METHOD OF WELDING CIRCULAR PIPE JOINTS Russian patent published in 2009 - IPC B23K28/02 B23K33/00 B23K31/02 B23K101/06 

FIELD: welding works.

SUBSTANCE: present invention relates to methods of welding circular pipe joints and can be used in making welded pipes in electrical welding machines, as well as in constructing main pipelines, commercial and marine pipelines in the oil and gas industry. The welding method involves preparation with blunting of the ends of welded pipes with sections with uniform cross section of thickness d depending on the material and thickness s of the wall of the pipe in accordance with the ratio d/s=0.15-0.6 and length , where d is the thickness of the prepared part, mm, s is the thickness of welded pipes, mm, t is the value for filling up when welding the remaining prepared part, mm, Δ is the maximum specified value of the cutting angle of the ends of the pipe, mm, l_fu is the total length of fused sections of the pipe during electro-contact welding of the primary seam, mm, l_s is the total length of set sections of the of the pipe during electro-contact welding of the primary seam, mm, which is equal to the thickness of molten metal on two ends directly before setting. The edges of the section with alternating cross section are prepared at an angle α=0-30°. Assembling of joints, centering, welding the primary seam through electro-contact flash welding and filling of the remaining part for preparation for laser welding at temperature of the primary seam welded using electro-contact welding are done.

EFFECT: invention increases output and quality of the welded joint.

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