Nickel-chromium alloy of improved fatigue strength

A nickel-chromium alloy characterized by enhanced fatigue properties together with good tensile properties and structural stability, said alloy consisting essentially of from 30 to 75% nickel, 12 to 30% chromium, up to 10% molybdenum, up to 8% tungsten, up to 15% cobalt, up to 5% of niobium and/or tantalum, titanium plus aluminum up to 5%, and carbon, nitrogen present and silicon in correlated percentages such that the % carbon+% nitrogen+1/10% silicon is less than about 0.04 to thereby improve low cycle and thermal fatigue strength the balance being from 0 to 50% iron.

As a new article manufacture, a recuperator or bellows made from an alloy consisting essentially of 6 to 12% molybdenum, 19 to 27% chromium, 2 to 5% niobium, up to 8% tungsten, up to 0.6% aluminum, up to 0.6% titanium, carbon present in an amount up to 0.03%, nitrogen up to 0.03% silicon up to 0.35%, the carbon, nitrogen and silicon being correlated such that the sum of % carbon+% nitrogen+1/10% silicon is less than about 0.035%, up to 5% iron and the balance nickel, the alloy being characterized by enhanced fatigue properties as well as strength properties and structural stability.

As a new article manufacture a recuperator or bellows made from an alloy consisting essentially of from 30 to 75% nickel, 12 to 30% chromium, up to 10% molybdenum, up to 8% tungsten, up to 15% cobalt, up to 5% of niobium and/or tantalum, titanium plus aluminum up to 5%, and carbon, nitrogen and silicon in correlated percentages such that the % carbon+% nitrogen+1/10% silicon is less than about 0.04 to thereby improve low cycle and thermal fatigue strength the balance being up to 50% iron.