METHOD FOR IMPROVING HIGH TEMPERATURE CHARACTERISTIC AND WELDABILITY OF 9CR-1MO MODIFIED ALLOYED STEEL

摘要

Forgings fabricated from 9 Chromium - 1 Molybdenum, modified alloys are subjected to tempering at a temperature less than the ASTM specified minimum tempering temperature in the range from about 1275 DEG F. to about 1300 DEG F. for a period of time in the range of from about 5 to about 20 hours to cause the forging to have a room temperature yield strength in the range from about 85 to about 100 ksi. Such room temperature yield strengths permit the use of the alloy in the fabrication of high-pressure steam turbine rotors. Forgings fabricated from such alloys possess excellent high-temperature properties and the same are also weldable to facilitate repair of rotors fabricated therefrom and to facilitate the fabrication of the rotor in the first instance by forming the rotor from smaller sections which may be welded together and subsequently tempered at a temperature in the range from about 1275 DEG F. to about 1300 DEG F.