GB620676A - Improvements relating to nickel, cobalt, chromium base alloys - Google Patents

Abstract

A hardenable alloy consists of 10 to 72 per cent nickel, 10 to 39.5 per cent cobalt, 15 to 40 per cent chromium and 2.7 to 5.7 per cent aluminium, the aluminium being present with 1.55 to 3.5 per cent titanium and without silicon or with up to 1.5 per cent silicon, or both together up to 4 per cent, molybdenum, vanadium, tantalium or tungsten either singly or two or more together up to 6 per cent, up to 0.4 per cent carbon, and up to 0.5 per cent iron, wherein the sum of the nickel and cobalt contents together is above 37 per cent, and the ratio of such sum to the sum of the contents of aluminium plus silicon plus twice the squart root of the titanium is between 5 : 1 and 10.7 : 1. The alloy can be forged or hot-worked between 1100 DEG and 1225 DEG C. It can be solution-treated at between 950 DEG and 1300 DEG C. for a period of up to 24 hours and then rapidly quenched or cooled in air. The alloy may then be precipitation-hardened by reheating at a temperature between 650 DEG and 850 DEG C. for a period of up to 24 hours and finally quenching or cooling in air, or in the furnace. Specifications 572,779, 572,861 and 583,845 are referred to.