Performance of MONEL Alloy 400 in Feedwater Heaters

With access to data on more than thirty years service experience with MONEL alloy 400 tubing in high-pressure feedwater heaters, the Huntington Alloy Products Division conducted an extensive laboratory investigation on mechanisms and corrodents contributing to stress-corrosion cracking in this application. A mechanism by which copper-nickel and nickel-copper alloys fail through stress-corrosion cracking is proposed. Changes in manufacturing procedures make it possible to achieve material highly resistant to failure by this mechanism.