Jin Xin, Tie Xuan, Bi Tie, Mo Tie, Qian Jin, Luo Yin and so on. . .
Mind that the landlord can create some special metal names as his own highlights in the novel.
It's like the protagonist or his master accidentally developed a strange metal or something.
Anyway, fantasy novel, the author is king.
If it's about forging, then metal is secondary. .
Rare materials are king, such as dragon skin and keel. . . .