Roderick Ian Lawrence Guthrie

• B.Sc. Eng. (Hons), Ph.D.(Process Metallurgy)
• Professor at McGill University

Gas bubbling can be an effective means to float out alumina inclusions from liquid steel in a ladle. However, large spherical cap bubbles are formed when using porous plugs, as the liquid steel is nonwetting to the porous refractory. These bubbles rise rapidly through the liquid steel, forming a fast‐moving bubble plume, restricting contact times....

The horizontal single belt casting (HSBC) process has proven itself to be a viable casting process for strip casting of a wide range of metallic alloys, e.g., commercial aluminum alloys, advanced high strength steels, copper alloys, as well as some bulk metallic glasses (BMGs). The HSBC process offers advantages vs conventional strip casting proces...

Non-metallic inclusions less than 50μm are presently impossible to be removed during typical liquid metal processing operations, even though their presence can have a negative impact on the properties of final products. The major purposes of injecting gas and generating microbubbles within a liquid metal bath include superior intermixing of reactan...

Argon bottom stirring is commonly practiced in secondary steelmaking processes due to its positive effects on achieving uniform temperatures and chemical compositions throughout a steel melt. It can also be used to facilitate slag metal refining reactions. The inter-mixing phenomena associated with argon gas injection through porous plugs set in th...

The Ladle Shroud has become an important part of secondary steelmaking, with its role in reducing liquid steel contamination and process improvements. Due to the inherent negative pressure at the lower nozzle–Ladle Shroud joint, it is well known that Ladle Shrouds, protecting steel flows between a Ladle and a tundish below, can suffer from inadvert...

The Horizontal Single Belt Casting (HSBC)Horizontal Single Belt Casting (HSBC) process involves castingCasting a thin “river” of molten metal directly onto a fast-moving, continuously cooled, endless belt. By castingCasting at higher cooling rates than is common, uniform solidificationSolidification rates across unconstrained “thin sheets” of meltM...

The empirical relations that govern multiphase interactions between microbubbles and inclusions indicate a strong dependence between bubble size and overall inclusion capture efficacy. Established probability models highlight the need for bubbles less than 1 mm in diameter for optimal inclusion capture. To achieve bubbles in this size regime, tange...

This historical review of casting methods used to produce sheets of steel for automobiles, household products, rocket bodies, etc., all point toward the development of one-step commercial processes, which are capable of casting liquid steel directly into a final sheet product. Progress towards this goal is confirmed by successful advances being mad...

Horizontal Single Belt Casting (HSBC) is one of the emerging Near-Net-Shape Casting (NNSC) Processes for producing thin strips directly from liquid metal. It has been shown to have several advantages compared to the traditional Continuous Casting (CC), and Direct Chill (DC) casting routes. Nevertheless, some process conditions need to be thoroughly...

Gas was injected into the upper part of a water model ladle shroud, producing micro-bubbles by the shearing action of the high-speed entry flow of water, combined with subsequent bubble breaking actions of turbulence. An impact pad was used in favor of a standard turbulence inhibitor, to maintain the integrity of the micro-bubbles, and assure their...

In this research, AA6111 aluminum alloy strips, 250 mm wide and ~6 mm thick, were produced via the horizontal single belt casting process. The strip microstructure was analyzed using optical and scanning electron microscopy, and the measured average grain size was 90 μm. This is significantly smaller than the average grain size of the products prod...

A novel ladle shroud was employed to produce small bubbles to remove inclusions smaller than 50 μm meanwhile inhibiting the formation of slag eye. Both water modeling and industrial tests were carried out to confirm the generation of small bubbles with the ladle shroud. The numerical model was developed to investigate slag-metal interfacial behavio...

This research presents numerical modeling and experimental results on thin strips of Fe‐21%Mn‐2.5%Al‐2.8%Si‐0.08 %C wt.%. steel, obtained using the HSBC process. It was found through CFD studies, that the free stream of the molten metal, exiting from a nozzle slot, can become highly unstable and non‐uniform, after interacting with a 30° inclined re...

In the metallurgical industry, Liquid Metal Cleanliness Analyser (LiMCA) commercial equipment cannot distinguish between hard particles (e.g., oxides, borides) and deformable particles (e.g., bubbles, molten salts). Therefore, hard particle concentrations can sometimes be grossly overestimated, which reduces the measurement accuracy. However, the m...

In this research study, numerical modelling and experimental casting of AA6111 strips, 250 mm wide, 6 mm thick, was conducted. The velocity of the molten AA6111 alloy at the nozzle slot outlet was raised to 2 m/s, whilst the belt speed was kept at 0.3 m/s. The numerical model demonstrates considerable turbulence/fluctuations in the flow of the molt...

This paper presents optimum operating parameters for the production of thin strips of 40 mm in width and ∼4 mm in thickness of Fe–17%Mn–4%Al–3%Si–0.45%C wt-% TWIP (TWinning Induced Plasticity) steel using the present version of the Horizontal Single Belt Casting (HSBC) process. A two-dimensional model was developed to examine the flow of molten met...

Micro-bubbles were generated using gas injection through tiny orifices located at the upper part of the ladle shroud, for deep cleaning the liquid steel. An impact pad was employed to improve the dispersion of micro-bubbles in the liquid bath, reduce the collision between bubbles, as well as to achieve the conventional functions of a turbulent inhi...

The control of fluid flows within the mold region of continuous casters is a key factor in improving the quality of cast products. The performance of two different flow modifiers in the curved mold region of a typical square billet caster are compared. The flow modifiers investigated in this work are a 5‐ported Submerged Entry Nozzle (SEN) and a Br...

Horizontal Single Belt Casting is by far the simplest of all near net shape casting machines and is ideally suited to replace current slab caster operations, given its matching productivity, ‘green’ characteristics, and lower capital and operating costs. In the present paper, numerical simulations based on the Volume of Fluid method were utilized t...

Both physical experiments and mathematical simulations were employed to investigate the transport phenomena involved during Horizontal Single Belt Casting (HSBC) of AA6111 aluminum alloy, using an inclined feeding system. Flow instabilities in the metal delivery system were first analyzed, and it was found that the first impingement gives rise to i...

steel slag material demonstrated rapid hardening and a considerable gain in compressive strength upon reacting with carbon dioxide. Two-hour carbonated paste compacts achieved an average compressive strength of 80 MPa, warranting the slag's consideration as a cement-like binder for building applications. The microstructure of this CO2-activated bin...

An electromagnetic field simulation along with a fluid flow analysis model were developed, to study the effect of the submerged entry nozzle’s (SEN) angle of rotation, together with a rotational electromagnetic field, on the turbulent liquid steel flow within a curved, square mould of a billet continuous caster. The Realisable-k-ϵ turbulence model...

Having knowledge of fluid flows within the mold region of a billet continuous caster is of paramount importance to reduce a product’s internal and external defects. In this regard, a three-dimensional numerical model was developed to simulate the influence of the orientation of a five-port submerged entry nozzle (SEN) on the flow field of liquid st...

Horizontal single belt casting (HSBC) has great potential to replace current conventional continuous casting (CCC) processes for sheet metal production, by directly casting 3 to 1 mm sheet for the automobile industry. In the present paper, two-dimensional mathematical models were developed to study transport phenomena, for the case of an inclined w...

The effect of interfacial wettability on the size of gas bubbles releasing from orifices submerged in high velocity cross flow coupled with strong turbulence, was investigated in a full-scale water model of a commercial ladle/tundish/mold system, located at the McGill Metals Processing Centre. The present work attempted to simulate bubble formation...

This work demonstrated the possibility of producing artificial carbonate aggregates from steel slag optimally activated by carbon dioxide for the purposes of waste recycling and carbon utilization in concrete. The value-added application is unique and oriented towards green concrete development. Processing of the slag involved successive carbonatio...

Gases are now widely used for stirring purposes in liquid metals , given the inventions of the porous plug, as well as other submerged gas injection methods, such as through nozzles, or tuyeres. Nonetheless, we know that any small bubbles forming at the exit pores of porous plugs, will normally rapidly coalesce into much larger bubbles. So, the que...

Gas bubbling through a ladle shroud can be an effective approach for the removal of inclusions. However, an exposed eye of steel often appears in the slag cover surrounding the ladle shroud, owing to re-surfacing bubbles leading to the formation of an exposed eye of steel, termed a “slag eye,” resulting in heat losses and re-oxidation of the liquid...

Due to the increasingly stringent cleanliness requirements for final products, the injection of microbubbles into a full scale water model of a Ladle-Tundish-Mould system was identified as a way of modelling the removal of very small inclusions (< 50μm dia) from liquid steel passing through the steelmaking tundish. However, how to generate micro bu...

The conventional continuous casting (CCC) of steel, starting in the 1950s, has now become the dominant casting process, worldwide. It presently accounts for about 1.5 billion tonnes of steel cast per year. Nonetheless, given the inexorable forces favouring near net shape casting (NNSC) of semi-finished products, for reasons of economy of scale, pro...

Water modeling, using microbubble swarms, was performed in a full-scale, four-strand, delta-shaped tundish, located at the McGill Metals Processing Centre (MMPC). The objective of the study was to investigate the effectiveness of microbubbles in removing inclusions smaller than 50 μm, applying the principles and conditions previously researched usi...

The horizontal single belt casting (HSBC) process has been proposed as an efficient, economical, and environmentally friendly alternative approach to the production of ferrous alloys. Low carbon steel strips were cast using the HSBC simulator apparatus to study the characteristics and properties of the as-cast steel strips. Three-dimensional comput...

Water model experiments were performed in a full-scale, delta-shaped water model tundish, in order to study the removal of inclusions by micro-bubbles. Micro-bubbles were generated using a specially designed ladle shroud with twelve laser-drilled orifices. Gas flow rates, injection positions and multi-port injection were all taken into consideratio...

An experimental study was undertaken to determine the effects of chlorine gas volume fraction (0–25%) in the fluxing gas, fluxing gas flowrate (7.79–27–07 cc/sec @NTP) on the rate of removal of sodium from aluminum and aluminum-1 wt% magnesium alloys. For this purpose, fluxing gas was introduced into a 7.5 kg melt by an upward facing nozzle and bub...

Although the importance of settling in controlling the concentration of non-metallic inclusions in aluminum melts has long been recognized, its quantitative study has so far been limited, due largely to the combined difficulties in estimating the parameters of the separation process and in obtaining quantitative measurements. This paper will presen...

Horizontal Single Belt Casting of strips is a green strip casting technology, potentially capable of replacing current DC and slab caster operations. As-cast strip bottom surface quality is a key factor for the near-net shape casting operations. The meniscus behavior at the triple point of gas, substrate, and liquid metal, where the melt first touc...

Scandium containing Al-Mg alloys exhibit significant potential for use in aerospace applications, such as air frames and stiffened panels. Zirconium additions further improve the room temperature (RT) workability, elevated temperature resistance and mechanical properties of these alloys. In this study, the capability of the Horizontal Single Belt S...

The feasibility of developing a high strength KOBM (Klockner Oxygen Blown Maxhutte) steel slag binder activated by carbonation as an alternative cementing material was investigated. After two-hour carbonation reaction, steel slag compacts displayed a 2 h compressive strength of 80 MPa with a CO2 uptake of 13%. Early strength gain was attributed to...

Al-Mg-Sc-Zr alloys have shown exceptional potential as structural materials for transportation applications. These alloys have proved to be good candidates to be processed as thin strips via the horizontal single belt casting (HSBC) process. The HSBC process is a near-net-shape casting technology, which involves casting molten metal directly into t...

Horizontal single belt casting (HSBC) is a near net shape casting process in which molten metal is directly cast into thin strips, at high cooling rates (order of several 100 °C/s), with the potential for high volume, friction free, continuous production of metal strips. This casting process was used in the present work to produce strips of Al-Mg a...

A preliminary computational fluid flow model has been developed to simulate the magnetic braking of liquid steel on a water-cooled, rapidly moving, horizontal belt. The liquid steel issuing from the proposed vertical slot-nozzle should ideally move isokinetically with the belt during freezing. In this study, ANSYS Fluent 14.5 software was used to m...

Section 4.7 makes use of the preceding sections to propose a new casting system, called HSBC, or Horizontal Single Belt Casting, to produce steel sheet products. Following a review of Conventional Continuous Casting and Thin Slab Casting processes, the process overview goes to Near-Net –Shape-Casting processes. The two NNSC processes analyzed are T...

This chapter briefly reviews the key concepts and equations of heat and mass transfer, and of fluid flows, some of which have already been presented in earlier chapters. It also introduces Maxwell's equations for handling the electromagnetic processing of liquid metals. It then goes on to describe the basic underpinnings of computational fluid mech...

Section 4.4 reviews recent research work probing the fundamental ways in which heat is transferred to the mould when contacted by a liquid metal. It is demonstrated that perfect thermal contact is not normally established, since the liquid metal sits on a few points of contact with the substrate, and the vast majority of the substrate receives heat...

Section 4.3 provides an updated literature review and discussion of the many metallurgical processes that have been modelled using Computational Fluid Dynamics (CFD). Following a brief introduction to CFD techniques, their application to flows in Iron Blast Furnaces and to the design of these impressive reactors, and to others, such as COREX, FINEX...

Section 4.6 considers single, two phase, and multi-phase flow systems, and methods to analyse them, mathematically, using CFD techniques. Most metallurgical processes are essentially multiphase flows involving liquid metals, molten slags, and gases. Additionally, one can have particle and gas laden flows, so it is important to choose the right mode...

Section 4.5 reviews recent computational and physical modelling of solidification in conventional continuous casting (CCC) and thin slab casting (TSC). The section presents one of the key contributions to the successful development of continuous casting in the early 1960's, the development of oscillating molds. Typically, the molds of slab, billet,...

Section 8.8 summarises the value of kinetic models of processes, which are able to predict the path of given reaction, or process, as it moves from the initial state to its end point. It must necessarily incorporate thermodynamic relations to describe species concentrations at reacting interfaces, but, unlike thermodynamics, kinetic models contains...

The Al-Mg-Sc-Zr alloys have shown exceptional potential as structural materials for transportation applications. These alloys have proved to be good candidates to be processed as thin strips via the Horizontal Single Belt Casting (HSBC) process. The HSBC process is a near-net-shape casting technology, which involves casting molten metal directly in...

Horizontal Single Belt Casting (HSBC) is a near-net-shape casting process in which molten metal is directly cast into thin strips, at high cooling rates (order of several 100°C/s), with the potential for high volume, friction-free, continuous production of metal strips. This casting process was used in the present work to produce strips of Al-Mg al...

The horizontal single belt casting of steels and non-ferrous alloy systems is by far the simplest of all near net shape casting machines (NNSC), but paradoxically, the least researched, and tested. With the imminent start-up of the world's first horizontal single belt casting (HSBC) caster manufactured by SMS Siemag for operation at Salzgitter's st...

Horizontal Single Belt Casting (HSBC) is a near net shape strip casting technology that will probably gain significant prominence in the coming years. Fluid mechanics and associated heat and mass transfer are important aspects of any continuous casting process, and the HSBC process is no exception. In this study, mathematical models have been devel...

The HSBC is an ideal process for the production of BMG strips. The purpose of the present work was to investigate the casting of Ca-based, bulk amorphous strips. The possibility of casting three Ca-based alloys (60Ca-20Mg-20Al, 60Ca-15Mg-10Al-15Zn and 55Ca-15Mg-10Al-15Zn-5Cu (at.%).) was investigated, using the HSBC simulator. Numerical simulation...