CAST IRON HAVING CORROSION RESISTANCE TO FUMING SULFURIC ACID AND CONCENTRATED SULFURIC ACID SOLUTION

摘要

PROBLEM TO BE SOLVED: To solve problems that a high-silicon cast iron (14 wt.% or more silicon) in which a large amount of Si is added to the iron for use in concentrated sulfuric acid is too hard and fragile to be mechanically worked into a complicated shape, is too greatly shrunk after solidification to be cast, is susceptible to fuming sulfuric acid, absorbs hydrogen to be embrittled, and more liable to cause cracks when melt and solidified into a thick wall structure, because of its fragility.;SOLUTION: The cast iron includes Ni, Cr, Mo, Mn and Cu added to Si and C in a Fe-Si-C composition, in order to give the iron corrosion resistance to sulfuric acid and fuming sulfuric acid. Thereby, the cast iron acquires machinability, precipitates a spheroidized graphite structure therein, promotes conversion of the structure to pearlite, acquires high-temperature strength, secures castability, and inhibits the absorption of hydrogen.;COPYRIGHT: (C)2005,JPO&NCIPI