抄録
The authors studied on physical and chemical properties of cast irons with 0·2-4·9%, Cu which have been made by alloying ferro-copper. With mofe than 1% Cu, the graphite of the cast iron becomes refined and the combined carbon increases, dendrites develop, and the peatlite changes into sorbite. The cast iron from cupolas superior to that from eleetric furnaces in its mechanical ploperties, In either case, the inorease of the Cu content acconpanies the rise of hardness. Maxima of tensile, transverse and compressive strengths are attained at 0·5% Cu, but excess of the Cu decreases the strength. Impact value somewhat lowers with the increase of the Gu, while figures pertaining to bending and compression hardly suffer any change. Results. of the dry-method wear-resistance test show no visible change, but the wet-method wear-resistance beeomes abruptly worse with more tban 1% Cu. The cast iron with 0·5% Cu is sufficiently resistant to any of hydrochloric, sulphuric and nitric acid. In every respect of properties, the 0·5% Cu cast iron develops the most excellent properties, and, above all, strength 10% more than the common cast iron and better corrosion resistance. When compared with Nickel-chromium cast irons, the Cu-bearing cast iron reveals lower hardness, higher strength, equal wear resistance and superior corrosion resistance. Copper cast irons of the present grade are suggested to be used as substitute for Nickel-chromium cast irons, indicating a tendency of high grade cast irons developed during the war.
