In this article ESAB describes some applications in which overlaying weld metal is a cost-effective alternative to replacing worn parts with new components.
It is a fact of life that heavy machinery wears out. Replacing worn components with new ones is not always economical, but welding and weld overlay techniques can be used to renovate steel parts in almost every industrial sector.
Weld overlay is a highly cost-effective way of creating wear-resistant layers on machinery; components such as digging tools, shovel teeth, tracks, rails, wheels and rolls can all benefit.
In the most extreme environments, digger buckets, crushers and screens may need to be refurbished monthly, so replacement with new parts is seldom feasible. One good example of the advantage of refurbishment over replacement is the use of twin-wire submerged arc welding with flux-cored wires on pistons for large diesel engines.
Larger pistons with diameters of 700mm or more can be refurbished with a productivity gain of 25 per cent without any increase in production costs. Piston ring grooves wear continuously due to the motion of the ring in the groove, and the piston head surface also wears, largely because of the extreme thermal conditions inside the cylinder.
In a demonstration project carried out by welding specialist ESAB and a partner, two layers of hard surfacing, with OK Flux 10.80, achieved a surface hardness of 350HB (~37HRC). Flux-cored wires applied in the twin-wire mode allowed the replacement of solid wire with basic flux-cored wire (two 2.4mm wires instead of single 4mm solid wire).
The wire selected for this demonstration project was OK Tubrod 15.21S (containing 0.5 per cent molybdenum), which is highly resistant to cracking. Thanks to this technique, the deposition rate was increased by 50 per cent, there were fewer weld defects and a more consistent bead deposit was achieved.
ESAB's hardfacing solid wires (OK Autrod 13.90, OK Autrod 13.89 and OK Autrod 13.91) are commonly used for repair and maintenance in such industries as railways, mining, quarrying, agriculture and scrap yards.
For more information on the company's established and new products, call ESAB Publicity on +44 (0)800 3893152 or email .