Building and Operating Experience of Spherical-Tank LNG Carriers

1977 ◽  
Vol 14 (02) ◽  
pp. 158-174
Author(s):  
James L. Howard ◽  
Rolf S. Kvamsdal ◽  
Kjeld Naesheim
Keyword(s):  
Nondestructive Testing ◽  
Operating Experience ◽  
Temperature Measurements ◽  
Nickel Steel ◽  
Critical Areas ◽  
Percent Nickel ◽  
Analytical Studies ◽  
Spherical Tank

A summary of the analytical and experimental bases of the spherical-tank LNG carriers of the Kvaerner-Moss design is given. Primary attention is paid to a complete description of the experience from building spherical tanks in both 9 percent nickel steel and aluminum, including such critical areas as welding, nondestructive testing, maintenance of tolerances, and repairs of defects. The results of stress and temperature measurements made on the cargo tanks under test are compared with earlier predictions from analytical studies. Operating experience with the cargo system is reported.

Pre-grading of spruce logs containing frozen and unfrozen water by means of frequency-based nondestructive testing (NDT)

Holzforschung ◽  
2016 ◽  
Vol 70 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Julia K. Denzler ◽  
Andreas Weidenhiller
Keyword(s):  
Nondestructive Testing ◽  
Moisture Content ◽  
Industrial Application ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
The State ◽  
Temperature Measurements ◽  
Unfrozen Water ◽  
State Of Matter

AbstractThe possibility for pre-grading of logs throughout the year has been evaluated based on dynamic modulus of elasticity (MOEdynor simplifiedEdyn) by means of frequency-based nondestructive testing (NDTfreq). The challenge is thatEdynis variable in the frozen, partly frozen, and unfrozen states of logs (state of matter). In the unfrozen state, NDTfreqis reliable if the moisture content does not fall below fiber saturation. The state of the matter was tested via temperature measurements of air and log by means of an infrared technique and sensors, and information was evaluated from NDTfreq. The temperature measurements proved to be inefficient for industrial application because of unreliable data and long measurement times, whereas the NDTfreqmeasurements allowed the determination of meaningful damping factors. A sufficient level of predictability for more than 60% of the measurements was found. The log measurements in the partly frozen state are inconclusive becauseEdyndata fluctuate in the presence of both liquid and frozen water. For the completely frozen logs, a correction is introduced as a precaution that avoids an overestimation ofEdynin the unfrozen state.

scholarly journals Experimental Study on Bead on Plate (BOP) Welding of 6 mm Thick 9% Nickel Steel by Fiber Laser Welding

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7699
Author(s):  
Jaewoong Kim ◽  
Changmin Pyo ◽  
Yonghyun Kim ◽  
Sungwook Kang ◽  
Taegon Yeo ◽  
...  
Keyword(s):  
Experimental Study ◽  
Fiber Laser ◽  
Filler Metal ◽  
Nickel Steel ◽  
Optimal Conditions ◽  
Fiber Laser Welding ◽  
Butt Welding ◽  
Percent Nickel ◽  
Lng Fuel ◽  
Welding Position

Nine percent nickel steel has excellent properties in a cryogenic environment, so it has recently been used as a tank material for most LNG fuel-powered ships. However, 9% nickel steel causes arc deflection due to its tendency of magnetization during manual FCAW welding and the currently used filler metal is 10–25 times more expensive as a base metal compared to other materials, depending on manufacturers. Furthermore, the properties of its filler metal cause limitation in the welding position. To overcome these disadvantages, in this study, the tendency of penetration shape was analyzed through a fiber laser Bead on Plate (BOP) welding for 9% nickel steel with a thickness of 6 mm and a range of welding conditions for 1-pass laser butt welding of 6 mm thick 9% nickel steel with I-Groove were derived. Through this study, basic data capable of deriving optimal conditions for laser butt welding of 9% nickel steel with a thickness of 6 mm were obtained.

A New Alloy Steel for Marine Cryogenic Applications

1972 ◽  
Vol 9 (03) ◽  
pp. 297-301
Author(s):  
G. E. Kampschaefer ◽  
F. E. Havens ◽  
D. A. Sarno
Keyword(s):  
Heat Treatment ◽  
Alloy Steel ◽  
High Strength ◽  
Notch Toughness ◽  
Nickel Steel ◽  
Percent Nickel ◽  
Joint Properties ◽  
Filler Metals

The authors describe a new five percent nickel steel which is currently being considered for marine cryogenic applications involving the transport of liquefied ethylene and methane. The alloy combined with a unique heat treatment develops both high strength and good notch toughness properties at temperatures below —150 F. Results of weld tests are presented which show that filler metals and processes used for nine percent nickel steel produce adequate joint properties with this new economical alloy.

Fatigue and Fracture Toughness Properties of 9 Percent Nickel Steel at LNG Temperatures

1973 ◽  
Vol 95 (4) ◽  
pp. 1069-1075 ◽  
Author(s):  
D. A. Sarno ◽  
D. E. McCabe ◽  
T. G. Heberling
Keyword(s):  
Fracture Toughness ◽  
Arc Welding ◽  
Base Plate ◽  
Nickel Steel ◽  
Rotating Beam ◽  
Shielded Metal Arc Welding ◽  
Percent Nickel ◽  
Metal Arc Welding ◽  
Fatigue And Fracture ◽  
Welding Processes

9 percent nickel steel has been evaluated for use in a semimembrane LNG containment design. Fatigue and fracture toughness properties of 1/4 in. thick base plate and weldments have been determined at cryogenic temperatures. Results of rotating beam fatigue, stress intensity (Kc) and fatigue crack growth rate (da/dN versus ΔK) studies are presented. Data predict that 9 percent nickel steel, fabricated with the gas metal arc and shielded metal arc welding processes, may be successfully applied as the primary tank material for this LNG design.

LNG Marine Carrier Construction

1972 ◽  
Vol 9 (03) ◽  
pp. 281-291
Author(s):  
James L. Howard
Keyword(s):  
Design Analysis ◽  
Nickel Steel ◽  
Percent Nickel ◽  
Containment System ◽  
Analytical Work ◽  
Materials Research

The author describes the several concepts around which the existing marine LNG containment designs are formulated. The Kvaerner-Moss spherical containment system without secondary barrier is discussed in some detail. The design analysis of that system is presented in a step-by-step fashion as actually performed, along with descriptions of tank materials research and structural experiments which supplement the analytical work. The fabrication sequence of the spheres is discussed, and the welding procedures used for both aluminum and 9 percent nickel steel are included.

Studies on Nine Percent Nickel Steel for Liquefied Natural Gas Carriers

2009 ◽  
pp. 205-205-33 ◽  
Author(s):  
T Sakai ◽  
H Takashima ◽  
K Tanaka ◽  
H Matsumae ◽  
H Yajima
Keyword(s):  
Natural Gas ◽  
Liquefied Natural Gas ◽  
Nickel Steel ◽  
Percent Nickel

“High Resolution High Voltage Electron Microscopy”

1968 ◽  
Vol 26 ◽  
pp. 326-327
Author(s):  
Benjamin M. Siegel
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Voltage ◽  
Full Potential ◽  
Contrast Imaging ◽  
High Voltage Electron Microscopy ◽  
Low Contrast ◽  
Voltage Electron ◽  
Critical Areas ◽  
High Voltage Electron

The potential advantages of high voltage electron microscopy for extending the limits of resolution and contrast in imaging low contrast objects, such as biomolecular specimens, is very great. The results of computations will be presented showing that at accelerating voltages of 500-1000 kV it should be possible to achieve spacial resolutions of 1 to 1.5 Å and using phase contrast imaging achieve adequate image contrast to observe single atoms of low atomic number.The practical problems associated with the design and utilization of the high voltage instrument are, optimistically, within the range of competence of the state of the art. However, there are some extremely important and critical areas to be systematically investigated before we have achieved this competence. The basic electron optics of the column required is well understood, but before the full potential of an instrument capable of resolutions of better than 1.5 Å are realized some very careful development work will be required. Of great importance for the actual achievement of high resolution with a high voltage electron microscope is the fundamental limitation set by the characteristics of the high voltage electron beam that can be obtained from the accelerator column.

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