Don't you have to be a certain level in smelting to learn that one? That might be why it's not working for you.
The forge is in Hilt. You have to go to Night Shade Pass in the center of the map...and then go into the big fortress guarded by undead and kobolds. Then you have to battle fire elementals that guard the forge. It's really a 3 or 4 man job.
And if you go can you water my hydrangeas next to the forge? The light from elementals make them look extra pretty.
In Hilt Spoiler Below the lich room, In the ghost room on the left side of the room is a secret door To the left of the door almost even with the top of the door is a stone button that opens it. Down that hall wall are two elemental rooms, forge is in the second room.