text: The cementation process is an obsolete technology for making steel by carburization of iron.  Unlike modern steelmaking, it increased the amount of carbon in the iron.  It was apparently developed before the 17th century. Derwentcote  Steel Furnace, built in 1720, is the earliest surviving example of a cementation furnace. Another example in the UK is the cementation furnace in Doncaster Street, Sheffield.