Effect of Rolling Temperature on Strength and Low Temperature Toughness of Fe-13%Ni Alloys

Abstract

Thermomechanical treatment was applied to Fe-13%Ni cryogenic alloys for the improvement of the strength and the toughness. The rolling temperature was varied and the relative appreciation was made on the proof stress at 300 K and the impact energy at 77 K of the alloys thermomechanically treated at various temperatures of 900°C, the lower austenite temperature region, 650°C, the α-γ two phase region and 23°C. In the material treated at latter two temperatures, no difference was observed in the combination of the strength and the low temperature toughness. The better combination was obtained by rolling at 900°C and reheating. Anisotropy of the impact energy at 77 K was found to be increased with increasing the strength.
The addition of Ti together with Mo showed marked increase in strengthening and increased the strength of Fe-13%Ni alloys without reducing the low temperature toughness.