Title: THE INFLUENCES OF CHEMICAL COMPOSITION AND MICRO-STRUCTURE UPON THE GALVANIC CORROSION OF CAST IRON.
Abstract: The corrosion of metals and alloys, especially, iron and Steel have been much studied during past years. However, the investigations on galvanic corrosion or contact corrosion of iron and steel have been carried out comparatively in small circles and very few reports were published. The auther has investigated the influences of chemical composition and micro-structure upon the galvanic corrosion of cast iron specimens, which were immersed in 3% NaCl solution touching with each other. By these contact corrosion tests very small differences of electrolytic solution pressure of cast iron have been recognized clearly, i, e.T.C and Si, by their graphitizing influences, increase solution pressure, while Mn, Cr, Ni, or Cu, decrease it.High-grade cast iron (low carbon, low silicon and high manganese, furthermore, containing Ni, or Cr, ) therefore, will be retarded its corrosion speed by the contact of common cast iron, (higher carbon and silicon). After the completion of graphitic corrosion of common cast iron, however, both corrosion speeds change rapidly, for example, increasing galvanic corrosion of high grade cast iron. The amounts of graphitic corrosion of cast iron specimen will differ by its composition and micro-structure, therefore, by the ingenious selection of these factors, galvanic corrosion of main parts of marine engine will be much more retarded.The investigations of such a practical application will nextly be reported.