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CNAA / Theses / 2019 / May /

Increasing durability of casting moulds by technological processes and constructive methods


Author: Cosovschi Pavel
Degree:doctor of engineering
Speciality: 05.03.05 - Technology and equipment for pressure working
Year:2019
Scientific adviser: Sergiu Mazuru
doctor habilitat, associate professor (docent), Technical University of Moldova
Institution: Technical University of Moldova

Status

The thesis was presented on the 17 May, 2019
Approved by NCAA on the 27 September, 2019

Abstract

Adobe PDF document – 2.52 Mb / in romanian

Thesis

CZU 621.621.9

Adobe PDF document 14.13 Mb / in romanian
217 pages

Keywords

durability of moulds, diamond smoothing, superficial layer hardening, covering with nanometrical films

Summary

Increasing durability of casting moulds by technological processes and constructive methods. The thesis consists of introduction, five chapters, general conclusions and recommendations, references with 117 titles, 2 annexes, 169 pages (before the references), 103 figures, 15 tables. The obtained results have been published in 7 scientific articles. Key words: durability of moulds, diamond smoothing, superficial layer hardening, covering with nanometrical films. The field of study refers hardening methods by SPD, covering of the active surfaces with protective layers and design of the cooling elements. The purpose of thesis is to deepen theoretically and experimentally the processes that appear with applying of the technology of superficial smoothening and hardening by plastic deformation. Developing a method of numerical simulation with experimental validation. Objections of the thesis: studying the process of hardening and smoothing of the surfaces of machine parts, known and applied in industrial processes, developing a method for making a numerical simulation of the technological processes of treatment by plastic deformation, determination of the material’s properties, validation of the applied properties of the material for modeling the technological process of cold plastic deformation and smoothening with hardening. Experimenting the processes of hardening and smoothening by compressing with a hard tool. Experimental validation of the numerical simulating method proposed and applied in thesis. Scientific novelty and original value of the work consists in elaborating a SPD process for cast iron with lamellar graphites and determinating general procedure to apply PC forecasting process of SPD with appreciating of hardening of the material in superficial layer with improving the surface’s quality. Theoretical significance is in extension of the field of application of the SPD process and elaborating a method of study and developing a PC assisted procedure of SPD, design of the cooling elements and covering of the contact surfaces with protective layers. The important scientific problem solved consists in determination of the general procedure for numerical simulation of the technological processes of treatment by plastic deformation, method of covering of the working surfaces and thermical conditions of work of glass moulds. Application value consists in increasing the resistance of the glass molding material through all three methods elaborated in this thesis. The implementation of the scientific results consists in the application to the glass molds which is confirmed by the implementing documents attached to the thesis.