Before revision: 300x300px|Thomas converter operational from 1954 to 1964, in Dortmund, Germany The Thomas-Gilchrist process or Thomas process is a historical process for refining pig iron, derived from the Bessemer converter.
After revision: 300x300px|Thomas converter operational from 1954 to 1964, in Dortmund, Germany The Gilchrist–Thomas process or Thomas process is a historical process for refining pig iron, derived from the Bessemer converter.