Complex sentence: The puddling process began to be displaced with the introduction of the Bessemer process, which produced steel, which could then be converted into wrought iron using the Aston process for a fraction of the cost and time.
Split into simpler sentences: The puddling process began to be displaced with the introduction of the Bessemer process, which produced steel. This could be converted into wrought iron using the Aston process for a fraction of the cost and time.