ROLLING STOCK AND TRACTION
The fastest welding for the fastest trains
The installation and commissioning of a 30m x 4m gantry ‘Powerstir’ Friction Stir Welder (FSW) by UK-based PTG Heavy Industries – in a joint project with the China Friction Stir Welding Centre – didn’t just represent a fi rst for China and for PTG. Neil Jones, group business development director, explains more.
T
he Powerstir machine also played its part in a world fi rst, being used in the manufacture
of railway car bodies similar to those used in China’s record-breaking ‘Harmony’ high-speed train. In producing the railway car bodies, another record was also broken, with the PTG Powerstir machine producing the longest-ever single FSW railway panel weld in China – at over 15 metres in length.
The FSW process More than fi ve times faster
In simple terms, Friction Stir Welding is a ‘solid state’ welding process that joins materials by plasticising and consolidating the material around the joint line.
A rotating pin generates heat that creates a
With speeds of up to 2000 mm/min, FSW is more than fi ve times faster than conventional welding methods.
It is also not affected by the disadvantages of
Most importantly, FSW produces vastly superior joint strength and weld appearance with no post-weld grinding.
FOR MORE INFORMATION
T: +44 (0)1422 379 222 W:
www.ptgheavyindustries.com
tubular shaft of plasticised material around the pin. Then pressure, provided by forward motion and the downward force of the tool shoulder, forces the plasticised material to the back of the pin, cooling and consolidating the material.
No melting takes place and the fi nal result is a fi ne-grained, hot-worked weld with no entrapped oxides or porosity.
conventional welding, namely weakening in the heat affected zone, high-energy consumption, distortion requiring secondary operations, the requirement for two operators per weld head, no record of weld data, fume extraction and environmental hazards.
The FSW process, by comparison, gives low distortion even in long welds and excellent mechanical properties.
rail technology magazine Feb/Mar 13 | 51
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