French to English Tech/Engineering Metallurgy / Casting

I'm finding explanations, but no real translations of this term. It's used simply in a table from a report on performance of heat protective asbestos clothing in the steel industry. This function falls somewhere between the "smelter" and the "annealer". Could this be the "caster" or the "reducer" - literally, I am assuming it refers to the person who smooths out the cracks (les criques/fentes) in steel as it is cast?