technique. Points Gravity pouring Low-pressure pour tests [5,6]. Depending on the design, it offers a useful capacity of 1,000 to 10,000 kilograms. Output 20 % - 50 % Increased by a factor of 1.5 -2 The furnace system withmodern IGBT converter technology is designed for steel, Share of rejects Up to 25% depending Reduced by a factor of iron and non-ferrous castings. The pouring (depending on geometry) on geometry 5-10% through laminar and of bronze and copper components is also reproducible mold filling possible with the above-mentioned benefits. Form layout A continuous casting cluster Separated parts Components with a thickness of up to 0.8 mil- (withseveral components → Separation necessary → No separation necessary limeters have been realized by low-pressure per mold) pouring. The average in practice has currently Rework Large feeder and gating Smaller systems Final settled at an average of 1.5 to 2 millimeters, systems dimension sewing for components with a length of up to 1.2 meters. Thanks to the ABP pressure control, Filter Required Not required corresponding casting molds can be entirely filled within a few seconds, without the risk Melting furnace temperature 1700 – 1750 °C approx. 1640 °C of imperfections or porosities if the process → higher energy consumption → lower energy consumption is properly controlled. Low-pressure pouring → short durability of the → longer durability of the thus enables complex and weight-optimized refractory lining refractory material geometries to an extent similar to that of pre- Reproducibility/ repeatability • No controlled flow rate • Controlled low-turbulence cision pouring. In contrast, the significantyl • Temperature fluctuations pressure curv lower manufacturing costs of low-pressure e pouring components and the possibility of during the process • Temperature control possible producing thin-walled components in almost Wall thickness Thin wall thicknesses cannot < 2 mm and < 1 mm local any size. be produced economically The OCN low-pressure pouring furnace is Table 1 . Comparison of process parameters between gravity and low-pressure pouring. designed according to the Teapot principle (Fig. 2).This offers considerable benefits in operation. Besides the high buffering capa- In mechanical and plant engineering, various ring» explains Dr. Marco Rische, CTO at ABP city, the possibility of depositing residual slag machine components up to the drives, espe- Induction. In low pressure pouring, the core in the furnace vessel and slag-free pouring cially for high torque motors, could be cast, process is encapsulated, thus minimizing without the risk of freezing have also proved which in turn could also be used in the auto- problems with sparking, splashing and emis- successful in practical applications. Further- motive industry in the future. The application sions for employees during the pouring more, the crucible inductor allows the OCN of the low-pressure pouring process is not process. In terms of environmental and sus- furnace system to be completely emptied only confined to thin-walled lightweight tainability aspects, thin-walled production quickly, e.g. for an alloy change. Last but not components. The essential advantages, such directly addresses high-strength lightweight least, the furnace has a modular design so as low-turbulence mold filling, reduced construction, which helps to reduce fuel that the individual elements can be replaced gating and feeder systems and adjustable and and energy consumption during operation. easily and quickly at the end of their respective reproducible pouring conditions are equally In terms of production, the possible wall refractory life and the system is highly avai- beneficial for virtually all other areas of appli- thickness reduction in the design process lable. cation in cast steel. IFAM has already built two further reduces energy and material requi- prototype systems and is further developing rements. In comparison to competitor pro- >>> FROM PRACTICE : these for use in cast steel. This gives inte- cesses, this makes it possible to dispense with rested parties the opportunity to test their mixed construction variants or composite INITIAL EXPERIENCE own components in low-pressure pouring materials involving costly recycling processes. without being subject to the boundary condi- As you can see, it is ultimately also about the In contrast to gravity pouring, the low-pres- tions and restrictions of ongoing production. interaction of these operational and environ- sure pouring process is automated to a high It is now possible for the first time not onlyto mental requirements with quality and cost extent. Mold filling is pressure-controlled simulate the technical and economic advan- factors of mass production as well as design and the temperature can be regulated within tages of the process. aspects. a minimum tolerance range. This process therefore resolves the challenge posed by The environmental factor also plays a major >>> THE OCN FURNACE SYSTEM unregulated temperature, because in the high role:Minimizing of circulation and scrap temperature range there is a higher risk of material reduce the energy required per FROM ABP INDUCTION gas porosity, sand inclusions, rough surfaces kilogram of good castings by up to 50 percent. or even mechanical adhesion, while in the Finally, lower quantities of liquid material «The OCN furnace system was developed low temperature range, there is a risk of and lower pouring temperatures mean that on the basis of the established ABP pouring crack formationand inadequate mold filling. less molding material is required, which is furnaces in order to enable the low-pressure In the OCN system, the metal in the furnace is also a major driver of energy consumption pouring process to beusedin caststeel» contained in a closed container with a protec- and costs. «Feedback from our customers explains ABP CTO Dr. Marco Rische. This is tive gas atmosphere. This means that the melt shows that the advantages mentioned subs- the only system for low-pressure pouring of absorbs less hydrogen and other impurities tantially increase the cost-effectiveness steel castings to date that has proven itself in and the oxide formation is minimized. This is of the process in comparison to gravity pou- industrial practice after extensive preliminary the basis for good pouring quality. In addition, 20 • N°19 • SEPTEMBRE 2020