Crane and railway rails are made from steel grades that are not easily welded using conventional methods. For site welding of crane rails the most common techniques are Puddle Arc (sometimes called Enclosed Arc), Thermit and Flash Butt Welding. Gantrail is recognised around the world as the leading company in the field of crane rail welding.
Welding Crane Rails
Cranes operate best when the rails on to which they run are welded into continuous lengths. However rails are difficult to weld as they
Have high carbon content to give them wear resistance
Have a high carbon equivalent and must be welded using special techniques
Are considered to have a large and awkward section for welding
Rail Welding Methods
Rail welding methods ideally allow:
Rails to be cut square and not bevelled
High preheat to cater for the steel composition
High weld metal deposition rates
Acceptable defect level for the fracture resistance of the steel
Puddle arc, Thermit and Flash Butt Welding meet these criteria. Although Flash is not suitable for most large section European rails.
Puddle arc is widely used throughout the world for welding crane rails. Gantrail employ skilled technicians who can do this work or can train other operatives. In this method the two rail ends to be joined are cut square, placed about 15 mm apart, preheated and then welded using special stick electrodes.
Test Puddle Arc Weld before Head Grinding
Thermit welding uses a refractory mould around the two square cut rails ends. After preheating the rail ends the gap is filled from a crucible containing a chemically heated charge of molten steel.
Both methods require the careful following of procedures by skilled operatives.
Flash Butt Welding is commonly used for welding railway rail in steel mills before shipment. It is sometimes used for site welding crane rails. It requires thousands of amps current and hence heavy expensive equipment. The rail ends are heated by the current passing between them. When hot enough they are forged together.
