The production flow of LASW large-caliber thick-wall straight seam double-sided submerged arc welding steel pipes is: firstly mill the edge of medium plate and put it into pressure forming device, form it into a circle according to the mode of J.C.O, and then preweld it after seam butting by seam butting device and then start the double-sided submerged arc welding. After nondestructive detection one by one, the products could be used as large-caliber liquid conveying pipe such as petroleum, natural gas and others. LSAW steel pipe is produced by adopting the internationally advanced technology which has been introduced in recent days. The production lines could provide the steel pipes with the diameter of over 610mm and wall thickness of over 15mm that could not be manufactured by ERW steel pipe production line. The LSAW steel pipes could be 2150mm in max. caliber and 30mm in max. wall thickness. Take the western gas eastern transportation project as example, the project will need 964 thousand tons of LSAW pipes, only 141.6 thousand tons of which could be supplied in China, and the rest will be imported. It could be seen that the kind of steel pipes is under supply in China, which shows its strong market needs.

    Equipment Introduction: The large-caliber straight seam double-sided submerged arc welding steel pipes adopt the most advanced hydraulic bending process in China. The bending machine is of double linked structure, which could process the max. length of 16m with the max. pressure of 1600tons. The single machine could be up to 400tons. So, the bending machine could be able to process the ordinary and the special steel pipes with the diameter of 325-2150mm and wall thickness of 6-30mm. The products could be up to the standard requirements of USA Petroleum Association through many processes including bending, seam butting, internal welding, external welding, straightening, and head flattening etc. So, the products are the optimal choice for the large pipe engineering, water or gas transportation project, urban pipe network construction. Till now, the State Project of Western Gas Eastern Transportation has used 20 tons of pipes of the kind, most of which is imported. Due to low market competition and large demand, the pipes will have good market in China.