Theory and practice of environmental protection in the case of foundries in Europe and Asia

• Experience resulting from the cooperation with the foundries in a few European countries, China and India

• Phenomena and factors affecting the pollution of the natural environment and the implementation of measures aiming at the

environmental protection

Every specialist dealing with foundry processes and their impact on environmental pollution must have encountered in their professional

careers numerous situations in which the theory of environmental protection confronts the stark reality. The discrepancy between theory

and practice can particularly be noticed in foundry engineering in developing countries where the contrasts between different countries and

casting plants are extremely striking. The comparison of working conditions in European and Asian foundries provides a vast scope for

further observations and analyses. Environmental protection seems not only a concern of manufacturers of castings, but also of their

customers whose opinion exerts a significant influence on both the acceptability of working conditions and on the approach to

environmental pollution adopted in metal casting industry.

The article presents a number of examples of various outlooks on environmental issues in foundries manufacturing a wide range of cast

steel and cast iron castings, where different technologies and production processes are applied.

The problem considered in the paper is motivated by production planning in a foundry equipped with the furnace and casting line, which

provides a variety of castings in various grades of cast iron/steel for a large number of customers. The quantity of molten metal does not

exceed the capacity of the furnace, the load is a particular type of metal from which the products are made. The goal is to create the order

of the melted metal loads to prevent delays in delivery of goods to customers. This problem is generally considered as a lot-sizing and

scheduling problem. The paper describes a mathematical programming model that formally defines the optimization problem and its

relaxed version that is based on the conception of rolling-horizon planning

The paper discusses the impact of the geometry of foundry pallet components on the value of temperature gradient on the wall crosssection

during heat treatment. The gradient is one of the most important factors determining the distribution of thermal stresses in these

items. Analysis of quantitative simulation was carried out to detect possible effect of the type of connection between pallet walls and

thickness of these walls (ribs) on the interior temperature distribution during rapid cooling. The analysis was performed for five basic

designs of wall connections used in pallets. Basing on the results obtained, the conclusions were drawn on the best connection between the

ribs in foundry pallets.

Mathematical programming, constraint programming and computational intelligence techniques, presented in the literature in the field of operations research and production management, are generally inadequate for planning real-life production process. These methods are in fact dedicated to solving the standard problems such as shop floor scheduling or lot-sizing, or their simple combinations such as scheduling with batching. Whereas many real-world production planning problems require the simultaneous solution of several problems (in addition to task scheduling and lot-sizing, the problems such as cutting, workforce scheduling, packing and transport issues), including the problems that are difficult to structure. The article presents examples and classification of production planning and scheduling systems in the foundry industry described in the literature, and also outlines the possible development directions of models and algorithms used in such systems.

The problem considered in the paper is motivated by production planning in a foundry equipped with the furnace and casting line, which

provides a variety of castings in various grades of cast iron/steel for a large number of customers. The quantity of molten metal does not

exceed the capacity of the furnace, the load is a particular type of metal from which the products are made in the automatic casting lines.

The goal is to create the order of the melted metal loads to prevent delays in delivery of goods to customers. This problem is generally

considered as a lot-sizing and scheduling problem. The paper describes two computational intelligence algorithms for simultaneous

grouping and scheduling tasks and presents the results achieved by these algorithms for example test problems.

Access to up-to-date information on technology, innovation, source publications, and the materials and services offered in a particular industry is very important for both industrial plants and departmental research centres. It should be noted that obtaining such information using publicly available search engines such as Google, Yahoo!, Bing, Bindu (mainly used in China) is only apparently easy because, due to their versatility, they deliver results with great redundancy. This leads to the need to analyze large data sets by linguistic methods or "manually", which is very tedious and time consuming. In this situation, it was considered reasonable to undertake studies aimed at acquiring relatively simple IT tools, i.e. crawlers, which allow their users to selectively search for information in a particular problem area, which in this particular case is casting. The intention of this work was to collect and analyze the experimental material that would allow describing the characteristics of the above solutions from the point of view of the range of their application, the quality of the results achieved, and possible limitations and preferences taking into account user needs [1, 2].

The paper includes validation studies of the flow module of the NovaFlow&Solid simulation code. Experiments of ductile iron and gray iron casting in a spiral test of castability were carried out. Casting experiments were then carried out in industrial conditions in the Ferrex Foundry in Poznań and the results are the castability spiral length and local cast iron rate during mould cavity pouring. Simulation tests using NovaFlow&Solid Control Volume code were made. The technological castability test was used to determine thermal-physical data through simplified inversion problem. Influence of physical parameters in the database of simulation code on the spiral length obtained as the result of simulation was analyzed. It was found that critical fraction of capillary flow CLFdown has the biggest impact on cast iron castability in the simulation code. The simulations resulted in defining parameters of gray iron GJL 250 and ductile iron GJS-400-15. For the parameters set, the length of castability spiral in simulations was in accordance with casting experiments.

The dimensional accuracy of a final casting of Inconel 738 LC alloy is affected by many aspects. One of them is the choice of method and time of cooling the wax model for precision investment casting. The main objective of this work was to study the initial deformation of the complex shape of a rotor blades casting. Various approaches have been tested for cooling a wax pattern. When wax models are air cooled and without clamping in the jig for cooling, deviations from the ideal shape of the casting are very noticeable (up to 8 mm) and most are in extreme positions of the model. When the blade is cooled in the fixing jig in a water environment, the resulting deviations compared to those of air cooling are significantly larger, sometimes up to 10 mm. This itself does not mean that the final shape of the casting is dimensionally more accurate with the usage of wax models, which have smaller deviations from the ideal position. Another deformation occurs when the shell mould is produced around the wax pattern and further deformations emerge while cooling the blade casting. This paper demonstrates the first steps in describing the complex process of deformations occurring in Inconel alloy blades produced with investment casting technology by comparing results of thermal imagery, simulations in foundry simulation software ProCAST 2010, and measurements from a CNC scanning system using a Carl Zeiss MC 850. Conclusions are so far not groundbreaking, but it seems that deformations of the wax pattern and deformations of the castings do in some cases cancel each other by having opposite directions. Describing the whole process of deformations will help increase the precision of blade castings so that the models at the beginning and the blades in the end are the same.

By the very nature of their work, castings used in furnaces for heat treatment and thermo-chemical treatment are exposed to the effect of many unfavorable factors causing their deformation and cracking, significantly shortening the lifetime. The main source of damage are the micro- and macro-thermal stresses appearing in each cycle. As the cost of furnace instrumentation forms a significant part of the total furnace cost, in designing this type of tooling it is important to develop solutions that delay the damage formation process and thus extend the casting operation time. In this article, two structural modifications introduced to pallets castings to reduce thermal stresses arising at various stages of the cooling process are proposed. The essence of the first modification consists in making technological recesses in the wall connections, while the aim of the second one is to reduce the stiffness of the pallet by placing expanders in the external walls. Using the results of simulation analyses carried out by the finite element method, the impact of both proposed solutions on the level of thermal stresses was evaluated.

The article presents an integrated analytical and measurement system for evaluation of the properties of cast metals and alloys. The presented platform is an extension of the SLAG - PROP application with new modules, which allow to use information on metallurgical processes in an even more effective way, as well as to evaluate the finished product. In addition, the construction of a measuring station for the analysis of thermal processes taking place in a metal bath allows for precise observation of phenomena together with their appropriate interpretation. The article presents not only the cooling curves of certain copper alloys. The analysis also covered mechanical properties related to hardness, finished products depending on the mold in which the products were cast. In the literature one can find information about the mechanical properties of products in the improved state, usually after plastic or thermal treatment, omitting their properties obtained as a result of a naturally made casting. The article also presents the method of placing information in the database using a convenient graphical tool.

In order to predict the distribution of shrinkage porosity in steel ingot efficiently and accurately, a criterion R√L and a method to obtain its

threshold value were proposed. The criterion R√L was derived based on the solidification characteristics of steel ingot and pressure

gradient in the mushy zone, in which the physical properties, the thermal parameters, the structure of the mushy zone and the secondary

dendrite arm spacing were all taken into consideration. The threshold value of the criterion R√L was obtained with combination of

numerical simulation of ingot solidification and total solidification shrinkage rate. Prediction of the shrinkage porosity in a 5.5 ton ingot of

2Cr13 steel with criterion R√L>0.21 m･℃1/2･s

-3/2 agreed well with the results of experimental sectioning. Based on this criterion,

optimization of the ingot was carried out by decreasing the height-to-diameter ratio and increasing the taper, which successfully eliminated

the centreline porosity and further proved the applicability of this criterion.

The paper outlines the methodology of virtual design of a foundry plant as a system. The most important stage in the procedure involves the development of a model defined as a set of data about the system. Model development involves two stages: defining the model’s architecture and specifying the model data in the form of parameters and input-output relationships. The structure is understood as configuration of machines and transport units, representing the sub-systems and system components. As the main purpose of the simulation procedure is to find the characteristics of the system’s behaviour, the merits of the iterative method involving analysis, synthesis and evaluation of results are fully explored.

The article presents a study on the effectiveness of the foundries using Data Envelopment Analysis (DEA) method. The aim of the article

is to analyze the usefulness of DEA method in the study of the relative efficiency of the foundries. DEA is a benchmarking technique

based on linear programming to evaluate the effectiveness of the analyzed objects. The research was conducted in four Polish and two

foreign plants. Evaluated foundries work in similar markets and have similar production technology. We created a DEA model with two

inputs (fixed assets and employment) and one output (operating profit). The model was produced and solved using Microsoft Excel

together with its Solver add-in. Moreover, we wrote a short VBA script to perform automating calculations. The results of our study

include a benchmark and foundries’ ranking, and directions to improve the efficiency of inefficient units. Our research has shown that

DEA can be a very valuable method for evaluating the efficiency of foundries.

The results of research on the effect of the type of cooling agent used during heat treatment and thermal-chemical treatment on the formation of temperature gradient and stress-deformation distribution in cast pallets, which are part of furnace accessories used in this treatment, are disclosed. During operation, pallets are exposed to the effect of the same conditions as the charge they are carrying. Cyclic thermal loads are the main cause of excessive deformations or cracks, which after some time of the cast pallet operation result in its withdrawal due to damage. One of the major causes of this damage are stresses formed under the effect of temperature gradient in the unevenly cooled pallet construction. Studies focused on the analysis of heat flow in a charge-loaded pallet, cooled by various cooling agents characterized by different heat transfer coefficients and temperature. Based on the obtained temperature distribution, the stress distribution and the resulting deformation were examined. The results enabled drawing relevant conclusions about the effect of cooling conditions on stresses formed in the direction of the largest temperature gradient.

This article presents a computer system for the identification of casting defects using the methodology of Case-Based Reasoning. The

system is a decision support tool in the diagnosis of defects in castings and is designed for small and medium-sized plants, where it is not

possible to take advantage of multi-criteria data. Without access to complete process data, the diagnosis of casting defects requires the use

of methods which process the information based on the experience and observations of a technologist responsible for the inspection of

ready castings. The problem, known and studied for a long time, was decided to be solved with a computer system using a CBR (CaseBased

Reasoning) methodology. The CBR methodology not only allows using expert knowledge accumulated in the implementation

phase, but also provides the system with an opportunity to "learn" by collecting new cases solved earlier by this system. The authors

present a solution to the system of inference based on the accumulated cases, in which the main principle of operation is searching for

similarities between the cases observed and cases stored in the knowledge base.

The paper presents a novel Iterated Local Search (ILS) algorithm to solve multi-item multi-family capacitated lot-sizing problem with setup costs independent of the family sequence. The model has a direct application to real production planning in foundry industry, where the goal is to create the batches of manufactured castings and the sequence of the melted metal loads to prevent delays in delivery of goods to clients. We extended existing models by introducing minimal utilization of furnace capacity during preparing melted alloy. We developed simple and fast ILS algorithm with problem-specific operators that are responsible for the local search procedure. The computational experiments on ten instances of the problem showed that the presence of minimum furnace utilization constraint has great impact on economic and technological conditions of castings production. For all test instances the proposed heuristic is able to provide the results that are comparable to state-of-the art commercial solver.