Foseco has launched the ACTICOTE CG coating range for the improved production of compacted graphite iron (CGI) castings.
These coatings have been especially developed to minimise the degradation of the graphite structure in the rim-zone of CGI castings. Without such preventative measures, there is the risk of the formation of a flake graphite containing skin that can have a thickness of typically up to 1mm, or in some more, which will affect both the mechanical properties and the machinability of the casting.
During the casting process a depletion of magnesium within the solidifying skin of the casting can occur due to reactions of the magnesium with sulphur and oxygen present in the moulding materials and/or in the mould atmosphere. This combined with the undercooling effects at the metal/mould interface can lead to a reduction in compacted graphite formation in favour of flake graphite. ACTICOTE CG coatings act to provide a barrier to core gases and reduce undercooling, reducing the affected reversion layer to a minimum.
Additionally, the coatings have high performance benefits including:
- The refractory filler is highly resistant to the high temperature of the liquid iron and has good insulation properties.
- The coating is formulated with excellent rheological properties making it ideal for the dipping of cores, building the required layer thickness without runs or drips.
- The water-based coating has optimal drying properties without any spalling or the formation of craters or blisters, ensuring the cast surface is free from pin-holes, blemishes or scabs.
See printed edition of the March 2018 issue of Foundry Trade Journal for a more in-depth feature on the technology.
Contact: Tim Birch, international marketing manager - mould & core, email: [email protected]