ThomasPowers Posted May 31, 2012 Share Posted May 31, 2012 Sorry didn't get a chance to dive into my library last night---my youngest Daughter is getting married today and things were at sixes and sevens round my place. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted June 1, 2012 Share Posted June 1, 2012 OK every went to the city to celebrate and I was stuck home---have to work today so: "Metal Technology in Medieval India" says that they would pack castings in "pulverized iron ore and heating them to bright redness for many days"...."Lengthy heat-treatment in this temperature range slowly removed the carbon present as iron carbide in the metal as cast. This decarburization was partial to complete, according to the thickness of the casting and the temperature and time of heating. The metal thus produced was almost free from carbon and for the first time provided ferrous castings possessing some toughness and ductility." "The packing performed three functions: First, it supplied the oxygen for oxidizing the carbon, second, it supported the castings that otherwise would have softened and lost shape under the applied heat, third, it acted as a 'buffer', shielding the castings from direct contact with the furnace atmosphere---a contact which in the long period of heating would have caused undue oxidation of the iron as well as the carbon, creating a heavy scale on the castings and perhaps even destroying thin sections." Note that what you get from this process is not wrought iron as it does not have the definitive ferrous silicate spicules in it. Other indirect methods required the addition of silicates often from the bed of the furnace or as in the byers process adding slag to the iron and mixing. (This book has a description of how they refined zinc way before the Europeans figured it out that is pretty wild and is not nearly so jingoistic as most of the "China did it first" books I have read.) Quote Link to comment Share on other sites More sharing options...
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