Status of Electroslag Processing for Production of Large Rotor Forgings. Final Report

摘要

Electroslag processed steel is of interest for rotor manufacture and other components of electric power generating units. Electroslag processing has production advantages for the steelmaker and electroslag products have been found to have numerous features of advantage to rotor manufacturers. Electroslag processed steels are cleaner and more homogeneous in structure and chemistry than conventionally processed steels, and excellent combinations of strength, ductility, and toughness can be obtained as a result of those characteristics. There are other attractive features of electroslag processing and products such as high forging yields from ingots and low rejection rates of forgings. Collectively, the good characteristics of electroslag processed steels afford a promise for higher quality rotors and, further along in the development of this technology, larger high-quality rotor forgings than are currently available from conventional techniques. Because of the above potential of electroslag steels, a survey study was initiated, to determine and summarize the worldwide status of the new technology and electroslag products. Electroslag remelting, the basic process, and the modifications of electroslag hot topping, central zone remelting, and electroslag welding were of primary interest. The review of processing status revealed that European and Japanese firms have production capabilities and are supplying electroslag products for rotors and other components. United States firms are developing or planning electroslag production facilities for rotors. Insufficient information on processing, product or operational experience is available to determine clear-cut superiority of processes or products, although survey results should be quite useful as guidance for research and development efforts by organizations interested in exploiting electroslag technology for the production of improved materials for electric generating units. (ERA citation 04:003043)