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J. Jezierski and K. Janerka

Abstract

The concept of Lean Manufacturing (or Lean Production) is widely present in the quality management systems of the best factories. Foundry plants in Poland have continuously been implementing modern management tools; however, the experiences of the authors show that the usage of lean tools is at a lower level in domestic foundries than in similar plants abroad. This was the reason why a survey was prepared and over 300 foundry plants were questioned regarding the application of Lean Manufacturing tools. The questions (20 in total) asked if and what tools are implemented in the plant and what benefits have been achieved, or why lean tools have not been implemented in a particular plant. The answers were thoroughly analysed and the results show that, among others, only 29% of all foundries use lean tools, and the main reason why most of them do not is that these tools are not understood well enough.

Open access

J. Jezierski, K. Janerka and M. Stawarz

Abstract

The method of powder injection into molten metal has been widely known since tens of years and successfully utilized in various metallurgical processes. The most common is a solution with injection lance submerged under the liquid alloy surface, because it is easier apart from some of disadvantages of this approach. In this paper the authors’ complex experiments on the pneumatic injection process with non-submerged lance have been presented. The new approach on jet cone angle importance and its influence on the efficiency of the injection process has been shown. The issue of the effective jet radius that was proposed by former scientists as well as computer modelling and injection experiments recorded with high speed camera have been presented. The final comparison of the typical injection lance and developed by authors new lance with flange was presented, too. The benefits of use of a new one for the treatment of small liquid alloy volume (e.g. inoculation or alloys addition introduction) have been pointed.

Open access

A. Stojczew, K. Janerka, J. Jezierski, J. Szajnar and M. Pawlyta

Abstract

The paper presents the issue of synthetic cast iron production in the electric induction furnace exclusively on the steel scrap base. Silicon carbide and synthetic graphite were used as carburizers. The carburizers were introduced with solid charge or added on the liquid metal surface. The chemical analysis of the produced cast iron, the carburization efficiency and microstructure features were presented in the paper. It was stated that ferrosilicon can be replaced by silicon carbide during the synthetic cast iron melting process. However, due to its chemical composition (30% C and 70% Si) which causes significant silicon content in iron increase, the carbon deficit can be partly compensated by the carburizer introduction. Moreover it was shown that the best carbon and silicon assimilation rate is obtained where the silicon carbide is being introduced together with solid charge. When it is thrown onto liquid alloy surface the efficiency of the process is almost two times less and the melting process lasts dozen minutes long. The microstructure of the cast iron produced with the silicon carbide shows more bulky graphite flakes than inside the microstructure of cast iron produced on the pig iron base.