HARDFACING VS WELDING
HARDFACING belongs to welding and is a KIND of welding.
As an economical and rapid process for surface modification of materials, hardfacing is more and more widely used in the manufacture and repair of parts in various industrial sectors. In order to give full play to the function of surfacing layer,it is expected that the hardfacing welding method should have less base metal dilution, higher deposition speed and better surfacing layer properties, i. e. high quality, high efficiency and low dilution.
PLASMA WELDING VS LASER WELDING
PLASMA IS ARC welding, laser is photothermal welding, plasma are generally more efficient than laser, effective power is also high. But the extreme field laser is more suitable.
Laser welding is a high efficient and precise welding method which uses high energy density laser beam as heat source to melt the workpiece and form a special molten pool for welding thin-walled materials and low-speed Welding. Laser cladding is a method of adding cladding material on the surface of substrate and using high energy density laser beam to make it melt together with the thin layer on the surface of substrate.
HARDFACING WELDING VS SPRAY WELDING
Hardfacing welding is applied to the repair of thick base material, such as coal mill, cement mill, roller repair.
Spray welding to the base material is thinner or not suitable for surfacing of the repair or protection of components, such as high-pressure Boiler Wall Spray, Fan Blade spray, and so on. Spray welding is to reheat the preheated self-soluble alloy powder coating to 1000 ~ 1300 °C, so that the particles melt, slagging float to the surface of the coating, the borides and silicide formed in the coating, so that the particles and the substrate surface to achieve a good combination. The final deposit is a compact metallic crystalline structure and forms a metallurgical bonding layer of about 0.05 ~ 0.1 mm with a bonding strength of about 400 MPA, good impact resistance, wear resistance, corrosion resistance and mirror-like appearance.
As an economical and rapid process for surface modification of materials, surfacing is more and more widely used in the manufacture and repair of parts in various industrial sectors. In order to give full play to the function of surfacing layer,it is expected that the surfacing welding method should have less base metal dilution, higher deposition speed and better surfacing layer properties.
OPEN ARC HARDFACING VS SUBMERGED ARC WELDING
OPEN-ARC SURFACING HAS TWO PROCESSES:
1.The use of Gas metal arc welding wire requires the use of a flat characteristic output Gas metal arc welding machine, nitrogen dioxide or its mixture of shielding gas, the use of wire diameter not exceeding 1.6 mm, ARC light and spatter when welding, welding speed is slower; the equipment is relatively simple It’s cheap.
2.using self-shielded flux-cored wire, need to use flat characteristic output welding machine, no protective gas, wire
diameter is not more than 2.8 mm, arc light and splash when welding, welding speed is faster, equipment is more complex, more expensive.
Submerged ARC hardfacing process:
Using automatic welding machine with flat or falling characteristic output, no protective gas is needed, but submerged arc flux is needed (match with welding wire) , the diameter of welding wire is up to 5mm, and multi-wire simultaneous welding can be carried out. There is no arc light and spatter when welding, the welding speed is very fast and the molding is very good, but the equipment is complex and the price is high.
LASER WELDING VS LASER CLADDING
Laser welding is a high efficient and precise welding method which uses high energy density laser beam as heat source to melt the workpiece and form a special molten pool for welding thin-walled materials and low-speed Welding. Laser cladding is a method of adding cladding material on the surface of substrate and using high energy density laser beam to make it melt together with the thin layer on the surface of substrate.
