Furnace rolls are an interesting set of rolls to build. They work in some of the harshest environments. They will typically see temperatures in excess of 500 degrees Fahrenheit for years at a time. Materials used are made to withstand this criteria, so they are also difficult to machine. The above roll body is made from a 300 series stainless steel and has heat shields to protect the 1045 journals.
Typically a stainless steel that could withstand extreme temperatures for extended periods of time.
Some of these rolls have no coatings on them, but some have various coatings like carbide.
These rolls generally operate at high speeds, so they may be dynamically balanced.