Wetting of Solid Iron, Nickel and Platinum by Liquid MnO–SiO2 and CaO–Al2O3–SiO2

Wang

et al. 2022

Metals

Industrial tests and thermodynamic calculations were utilized to investigate the source and formation of magnetic particle inspection defects identified on the near-surface of the Cr5 back-up roll forged ingot, which was used in large cold rolling mills. The results showed that the linear aggregating SiO2-MnO-Al2O3 liquid inclusions up to 3 mm led to the flaw detection failure. SiO2-MnO-Al2O3 liquid inclusions were firstly formed in the inductive furnace. Due to its low contact angle, a huge amount of SiO2-MnO-Al2O3 liquid inclusions were inherited into the forged ingot. The formation of SiO2-MnO-Al2O3 liquid inclusions was attributed to the over-oxidation and relatively low aluminum content in the molten steel, as calculated by Factsage 8.1. Controlling the amount of aluminum in molten steel during the smelting process could modify the formation of SiO2-MnO-Al2O3 and CaO-SiO2-Al2O3 liquid oxide into solid Al2O3 type inclusions that were easily removed. Besides, the CaO-SiO2-Al2O3 liquid oxide could be transformed from CaO-Al2O3 type oxide by the significant loss of aluminum content during the VD process or slag entrapment. Certain content of aluminum in the molten steel could improve the flaw detection caused by the aggregating SiO2-MnO-Al2O3 inclusions effectively.

Section: Analysis Of Defective Part On the Ingotmentioning

confidence: 99%

Section: Characteristics Of the Inclusions During The Metallurgical P...mentioning

confidence: 99%

Section: Characteristics Of the Inclusions During The Metallurgical P...mentioning

confidence: 99%

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Formation Mechanism and Improvement of Magnetic Particle Inspection Defects in Cr5 Backup Roller Forged Ingot

Wang

et al. 2022

Metals

“…It was reported that the oxidation of metal can be effectively prevented by adding 5 vol% H 2 in Ar gas [14,15] . In the current study, the volume percent of H 2 in Ar gas was adjusted from 0% to 5% to change oxygen partial pressures.…”

Section: Effect Of Oxygen Partial Pressurementioning

confidence: 99%

Wettability between Fe-Al alloy and sintered MgO

Shen

Zhou

et al. 2017

Ceramics International

In the current study, the wettability between Fe-Al alloy and sintered MgO substrate was investigated. The stable contact angle between the sintered MgO substrate and the liquid iron was approximately 134 o at 1550 o C, hardly influenced by Al concentrations of 18 ppm and 370 ppm in the liquid iron. By changing hydrogen partial pressure from 0 vol% to 1 vol%, the oxygen partial pressure decreased. Meanwhile, the contact angle between the MgO substrate and the liquid iron with 370 ppm Al increased with the decrease of oxygen partial pressure. The oxygen partial pressure and contact angle were scarcely affected by increasing hydrogen partial pressure from 1 vol% to 5 vol%. In all cases with 370 ppm Al in the liquid iron, oxide layers were detected on the surface of iron samples. The oxidation of iron could be effectively prevented by increasing the hydrogen partial pressure. The MgO substrate was reduced to Mg vapor in the reducing atmosphere at a high temperature. Then the Mg vapor was dissolved into the iron even before iron melting. Under thermodynamic equilibrium condition, an oxide layer containing two components, i.e. MgO•Al 2 O 3 phase and CaO-SiO 2-MgO-Al 2 O 3 phase, was generated on the surface of the iron sample. Due to the different wettability between the iron and the two phases, MgO•Al 2 O 3 phase was repelled, while the CaO-SiO 2-MgO-Al 2 O 3 phase adhered to the inside area.

“…Obviously, graphite as a substrate can only be used in a reducing atmosphere and may react with the oxide system [14,21]. The wetting of platinum by the MnO-SiO 2 and CaO-AI 2 O 3 -SiO 2 oxide system was analyzed in [22], where oxide reduction and the dissolution of Mn into the substrate occurred, and the reaction at the phase interface promoted wetting, resulting in dynamic wetting behavior. In the case of the graphite substrate, the absence or minimal wetting by molten oxide mixtures is due to the weak van der Waals forces underlying interfacial bonding [23].…”

Section: Introductionmentioning

confidence: 99%

Wetting of Graphite and Platinum Substrate by Oxide System with Graded B2O3 Content

Novák,

Řeháčková,

Novák

et al. 2023

Crystals

This work focuses on wetting two types of substrates (a platinum substrate and a polished graphite substrate) by molten polycomponent oxide system CaO–MgO–SiO2–Al2O3–B2O3 to test the level of interaction at high temperatures. The tested systems were subjected to high-temperature wetting tests in the temperature range from liquidus temperature to 1550 °C using the sessile drop method. A total of four oxide systems were tested with graded boron oxide contents ranging from 0 to 30 wt%. The experiments were conducted in a CLASIC high-temperature resistance observation furnace and an inert atmosphere of high-purity argon. Droplet silhouettes were obtained with a CANON EOS 550D high-resolution camera during heat treatment, with reactive and non-reactive wetting occurring depending on the substrate type. The dependence of the average wetting angles on temperature and time was evaluated, and it was found that boron oxide decreased the average wetting angles of molten oxide droplets. The analyses were accompanied by the SEM/EDX analysis of the substrate and FTIR analysis of the droplets after high-temperature experiments. The phase composition of the oxide systems was evaluated by XRD analysis.