Two science papers from Quaker Chemical Corp. are worth reading for what they say about key developments in metalworking technology.
Modern Machine Shop, Mark Albert,
“Lubrication & Machining of Compacted Graphite Iron” starts by asserting that a deeper understanding of the machining properties of compacted graphite iron (CGI), along with an understanding of the metalworking fluid properties required to reduce wear and extend tool life in CGI machining would benefit the industry and promote wider use of CGI. I found this paper to be a worthwhile step in that direction.
As the paper clearly explains, the properties of CGI that yield stronger, lighter components than those made of gray cast iron are the same properties that make the material difficult to machine and cause rapid tool wear. One of the properties of CGI is the absence of sulfur, the alloying substance in gray cast iron that helps make it so machinable while prolonging tool life. So how about adding sulfur to the metalworking fluid? Does this additive compensate for the sulfur missing in CGI?
The findings presented in the paper indicate that it does. The important benefits that follow are well explained. With or without this “happy ending,” the story of why gray cast iron and CGI are destined for very different fates makes this a worthwhile read.