Development of Low Alloy Ti-B Steels for High Temperature Service Applications
CORNELL AERONAUTICAL LAB INC BUFFALO NY
Pagination or Media Count:
Conservation of strategic metals may be accomplished in the production of jet aircraft engine parts provided suitable lean alloy substitutes are made available, capable of operating at elevated temperatures. In this respect, the Ti-B type of ferritic steels have been investigated and their creep and rupture properties evaluated and improved for service temperatures in the neighborhood of 1200 degrees F. It was demonstrated, through testing the properties of a 600 pound heat of 3 Cr- 1 Mo-Ti-B sheet steel with a 2.2 TiC ratio, that such a composition not only could be steel mill processed satisfactorily on a semi-commercial basis, but also that 1200 degrees F rupture and creep strength properties equivalent to the Cr-Ni stainless steels, could be obtained for several hundred hours of life. A detailed investigation of this steel provided design type creep data for several conditions of heat treatment and hot rolling procedures. Other tests indicated that high hot strength properties could be retained in light gage sheet material provided surface decarburization was minimized during processing. Ceramic coated creep and rupture test specimens of this alloy displayed a life advantage over uncoated specimens at temperatures above 1200 degrees F because of protection against oxidation. Heliarc welded joints of the 3 Cr- 1 Mo-Ti-B sheet steel had inferior hot rupture strength with respect to the parent metal when no filler rod was used. A reasonable approach to parent metal high temperature strengths was obtained with the use of a 347 stainless steel filler rod with the weld bead left on.
- Ceramics, Refractories and Glass
- Properties of Metals and Alloys
- Fabrication Metallurgy
- Test Facilities, Equipment and Methods