Cast iron, like steel and wrought iron, is an alloy consisting primarily of iron and carbon but has a carbon content usually in the range of 2- 4%, which appears as flakes of graphite intermixed within the material. Commonly, when cast iron is submerged in a marine environment, the iron component corrodes away, leaving behind the graphite along with iron corrosion products. Iron in this state is often referred to as ‘graphitized’. Fortunately, even though the iron has corroded away, the shapes of cast iron objects recovered from marine sites often remain intact due to the surviving graphite holding the iron corrosion products in situ.
To help illustrate the difference between non-corroded cast iron and graphitized cast iron, last week we x-rayed the damping piston valve cover next to one of its copies cast at the Buffalo State College Foundry.
This oil cup was discovered in 2001 in a mass of concretion withother various tools. These tools are most likely the spilled contents of a tool box and included different sized hammer heads, a small oil can, a lead ingot, and glass from a lantern. The mass was concreted to a large copper alloy pipe.
This object was recovered in 2001 from the Monitor’s wreck site. Since its recovery, there has been much speculation as to the function of the artifact. It has been suggested that this object served as some kind of valve, possibly within a radiator-like system. It is also thought that it may be a component of a monitoring instrument, or even a whistle.