  Salah  satu  masalah  besar  dalam penggunaan material tersebut yang berkaitan dengan korosi yaitu terjadinya kebocoran akibat adanya pengaruh konsentrasi ion klorida yang terlarut dalam media air sehingga lingkungan bersifat korosif (asam). Oleh karena itu sebagai upaya untuk mengatasi masalah tersebut perlu diketahui besaran laju korosi material baja karbon tersebut. Dalam penelitian ini dilakukan perbandingan antara laju korosi yang diperoleh dari metode pengujian linear polarisasi resistance dan pengukuran metal loss dengan peralatan ultrasonic thickness meter. Output dari kedua metode tersebut selanjutnya diperoleh hubungan laju korosi melalui analysis of variance dengan menggunakan software. Studi pengaruh kadar klorida dilakukan untuk mengetahui korosi internal pipa baja karbon API 5L Grade B yang digunakan sebagai pipa penyalur minyak di lapangan. Metode pengujian polarisasi resistance dilakukan dalam media larutan air formasi NaCl 1%, 2% dan 3.5%. Laju korosi internal pipa baja karbon API 5L Grade B cenderung meningkat seiring dengan meningkatnya konsentrasi klorida dalam media larutan. Penelitian ini juga menunjukkan bahwa pipa baja karbon API 5L Grade B memiliki ketahanan korosi yang cukup pada fluida dengan konsentrasi klorida 1%, 2% dan 3.5%.

scholarly journals Continuous ultrasonic thickness measurement technology

2017 ◽  
Vol 13 ◽  
pp. 01026 ◽  
Author(s):  
Vitaliy Pronin ◽  
Petr Shkatov ◽  
Anna Sandulyak ◽  
Haci Mehmet Baskonus
Keyword(s):  
Thickness Measurement ◽  
Measurement Technology ◽  
Ultrasonic Thickness Measurement ◽  
Ultrasonic Thickness
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