E.O. Paton Electric Welding Institute, Kyiv, Ukraine FLASH-BUTT WELDING FOR COMPRESSED NATURAL GAS (SNG) TRANSPORTATION AND STORAGE Ihor Ziakhor, Ph. D.

The Coselle is a unique system, invented in Canada, for Compressed Natural Gas (CNG) transportation and storage in coil of small diameter pipe. A single Coselle carries about 3.0 million standard cubic feet (mmscf) of natural gas. Numerous Coselles with CNG are contained within the specially-designed ship.

Potential markets for CNG concept What is CNG / LNG

Design and capacity of Coselle system Each coselle consists of about 17,350 meters of 168 mm diameter pipe of high strength X70 steel The size of a Coselle may range from 15 to 20 meters in diameter and 2.5 to 4.5 meters in height, and it may weigh about 550 tones. Fully Framed Coselle (20m exterior Diameter)

 One of the main problems is to manufacture coiled pipe structures using the most appropriate technology The first problem is reliable method of single X70 steel pipes connection (welding) into long pipe section The second problem is long pipe section winding with minimal ovalization 1 - to weld 2 - to wind

Innovative Aspect E.O. Paton Welding Institute proposed to Sea NG, Canada, the inventor of Coselle technology, to use Flash Butt Welding (FBW) for pipe connection Experimental evaluation of FBW applied to coiled pipe structures manufacture has shown technical advantages over standard welding methods

What’s the problem Flash butt welding (FBW) is the process where the parts to be welded are heated to required temperature by passing of electric current and pressed to each other to form a welded joint FBW is applied for welding steel pipes, rails, and other rolled stocks, parts of light metal alloys, e.g. aluminium-base and titanium-base alloys However, FBW performed with the available equipment is limited in capabilities due to the level of technical characteristics of existing welding machines, mainly electronic and hydraulic control systems.

Development of a new generation of the FBW technology and equipment to address the following tasks: raising efficiency of the process through building fast-response actuating mechanisms and computerized system to control the welding process; raising productivity and ensuring a specified level of mechanical properties of welded joints through intensification of the thermal-deformation cycle of welding; computerization of inspection and diagnostics of quality of welded joints; improving environmental characteristics of the process (substantial decrease in harmful emissions into the atmosphere)

during welding of pipes Stage of Development: The experimental equipment prototype and several batches of welded pipes are available. Modernized K584M machine during welding of pipes for Coselle manufacture Welded pipe specimen after bending

Main Advantages of Flash-Butt Welding (FBW) applied to manufacturing coselles. This solution will allow to strengthen mechanical properties of welded joints, in particular cyclic weld strength, to increase productivity of winding pipes, to enhance safety and reliability of Coselle carries Plots of fatigue resistance of welded joints in X70 (1) and X56 (2) pipes

Contact Details Dr. Valerij Kryvenko Phone: (380 044 ) 524-7304; Fax: (380 044 ) 227-6329; 271-2328 E-mail: elweld@viaduk.net, zyakhor@paton.kiev.ua E.O. Paton Electric Welding Institute, Kyiv Address: 03680, Ukraine, Kyiv, 11, Bozhenko str.