Black stain presents as very superficial black spots on a good and smooth casting. This defect indicates that the metal reacted with oxygen forming Chromium (Cr) and Manganese (Mn) oxides during melting, casting and solidification.
Struggling with a specific casting defect or just need general technical support?
Email our technical team at: Technical@ransom-randolph.com.
The causes of this defect are evident in the metal and other portions of the process. To cure these causes, R&R recommends taking the following actions.