Weld hardfacings are typically between 1.5 and about 20 mm thick. They can be applied using a variety of welding processes including manual metal arc (MMA) gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), submerged arc welding (SAW), flux cored arc welding (FCAW), plasma transferred arc welding (PTAW) and laser deposition.
Weld hardfacing materials tend to be hard, brittle and prone to cracking. Therefore, welding practices and weld process parameters (including the use of buttering layers, preheats, interpass temperatures and post-weld heat treatments) must be carefully optimised. The integrity of the hardfaced layer and adequate toughness of the heat-affected zone (HAZ) must be ensured whilst simultaneously maintaining the substrate material properties.
For complex, large or geometrically constrained components, or for specific base materials such as duplex steels, tool steels, high-carbon steels or martensitic steels, this can be a challenging task requiring an in-depth understanding of the metallurgy of the substrate as well as the hardfacing material.
Another important consideration is the dilution of the hardfacing layer by the substrate material and the effect of that on both the wear and corrosion resistance of the hardfacing.
With world class expertise in all welding processes, as well as metallurgists with knowledge of hardfacing alloys and the welding of 'difficult' steels, TWI is able to put together a team of truly independent specialists to advise on any hardfacing query. We can assist you with materials selection, failure analysis and processing advice.
We can also advise on the weld joining of clad or hardfaced plates or pipes.