PURPOSE:
The Ukrainian Institute has developed a new method for welding rails, called automatic electric arc welding of rails in a bathtub using a nozzle that melts.
DESCRIPTION:
Automatic electric arc welding of rails in a bathtub using a nozzle that melts is used in the construction, reconstruction and repair of tracks in the systems of light rail transport – subway, tram, high-speed tram, city railroad, including continuous welded high-speed lines with temperature-stressed rail tracks, railway tracks of industrial transport (access and cargo), crane tracks, as well as for welding rail joints within the turnouts. The developed method is primarily intended for operational repair work. A distinctive feature of the developed method is the use of a self-shielded flux-cored wire, which is fed through a longitudinal channel in a special flat fusible mouthpiece, which allows welding with a gap in the joint of 12-16 mm, and in some cases up to 24 mm. The proposed welding method, is a further development of the electric arc welding bath, thanks to the mechanization of the process, allows to increase the productivity of work by 2-3 times and at the same time significantly improve the quality indicators of welded joints, while maintaining high mobility and versatility of the equipment. In most cases, no preheating is performed before welding – only at temperatures below 0 ° C it is necessary to heat the joints to 250-300 ° C, while welding can be carried out at ambient temperatures down to -5 ° C Welding equipment is portable and, thanks to the variable, forms equipment, easily reconfigurable for welding of rails of various standard sizes. The average machine time for welding a joint of P65 rails is 15-20 minutes, which allows a combined team of 4 people (two welders and two road workers) to achieve a productivity of up to 15 joints per shift.
TECHNICAL CHARACTERISTICS:
The developed special welding consumables and welding technology provide sufficiently high indicators of the mechanical properties of welded joints. Mechanical properties of the welded joint of R65 rails: seam metal hardness – 260-320 HB; the ultimate strength of the weld is 800-900 MPa. Test results for static bending: breaking load – 1500-1650 kN; deflection – 16-22 mm.
ADVANTAGES:
Higher and stable quality of welded joints in comparison with manual arc welding and aluminothermic welding; high productivity – up to 15 joints per shift; no shielding gas or flux needed; no need for heating and heat treatment of the joint; low power consumption – power consumption up to 12 kVA; equipment is easily reconfigured for welding rails of various standard sizes; high mobility, which is especially important when carrying out repair work.
RECOMMENDED FIELD OF APPLICATION:
Construction, reconstruction, repair works of track in light rail transport systems.
RESULTS OF THE RESEARCH:
Special welding materials and technology provide welding of rails with a gap in the joint from 12 to 24 mm, allow 2-3 times to increase work productivity and at the same time significantly improve the quality indicators of welded joints.
STAGE OF THE DEVELOPMENT READINESS:
The project has already started.
TRANSFER OPPORTUNITY:
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- Technical cooperation.
- License agreement.
- Commercial agreement with technical assistance.
NOVELTY:
1 patent of Ukraine.
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