Effects of Electro-Slag Remelting on Inclusion Formation and Impact Property of Reduced Activation Ferritic/Martensitic Steels

Abstract

The effects of the second refining process, Electro Slag Remelting (ESR), were investigated on Ta rich inclusion formation in the Vacuum Induction Melted (VIM) Reduced Activation Ferritic/Martensitic steel (RAFM), F82H (Fe 8Cr 2W V Ta). The Ta rich oxides such as TaO x and TaO x  Al 2 O 3 are major inclusion in VIMed F82H, and those were correlated with the reduction of the Charpy impact property, as those were found at the crack initiation points. It was revealed that the ESR process was effective on removing those Ta rich oxides. On the other hand, ESR process increased MnS and Al 2 O 3 instead, and these inclusions were found at the crack initiation points. These could explain the little difference on Ductile Brittle Transition Temperature (DBTT) of as VIMed and ESRed F82H.

VHCF response of Gaussian specimens made of high‐strength steels: comparison between unrefined and refined AISI H13

“…In particular, H13 (commercial name Orvar 2 Micronized) is obtained by conventional casting; whereas H13-ESR (commercial name Orvar Supreme) is obtained by conventional casting followed by an ESR refinement process. [20][21][22][23][24] For the investigated H13-ESR, the entire ESR process is performed in a protective atmosphere, in order to limit the hydrogen absorption during the second remelting and enhance furthermore steel cleanliness. 20,21 In particular, large oxides and sulfides inclusions are removed, and micro and macro segregation are eliminated, with the remaining fine inclusions homogeneously distributed within the material after the ESR process.…”

“…20,21 In particular, large oxides and sulfides inclusions are removed, and micro and macro segregation are eliminated, with the remaining fine inclusions homogeneously distributed within the material after the ESR process. [20][21][22][23][24] For the investigated H13-ESR, the entire ESR process is performed in a protective atmosphere, in order to limit the hydrogen absorption during the second remelting and enhance furthermore steel cleanliness. 20 Therefore, the hydrogen content in the two investigated steels can be considered the same.…”

“…The contribution of the hydrogen in the crack growth can be also taken into account to justify the fatigue limit enhancement. [20][21][22][23][24], the total amount of hydrogen before and after the ESR process is the same). [17], hydrogen assistance is modelled by adding a SIF, Δk H , (function Fig.…”

Effect of twice quenching and tempering on the mechanical properties and microstructures of SCRAM steel for fusion application

“…The SCRAM steel was melted by vacuum induction melting and electro-slag remelting (ESR) at argon atmosphere into an ingot of 100 kg, followed by hot-forging and rolling into~24 mm rods. Electro-slag remelting (ESR) at argon atmosphere is helpful for improvement of strength and toughness and decrease of DBTT of the steel compared to electro-slag remelting in the air [16,17]. The as-received state heat treatment consist of quenching and tempering process(named after 1Q&1T)and twice quenching and tempering processes(named after 2Q&2TIand 2Q&2TII), the detailed heat treatment conditions are given in Table 2.…”

Technical issues related to the development of reduced-activation ferritic/martensitic steels as structural materials for a fusion blanket system

“…Additionally, the samples were shown to contain Ta-rich inclusions, which induced dispersion of toughness [7] and fatigue [8]. These inclusions could also induce cracks in the middle plane of the plate in some cases [9]. Thus, it is important to control inclusion formation to minimize the dispersion of mechanical properties and guarantee quality.…”