1) Pig-iron is produced in a furnace by smelting iron ore with a high-carbon fuel: charcoal was used in earlier centuries and then later coke. The molten iron thus produced is run off into rough moulds where it solidifies and forms ‘pigs’.
The first reference to pig-iron in the OED is in 1665 and the term was used in a south Yorkshire document in 1676. The accounts of Colne Bridge Forge contain entries in 1745 for Barnby Piggs
that is pig-iron brought over from Barnby Furnace. In that state it contains impurities and is brittle
unsuitable for making edge tools. It can be converted into cast iron by remelting and blowing air into the molten mass. The Cutlers’ Company had strict rules about the use of pig iron and cast iron but their records show that these were not always observed: 1779 Resolved that all suspicious places shall be searched for Forks made of pig metal. Two cutlers called Parker were later suspected of producing ‘deceitful wares’ and the Company’s searchers found metal forks in their warehouse made of pig iron or cast metal.