Ferritic stainless steel having high temperature creep resistance
DRIVE
August 20, 2014
The invention provides a method for making a ferritic stainless steel, the steel having a coefficient of thermal expansion within about 25 percent of the coefficient of thermal expansion of stabilized zirconia between 20°C (68°F) and 1000°C (1832°F), and at least one creep property selected from creep rupture strength of at least 1000 psi at 900°C (1652°F), time to 1% creep strain of at least 100 hours at 900°C (1652°F) under load of 1000 psi, and time to 2% creep strain of at least 200 hours at 900°C (1652°F) under load of 1000 psi, the method comprising providing a ferritic stainless steel comprising greater than 25 weight percent chromium, 0.75 to less than 1.5 weight percent molybdenum, up to 0.05 weight percent carbon, and at least one of niobium, titanium, and tantalum, wherein the sum of the weight percentages of niobium, titanium, and tantalum satisfies the equation 0.4 ≤ (%Nb + %Ti + ½(%Ta)) ≤ 1, and solution annealing the steel.
Discussion in the ATmosphere