IMPROVING IN-TRACK RAIL WELDING Rainer Wenty, Plasser & Theurer Vienna, Austria
Continuous welded rail a success story • Continuous welded rail - standard practice on todays railways • Axle loads in excess of 30 tonnes and speeds up to 575 km/h (French world record) would not be possible on traditional jointed track • such extreme loads and speeds pose a great challenge for welded joints • durability of welded rail joints still needs improvement • reported e.g. at Heavy Haul Congresses in India[1] [1]
IHHA 10th International Conference in New Delhi, February 4th-6th 2013
Mobile Flash Butt Welding the Start • 1960ties: Paton Institute in the Ukraine starts the development of a mobile flash-butt welding unit • 1973 K 355 of Plasser & Theurer at Austrian Federal Railways (OEBB)
K 355 PT first Machine at Austrian Railways
Further Developments • Integration of trimming unit into the welding head • Change the dimensions of the welding head so that the trailing edge of the rail foot is lower than the bottom of the jaws • Rail/road machines • Integration of an automatic high capacity rail pulling device into the mobile welding machine • Control of the operation by a microprocessor • Computer-controlled recording and analysing system
The Challange of High Axle Loads AAR Test Center (TTCI) Study 1988-1990 Table 1: Failure rates of aluminothermic welding
Failure rate Axle Load
Traffic load Outside rail
Inside rail
33 t
65 Mio tons
29%
0%
39 t
65 Mio tons
67%
13%
39 t
82 Mio tons
83% in 5° curve, 92% in 6° curve
-
39 t
144 Mio tons
-
75%
Table 2: Failure rates of stationary flash butt welding Failure rate Axle Load
Traffic load
Curvature Outside rail
Inside rail
33 t
160 Mio tons
5°
3%
8%
33 t
160 Mio tons
6°
2%
2%
39 t
145 Mio tons
5°
5%
9%
39 t
145 Mio tons
6°
-
4%
Mobile flash butt welding: Due to the small number of welds no statistical statements could be made, however clear positive trends were detectable
A New Welding Machine – why? • High demands on welded joints • Europe: new standard EN 14587-2 (2009) • Heavy Haul: weld defects • Improved alignement of welded joints • Improved thermal process • Head hardened rails • High alloy rails • Improved butting process • Uniform quality without human influence • Increased work performance • Execution of closure welds
Welding head designed by Plasser • Expierience in flash butt welding since 1973 • 120 Machines • Integration of expierience and improvements in this 40 years in a complete new design
The new APT 1500 Robot
Trafos
Air amplifier nozzles
Auxiliary lifting clamp
Clamping cylinders
Power supply line
Shearing device Pulling cylinder 200mm/1500kN Rail alignment
Head Parameters • • • •
Fully integrated automated welding process Integrated auxiliary lifting clamps Automatic alignment vertical and horizontal Automatic measuring device for alignment and level • DC-Current head – rectified 1000 Hz AC • Controlled cooling process by • Integrated temperature measurement • Integrated controlled post heat • Integrated air quenching nozzles
Head Parameters • Integrated pulse welding with reduced rail consumption • Specific clamping jaw – no removal of rail branding necessary
Production sign
Head Parameters • Integrated pulse welding with reduced rail consumption • Specific clamping jaw – no removal of rail branding necessary • Certified already by leading European bodies • Pull-in range 200 mm (8“) • Max. pulling force 150 – 200 tons • Enables closure welds
Closure welds
Welding Robot
WELD QUALITY
Weld Quality
HARDNESS
Train passing bad joint
Hardness Test
Sec
Time Min
Temperature in ° C
Sec
Time Min
Temperature in ° C
Weld Quality
STRENGTH
Bending Test
Bending/ breaking force standard welding procedure
Bending/ breaking force new pulse welding procedure
Weld Quality
CONTROLLED BUTTING PROCESS
Weld Quality
CERTIFICATION
Welding Robot
MACHINE IN ACTION
Welding process
Variants • Track bound machine • Road mobile machine • Container
Summary • Premium Rail Welding • Premium metallurgic quality • Premium hardness pattern • Premium weld geometry • Premium output • Premium operating comfort
Thank you!
Rainer Wenty Plasser & Theurer A-1010 Wien, Johannesgasse 3 Tel.: +43 (0) 1 515 72-0 Fax: +43 (0) 1 513 18 01 E-Mail:
[email protected] www.plassertheurer.com
Illustrations and descriptions may contain optional equipment. We reserve the right to make alterations in line with further technical developments.
