“White coating”, which frequently occurs in thick-walled castings made of cast iron (GJS, GJL) is a defect many hand-moulding foundries know all too well. It leads to increased reworking and, in the worst case, to scrap. HA helps foundries to solve this problem with a specially developed coating.
The cause of the problem
A molten-metal reaction can occur in thick-walled areas of the casting where metal remains liquid for longer.
These are the areas that experience long reaction times and a high level of moulding material heating.
As a result, extensive pockmark-like roughening and depressions occur on the casting surface. This “orange peel” texture is often marked with a white-bluish layer, which consists of fibrous SiOx.
This results in higher costs due to rework or higher wall thickness allowances and higher testing costs.
The solution
HA offers a special top coat Durosol 9259, which is applied specifically to the affected areas and effectively suppresses the formation of the “white coating” casting defect.
A special component prevents the moulding material from absorbing the sulphur that causes the reaction and thus reduces degradation on the edge of the casting.
Would you like to learn more about HA coatings?
Our coatings team will be happy to assist you at any time.
“White coating”, which frequently occurs in thick-walled castings made of cast iron (GJS, GJL) is a defect many hand-moulding foundries know all too well. It leads to increased reworking and, in the worst case, to scrap. HA helps foundries to solve this problem with a specially developed coating.
The cause of the problem
A molten-metal reaction can occur in thick-walled areas of the casting where metal remains liquid for longer.
These are the areas that experience long reaction times and a high level of moulding material heating.
As a result, extensive pockmark-like roughening and depressions occur on the casting surface. This “orange peel” texture is often marked with a white-bluish layer, which consists of fibrous SiOx.
This results in higher costs due to rework or higher wall thickness allowances and higher testing costs.
The solution
HA offers a special top coat Durosol 9259, which is applied specifically to the affected areas and effectively suppresses the formation of the “white coating” casting defect.
A special component prevents the moulding material from absorbing the sulphur that causes the reaction and thus reduces degradation on the edge of the casting.
Would you like to learn more about HA coatings?
Our coatings team will be happy to assist you at any time.