Nickel-based refractory alloy with high chromium content and associated design method

A method for formulating an austenitic alloy based on nickel and having a high chromium content, comprising:

• formulating the alloy to comprise the following elements by mass percentage:
• chromium between 40% and 45%;
• iron between 10% and 14%;
• carbon between 0.4% and 0.6%;
• titanium between 0.05% and 0.2%;
• niobium between 0.5% and 1.5%;
• at least one reactive element, selected from rare earth elements or hafnium, between 0.002% and 0.1%;
• silicon between 0% and 1%;
• manganese between 0% and 0.5%;
• molybdenum and/or copper between 0% and 0.5%;
• an impurity element between 0% and 0.01%;
• and
• nickel to balance the alloy elements;
• and
• selecting the mass percentages of chromium (xCr), iron (xFe), carbon (xC), titanium (xTi), niobium (xNb), silicon (xSi) and manganese (xMn) so that the alloy has a molar fraction (fMX) of secondary carbo-nitrides rich in niobium and/or titanium of more than 0.1%, after subjecting the alloy to an operating temperature between 900° C. and 1150° C.

A method for validating an austenitic alloy based on nickel and having a high chromium content for its use at a given operating temperature between 900° C. and 1150° C., the alloy comprising the following elements by mass percentage:

• chromium between 40% and 45%;
• iron between 10% and 14%;
• carbon between 0.4% and 0.6%;
• titanium between 0.05% and 0.2%;
• niobium between 0.5% and 1.5%;
• at least one reactive element, selected from rare earths or hafnium, between 0.002% and 0.1%;
• silicon between 0% and 1%;
• manganese between 0% and 0.5%;
• molybdenum and/or copper between 0% and 0.5%;
• an impurity element between 0% and 0.01%;
• and
• nickel to balance the alloy elements;
• the method comprising:
• measuring and recording the molar fraction (fMX) of secondary carbo-nitrides rich in niobium and/or titanium in the alloy, after the operating temperature has been applied to the alloy;
• and
• validating the austenitic alloy for its use at the given operating temperature when the molar fraction is greater than 0.1%.