Pig Iron

Pig Iron is a material added by Tinkers' Construct. It is primarily used to create tool parts by being poured into a Casting Table with a cast already on it. In Minecraft versions 1.8.8 and onwards, parts formed with this material allow the player to eat the tool when holding the right-mouse button to restore hunger while sacrificing some of the tool's durability.

Recipe
It is formed in the Smeltery by alloying molten iron, blood and clay.