Plasma Transfer Arc Equipment - PTA
SAINT-GOBAIN Coating Solutions designs and manufactures Plasma Transferred Arc (P.T.A) welding equipment for hardfacing applications. PTA overlays offer a wide range of solutions to solve severe abrasion & wear problems for many industries such as oil drilling, ore mining, power generation, plastic extrusion, foundries, steel making, wood industry, petrochemical.
PTA-PHE - a valuable and versatile tool for hardfacing
The Saint-Gobain PTA-PHE equipment is a 2 in 1 equipment which allows the user to produce thick overlays at high welding rates as well as thin overlays with low distortion and low dilution rates.
PTA-PHE produces overlays for corrosion resistance, oxidation resistance, wear resistance or abrasion resistance.
A wide range of commercial metal alloys are weldable with our PTA-PHE: nickel alloys, cobalt alloys, stainless steel, HSS steels, Tungsten carbides.
One of the main advantages of the Saint-Gobain PTA-PHE cladding system is its capability to produce abrasion resistant overlays by using spherical or angular Tungsten Carbide powders (Cr3C2, TiC… can also be cladded).
Compared to electrodes, TIG, submerged arc, GMAW, the PTA-PHE process results in minimum heat transfer into the part. This leads to numerous benefits.
- While welding, PTA-PHE achieves a faster cooling and quenching of the overlay material, the Heat Affected Zone (HAZ) is practically non-existent with a reduced growth of the metal crystals at the interface.
The dendritic structure is finer, increasing the hardness and improving the wear and corrosion resistance properties.
- With very low dilution rate such as 3 to 5%, the nominal hardness can be reached at thicknesses as low as 0.5 mm. So that thin overlays such as 1.2 mm are possible, with the nominal hardness and the maximum abrasion resistance achieved.
- The heat transfer to the coated part is lowered, reducing the residual stresses by 25% to 100%. The part distortion is minimized with a perfect geometry control of the overlay, close to the final geometry.
This feature is a major advantage when cladding wear plates, thin wall parts and to reduce the machining of overlays harder than 50 HRC.
(Select the Dilution table at above right for an enlarged view.)
- PHE derives from PTA. PHE concentrates more of the arc energy, which allows melting only a few tenth of millimeters of the substrate. The PHE plasma arc is narrow and stable, making it possible to weld thin overlays with a low dilution of the substrate. Less dilution and less damage of the WC particles occur when Ni-WC composites are welded. This results in higher hardness and abrasion wear resistance.
Benefits - Return on invest – ROI
- The Saint-Gobain PTA is a cost effective solution requiring a capital investment of ~70% lower versus a laser cladding equipment.
- The productivity and versatility of the Saint-Gobain PTA equipment allows quick return on investment, no matter if it is integrated on a robot or an X-Y motion system.
- Compared to arc welding, when welding WC composites, the dilution of the tungsten carbide particles is extremely low, so that the abrasion wear resistance is highly improved up to 100%, allowing important savings and return on investment.
- The nominal hardness can be reached at thicknesses as low as 0.5 mm, due to the very low dilution rate of 3 to 5%. This allows to reduce the overlay thickness and the hardfacing time by 30% up to 65% time savings and up to 80% material saving versus GMAW, MIG, TIG or Submerged Arc Welding using cored wires, the PTA technology utilizes materials that are 30% to 50% less expensive for the same ratio power/welding rate.
- PTA has a very high deposit efficiency: up to 95% of the powder is welded onto the part.
- PTA-PHE reduces the excessive distortion of the part which allows to clad wear plates and thin wall parts. PTA-PHE avoids the post-straightening of the parts and reduces the customer claims.
- The high coating thickness accuracy of PTA-PHE allows considerable gains in productivity up to 100%. For specific applications, the post-machining operation can be avoided.
(Select the Cost Comparison table at above right for an enlarged view.)
Typical P.T.A - P.H.E equipment set-up
The Saint-Gobain PTA is recognized as one of the most reliable and accurate systems on the market. Only minimum maintenance is required. The PTA control unit is built from standard components available all over the world (Siemens, Schneider…).