METHOD OF FORMING BUTT WELDS IN PIPES Russian patent published in 2007 - IPC B23K28/02 B23K31/02 B23K37/08 

FIELD: mechanical engineering; plastic metal working.

SUBSTANCE: invention relates to processes for forming butt weld studs. Proposed method includes preparatory operations carried out on members to be welded, assembling of members with provision of clearance between end faces, fitting filler material in form of wire into clearance, forming of inner weld from filler material and pipe material by argon-arc welding with nonconsumable electrode and then forming of outer weld with convexity. After welding, at temperature of heating of butt joined members, hot plastic deformation is done by radial upsetting by radial displacement of deforming segments with ring grooves. First only metal of filler wire of convexity is subjected to plastic metal working with partial filling of free spaces of ring grooves of deforming segments and forming of zone of difficult deformation and at further radial displacement of deforming segments, formed zone of difficult deformation is introduced into weld and its deformation is carried out. At final stage, combined deformation of weld and near-weld zones is done on hardened steel mandrel by building three-axis nonuniform compression of weld. Mandrel is placed in location of weld in space of members to be connected before hot plastic metal working.

EFFECT: improved quality of welds and near-weld zones.

6 dwg