Electroslag Refining of CrNiMoWMnV Ultrahigh-Strength Steel

Abstract

Increasing demands for ultrahigh-strength steels in commercial as well as military applications have raised interest in finding alternatives to the high-cost high-alloyed steel and super-alloys currently used, e.g. the use of economic low-alloy compositions processed via low-cost air induction melting and electroslag refining (ESR). In this work the yield of alloying elements and the removal of the impurities nitrogen, sulphur and phosphorus as a result of electroslag refining (ESR) in a newly developed CrNiMoWMnV ultrahigh-strength steel (UHSS) have been studied in relation to their activities in the molten metal pool. Six experimental heats of CrNiMoWMnV UHSS with different chemical compositions were designed, melted in an induction furnace (IF) and refined using ESR. This was followed by hot forging of the ingots at 1100˚C to 950˚C. ESR using a CaF 2 -CaO-Al 2 O 3 slag system led to a high yield in Cr, Ni, Mo, W, Mn and V, while the yield of Si is low. The desulphurization of all six UHSS grades was pronounced with most of the sulphur removed either to the slag or by gas reactions. The degree of dephosphorization was only 5% irrespective of the steel composition. On the other hand, denitrification (removal of nitrogen) was achieved. It ranged from 8% to 63% depending on the steel composition. The yield of the alloying elements and removal of impurities from the steel during ESR depends on the chemical and physical properties of the ESR slag and the activity of the elements in the molten state, taking into account elemental interactions.

The effect of electroslag remelting on the cleanliness of CrNiMoWMnV ultrahigh-strength steels

“…The ESR ingot was subsequently forged and cooled using the forging parameters mentioned above. Our previous publication [23] gives details about the production methods of the investigated UHSSs, the chemical compositions of the charging materials, and the composition of the slag used in the remelting process.…”

Recent Advancements in Material Waste Recycling: Conventional, Direct Conversion, and Additive Manufacturing Techniques

“…Chips can be recycled using methods like electric arc furnace (EAF) [141][142][143][144][145][146], electroslag remelting (ESR) [147][148][149][150][151][152], vacuum arc remelting [153][154][155][156], vacuum induction melting [136,[157][158][159], electron beam melting [160][161][162][163][164], and plasma arc melting [165][166][167][168]. The various conventional processes for remelting chips generated from diverse materials can be further elaborated for understanding.…”

Characterization of the Microstructure and Precipitates Formed During the Thermomechanical Processing of a CrNiMoWMnV Ultrahigh‐Strength Steel

“…The steel with the chemical composition, shown in Table , was melted in an air induction furnace (IF) and refined using electroslag remelting (ESR) in the Steel Technology Department, Central Metallurgical Research and Development Institute (CMRDI), Egypt. The steel ingots were forged in the temperature range 1100–950 °C followed by air cooling at about 0.3 °C s −1 and further details are given in the study by Ali et al…”