METALLURGICAL AND METALLOGRAPHIC METHODOLOGIES
Academic year and teacher
If you can't find the course description that you're looking for in the above list,
please see the following instructions >>
- Versione italiana
- Academic year
- 2014/2015
- Teacher
- MATTIA MERLIN
- Credits
- 6
- Curriculum
- INDUSTRIALE
- Didactic period
- Primo Semestre
- SSD
- ING-IND/21
Training objectives
- Aim of the course is to provide knowledge regarding to microstructure of carbon steels and cast irons, according to the production processes and the different bulk and surface heat treatments. The student will learn the most important techniques for the analysis of metallic materials.
Prerequisites
- The student must have the knowledge of the basic topics of the Science of Metals.
Course programme
- Elements of metallurgy: phase diagrams, iron phase diagram, TTT and CCT curves, phase and structural constituents.
Microstructures of steels and of cast irons (white, grey, vermicular and spheroidal cast irons). Etching reagents for steels (ASTM E407, UNI 3137)
Main aspects of iron and steel industry. Production of steels, ingot casting and continuous casting. Hot and cold plastic deformation processes for the production of steel semi-finished products.
Thermodynamical aspects of solidification. Thermal and constitutional undercooling. Major and minor segregations in ingots and in continuous casting bars. Development of micro structural banding in steels (UNI 8449).
Non-metallic inclusions (UNI 3244 e UNI EN 10247): identification of oxides, nitrides, sulfides and methods for reducing the dangers of inclusions.
Analysis of the grain size: methods for the evaluation of the austenitic grain size (UNI EN ISO 643 e ASTM E112).
Practical aspects of heat treatments: quenching, annealing and normalizing.
Superficial heat treatments in brief: practical aspects.
Characterization of metallic materials subjected to thermochemical treatments (carburizing UNI 5381, nitriding UNI 5478, carbonitriding UNI 5479).
Description and identification of the most important defects in steels (due to solidification, heat treatments, machining and mechanical deformation).
Techniques for metallographic inspection (theoretical aspects): visual inspection, optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM). Microanalytical techniques: wavelength dispersive spectroscopy (WDS), energy dispersive spectroscopy (EDS) and electron back-scattered diffraction (EBSD). OES technique in brief. Microstructural analysis with replica technique (UNI 6327, UNI 9993).
Techniques for metallographic analysis (practical aspects): samples’ preparation for metallographic inspection (cutting, mounting, grinding and polishing procedures, chemical etching, observation). Hardness tests (Vickers: UNI EN 6507, Brinell: UNI EN 6506, Rockwell: UNI EN 6508) and Vickers micro-hardness profiles. Shore and Poldi hardness tests.
Part of the course is carried out in the Laboratory of Metallurgy (about 20-24 hours) in order to train the student about the basics of metallurgical procedures and identification of microstructures. These aspects are very important for the working life of the future Mechanical Engineer in all cases of failure analysis and management of a laboratory for the analysis of metallic materials. Didactic methods
- Lectures and laboratory lessons
Learning assessment procedures
- The examination is oral and divided in 2 sections.
The first section is carried out in the laboratory and students have to demonstrate the understanding of the fundamental skills for the metallographic preparation and for the interpretation of the microstructure of metallic materials (in particular, steels and cast irons), in relation to the production processes and to the heat treatments.
The second section is performed in order to assess the understanding of the theoretical subjects tackled in the class. In particular, the ability of critically linking the different subjects covered during the course, rather than the capacity to simpy repeat the specific topics, are evaluated.
Students must show a sufficient knowledge of the topics in both sections of the exam. Reference texts
- 1) G.M. Paolucci, Lezioni di Metallurgia Vol.1 e 2, Ed. Libreria Progetto Padova
2) Lecture handouts
