Advanced rotor forgings for high-temperature steam turbines. Volume 1. Ingot and forging production. Final report

Technical Report · Thu May 01 04:00:00 EDT 1986

OSTI ID:5904251

Swaminathan, V P; Steiner, J E; Mitchell, A

Three advanced steel-melting processes - low-sulfur vacuum silicon deoxidation, electroslag remelting, and vacuum carbon deoxidation (VCD) - were applied to produce three CrMoV (ASTM A470, Class 8) steel forgings for steam turbine application. Ingots weighing about 100 t each were produced using these three processes, and rotors were forged with final weights of about 30 t each. Compared to the conventionally produced forgings, the advanced technology forgings show better tensile ductility and better uniformity along the radial and longitudinal directions. Charpy upper-shelf energy shows about 40% improvement, and no temper embrittlement was found using step-cooled and isothermal-aging treatments. Significant improvement in fracture toughness (K/sub IC/ and J/sub IC/) is realized for these forgings. Low-cycle fatigue life is better at high temperatures because of the absence of nonmetallic inclusions. Creep strength shows slight improvement. However, creep ductility is improved, probably because of low residual elements. The VCD forgings show excellent creep ductility, even with long lives. Both the toughness and creep properties are equal to or better than those of oil-quenched rotors produced by European practices. These improvements are attributed to cleaner steel, better control of ingot solidification, low residual elements (especially very low sulfur content), and the associated reduction of nonmetallic inclusions. These three rotors have been placed in service in three operating power plants in units rated at 520 MW each. Volume 1 of this report covers ingot and forging production, and volume 2 covers mechanical property evaluation.

• Research Organization: Westinghouse Electric Corp., Orlando, FL (USA). Steam Turbine Generator Div.
• OSTI ID: 5904251
• Report Number(s): EPRI-CS-4516-Vol.1; ON: TI86920295
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
200104* -- Fossil-Fueled Power Plants-- Components
36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
ALLOYS
CHARPY TEST
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-MOLYBDENUM STEELS
CREEP
DESTRUCTIVE TESTING
DUCTILITY
FABRICATION
FATIGUE
FORGING
FOSSIL-FUEL POWER PLANTS
FRACTURE PROPERTIES
HEAT TREATMENTS
IMPACT TESTS
INCLUSIONS
IRON ALLOYS
IRON BASE ALLOYS
MACHINERY
MATERIALS TESTING
MATERIALS WORKING
MECHANICAL PROPERTIES
MECHANICAL TESTS
MELTING
PHASE TRANSFORMATIONS
POWER PLANTS
REDUCTION
ROTORS
SOLIDIFICATION
STEAM TURBINES
STEELS
SULFUR CONTENT
TENSILE PROPERTIES
TESTING
THERMAL POWER PLANTS
TURBINES
TURBOMACHINERY