As its name suggests, however, cast iron is meant solely to be cast; it cannot be forged. ... On the other hand, steel can be either cast or forged into the desired shape. It can also be welded and is generally stronger than cast iron, making it a suitable choice for high-pressure, high-temperature use.

Why is cast iron not weldable?

It is possible to weld cast iron, although it can be problematic due to the high carbon content. ... The welding process causes this carbon to migrate into the weld metal and/or the heat affected zone, leading to elevated brittleness/hardness. This, in turn, can lead to post weld cracking.

Is cast iron good for knife making?

Steel with around 0.3% carbon or less is structural or mild steel and will not harden to form a proper hamon or a durable cutting edge (though it is a useful practice material for learning to forge). Wrought iron has almost no carbon and will not harden. Cast iron is brittle and cannot be forged without crumbling.