Speaker
Description
Ingots used for manufacturing pipes, vessels, and shells can be either solid or hollow in cross-section. The technical and economic advantages of hollow forging ingots over solid ones have long been recognized. However, because casting hollow ingots is more complex than casting solid ones, both technologies are still used to produce thick-walled pipes, shells, and high-pressure vessels made of alloy steels for critical applications, particularly in power and petrochemical engineering. A similar situation arises regarding the products required ESR (electroslag remelting) quality. In many cases, forging or rolling critical components is performed from solid ESR ingots, despite the undeniable advantages of ESR hollow ingots for increased production efficiency and improved physical and mechanical properties of the steel used in such components. Initially, ESR hollow ingot technology was developed and applied in Ukraine and several other countries to produce thick-walled pipes and pressure vessels made of high-strength steels using remelting consumable electrodes.
CFHI has recently been exploring the potential of a new ESR technology for large hollow ingots, developed by ELMET-ROLL. The technology involves directly introducing refined liquid metal into a current-supplying mold (CSM), eliminating the need for consumable electrodes. Using two transformers offers additional possibilities for controlling solidification. A mathematical model of hollow ingot solidification was developed, providing a general picture of the temperature distribution in hollow ingots of type 316 steel for various internal mold applications. Key attention is focused on the solidification characteristics of large hollow ingots for power-generating machines and units, primarily made of stainless steel. Comprehensive, step-by-step modeling of the temperature distribution in ingots weighing up to 200 tons and with outside diameters reaching 3000 mm has indicated the need to reduce the cooling rate of the hollow ingot wall near the lower section of the internal mold, a significant factor to consider in their production.
| Speaker Company/University | Lev Medovar |
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