"Technically that's true, but it's probably made of steel, doesn't look like iron, which means it won't melt until you hit 1370 degrees Celsius, so as long as your fire is still orange and not white, you won't warp or melt the sword."

Senku explained, imparting knowledge he actually knew, unlike the magic component.

"You're probably close to 1000 degrees right now, maybe. Give or take."