metallurgist
A specialist in metallurgy; a technical term used in academic and industrial contexts.
He works as a metallurgist at a steel plant.
冶金学 is the field of metallurgy, while 冶金学者 refers to a person who studies or practices it.
Compound of 冶金 (やきん, 'metallurgy') + 学者 (がくしゃ, 'scholar'). The exact derivation of 冶金 is uncertain; it is a Sino-Japanese term conventionally associated with metalworking.