It is the rule of the economy — and a challenge for OEMs and MROs (Maintenance and Repair Operations) companies in the mining business: Hard chromium plating costs increase as global demand increases and supply decreases. The industry requires new application techniques, processes, and materials to protect, at reasonable cost, hydraulic cylinders from:
- Side loading
- Shock loading conditions
- High vibration
- High and low operating temperatures
- Sliding abrasion
Metco 1720x family of products are proprietary nickel-based, superalloy hardfacing powders. Overlays of Metco 1720x materials have been optimized to have corrosion resistance similar to that of Inconel 625 and Ultimet overlays, but with superior wear resistance. The Metco 1720x family was designed for laser cladding processes to produce an overlay that combines good wear and corrosion resistance, especially where a crack-free coating is necessary.
It is recommended for applications where the corrosion resistance of an Inconel 625 or Ultimet overlay is sufficient, but better abrasion resistance is required. The key to this design is the precipitation of isolated hard phases in a nickel-based, corrosion resistant matrix. The introduction of the hard phases increases abrasion resistance, but as the hard phases form an isolated morphology, they are not detrimental to the crack-resistance of the overlay. These materials can be clad in multiple layers crack-free, allowing for the overlay to be utilized for rebuild or salvage of undersized parts. The overlay can be ground to a very good finish using silicon carbide wheels.
While Metco 1720x materials provide excellent as-welded hardness and abrasion resistance, some customers have found that taking the additional step to roller-harden the overlays provides even higher hardness and abrasion resistance, which results in further life and performance.
As indicated through ASTM G65-A volume loss testing the abrasion resistance of overlays of Metco 1720x materials are far better than overlays of Inconel 625 or Ultimet, which are commonly used to protect hydraulic rods in marine and non-marine applications where corrosion is a major issue.