Forging steel- a moment of science


“The blacksmith, the anvil, the hammer, the whole thing like you’ve seen in the movies.”

All part of a day’s work at Robert Thomas’ workshop to forge iron gates, decorative pieces, and even cookware. The forging process creates a more durable, stronger end product com pared to casting or cutting as the arrangement of molecules in metal, or grains, become compressed. 

“Which gives it strength. If you cut the steel if you were machining it away or grinding it away, you break the grain and create a fracture point in it.” 

Robert Thomas, Owner of Robert Thomas Iron Design

It takes brute force to redirect and compress those grains, but it heat helps as those grains expand move into new positions. Thomas explains, “the easiest way to forge it is to heat it up to a yellow/orange heat. Then it moves very easily, it becomes pliable. Anything clay will do, hot steel will do.”

Watch part one of this series to see the different ways Thomas and his team heats up steel to nearly 2000 degrees at this forge.

Once white hot, blacksmiths go to work hammering the steel. But it’s a race against time as iron cools down to a “red heat,” requiring nearly two times as much force to work with compared to yellow heat as the molecules in the bar become less malleable. Once the iron “cools” below 1500 degrees, it’s back into the fire  to make it workable again. 

Helpful hands from pneumatic hammers can speed up this process, while maintaining the hand-made look. 

Once flattened by hammers, stretched and shaped by pliers, and indented by other tools, the iron work is cleaned and finished by tempering. This increases toughness and reduces brittleness, a by product of forging with high heat, by reintroducing a lower heat.

The result? A product which is 15% stronger by weight compared to other machined metal. Quite necessary for the parts which take a lot of stress- including the pistons in your car’s engine. Forged from steel, but with a basis in science.

Storm Team 2 Meteorologist David Dickson

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