text: Lancashire process The advantage of puddling was that it used coal, not charcoal as fuel. However, that was of little advantage in Sweden, which lacked coal. Gustaf Ekman observed charcoal fineries at Ulverston, which were quite different from any in Sweden. After his return to Sweden in the 1830s, he experimented and developed a process similar to puddling but used firewood and charcoal, which was widely adopted in the Bergslagen in the following decades.
  Aston process
  In 1925, James Aston of the United States developed a process for manufacturing wrought iron quickly and economically. It involved taking molten steel from a Bessemer converter and pouring it into cooler liquid slag. The temperature of the steel is about 1500 °C and the liquid slag is maintained at approximately 1200 °C. The molten steel contains a large amount of dissolved gases so when the liquid steel hit the cooler surfaces of the liquid slag the gases were liberated. The molten steel then froze to yield a spongy mass having a temperature of about 1370 °C. The spongy mass would then be finished by being shingled and rolled as described under puddling (above). Three to four tons could be converted per batch with the method.