GB583212A - Improvements relating to heat-resisting alloys containing chromium - Google Patents

Abstract

An article or part subjected in use to stress at high temperature, such as a part of an internal-combustion engine or of a steam or gas turbine or other prime mover or of a furnace, is made from an alloy containing 20-95 per cent. of nickel, 5-30 per cent. of chromium, 0-20 per cent. of cobalt, 0-60 per cent. of iron, 0.05-0.5 per cent. of carbon, and one or more of the following: 0.02-1.5 per cent. of titanium, which may be introduced as ferro-titanium, nickel-titanium, or copper-titanium, 0.05-5 per cent. of niobium, 0.05-10 per cent. of molybdenum, 0.05-5 per cent. of tungsten, 0.05-5 per cent. of vanadium, and 0.05-5 per cent. of beryllium, and with or without up to a total of 10 per cent. of other elements such as silicon, manganese, and aluminium, and small amounts of phosphorus, arsenic, antimony, and tantalum, and is heated at at least 1,075 DEG C., e.g., 1,225 DEG C. for long enough for equilibrium at that temperature to be reached, followed by cooling rapidly. The article or part may be reheated before it is put into service to a temperature at or above that to which it will be subjected in service. In order to reduce the initial creep in service, the article or part may first be subjected to stress resulting in permanent deformation, e.g., an elongation of 0.1 per cent. Specifications 495,562 and 504,864 are referred to.