GB371334A - Process for improving the mechanical properties of ferro-nickelchromium alloys - Google Patents

Abstract

371,334. Alloys ; annealing. SOC. ANON. DE COMMENTRY, FOURCHAMBAULT ET DECAZEVILLE, 84, Rue de Lille, Paris. Oct. 13, 1930, No. 30605. Convention date, Oct. 11, 1929. [Classes 72 and 82 (i).] In a process for hardening ferro-nickelchromium alloys in which the proportions of nickel and chromium are comprised within the hatched area of the accompanying diagram, one or more elements more soluble when hot than cold in the ferro-nickel is or are added to the alloy, e.g. carbon less than 1 per cent, aluminium 1-7 per cent, silicon 0-5 per cent, copper 0-20 per cent, and beryllium 0-5 per cent, and the alloy is rapidly cooled from 800-1150‹ C. and then hardened by annealing for a period of 2-200 hours at 400-900‹ C. The nickel may be partially replaced by cobalt and aluminium mav be used with silicon or aluminium and carbon with silicon, or copper in the presence of aluminium or aluminium and silicon or silicon as the hardening agent, the silicon being replaceable by beryllium. The alloy may be forged, rolled or cast at temperatures higher than 800‹ C. and then hardened by annealing at 400-800‹ C. In an example, an alloy treated contains 1-7 per cent of aluminium, 7-80 per cent of nickel, 5-40 per cent of chromium, 0À3-4 per cent of manganese, 0-10 per cent of tungsten, 0-10 per cent of molybdenum, 0-5 per cent of titanium, 0-2 per cent of vanadium, 0-3 per cent of silicon, the rest being iron.