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1.
John Campbell
Emeritus Professor of Casting Technology Department of Metallurgy and Materials University of Birmingham, UK
FAILURES OF STEELS FROM CASTING DEFECTS
Abstract
The casting of steels in steelworks and in foundries leaves much to be desired. Top pouring is common, and the use of pre-formed refractory tubing is universal. This is technology guaranteed to produce nothing better than mediocre steel, and at worse produces unreliable or even scrap products. The problem centres around the entrainment of air to produce bifilms and bubble trails, both of which are damaging. The causes of failure by simple tensile cracking, fatigue, stress corrosion cracking, hydrogen embrittlement all seem to be the result of a bifilm population in most steels. These failure mechanisms appear to be explained for the first time and will be described. If time allows, the particular failure modes of the costly vacuum induction melted (VIM) and vacuum arc remelted (VAR) steels will be discussed. It is to be noted that these vacuum melting and casting processes cannot be recommended at this time. It will be explained that although electroslag remelted (ESR) steel is currently expected to be significantly more reliable, its reliability should be further improved. It would give the world a fully reliable source of steel for the first time.
Keywords: Steel casting, bifilms, embrittlement, fracture
2.
Rupshree Ozah (1), Muralidhar Manapuram (2)
PhD Scholar (1), Professor (2)
Department of Mechanical Engineering, North Eastern Regional Institute of Science and Technology Nirjuli, India
DEVELOPMENT OF A CONCEPTUAL FRAMEWORK FOR INDUSTRY 4.0 AND ITS SUB-SYSTEMS FOR AUTOMOTIVE PISTON CASTING
Abstract
This paper includes the introduction of different casting manufacturing processes, different shapes and materials used for producing piston. A conceptual framework for piston casting has been developed considering Industry 4.0 technologies for Indian automobiles. Matrix of Industry 4.0 techniques for the piston die-casting, conceptual framework of manufacturing piston by piston crown design, material, shapes, and industry 4.0 techniques considering five materials and five piston head shapes, and four industry 4.0 techniques are highlighted.
Keywords: Industry 4.0, Piston, IoT, Big data, CPS, Die casting
3.
Yajun Yin, Yongjia Zhang, Jianxin Zhou, Xiaoyuan Ji, Xu Shen
State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology,
Wuhan, Kitajska / China
A SHRINKAGE CAVITY MODEL BASED ON MULTI-FORCE FIELDS FOR CAST STEEL GRAVITY CASTINGS
Abstract
Shrinkage cavity defect is a key problem in the production of casting, which affects the quality controlling of castings. Prediction of shrinkage cavity defect with high accuracy contributes to the casting process design and optimization. In this study, a shrinkage cavity model is proposed based on multi-force fields for gravity casting. In this model, a critical pressure criterion that the isolated liquid areas can feed each other is proposed by analyzing the characteristics of connectivity and feeding of the isolated liquid area during the solidification process. The effect of the atmospheric pressure and gravity field on the evolution of the shrinkage cavities are considered to improve the prediction accuracy. The evolution of isolated liquid volumes and shrinkage location is simulated to predict the formation of shrinkage cavity defects. The prediction accuracy of the model is verified by a group of U-type cast steel casting experiment. The location, shape, and the volume of shrinkage cavities obtained by the simulation are in good agreement with the experimental results.
Keywords: Gravity casting; Shrinkage cavity prediction; Pressure distribution; Numerical simulation