METALLURGY II
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- Versione italiana
- Academic year
- 2015/2016
- Teacher
- MATTIA MERLIN
- Credits
- 6
- Curriculum
- INDUSTRIALE
- Didactic period
- Secondo Semestre
- SSD
- ING-IND/21
Training objectives
- For a proper design of mechanical components and better in-service applications of metallic materials, students must have a deep knowledge of some of the most popular metal alloys and of the factors influencing their microstructure and therefore their mechanical properties. Aim of the course is to give knowledge regarding the characteristics and the properties of some traditional and innovative metal alloys, particularly widespread in the engineering field. The student will acquire the necessary sensitivity to understand the correlation between process, microstructure and properties. On the basis of the acquired knowledge, the student will be able to deal with the choice of the most suitable metal alloys for the realization of mechanical components, according to the specific application and the operating conditions.
Prerequisites
- The student must have the base knowledge of the metal science and of the metallographic structures of carbon steels.
Course programme
- • Materials in mechanical engineering: an introduction. Materials selection charts. (2 hours)
• Introduction to steel production. Classification and designation of steels (UNI EN 10020, UNI EN 10027-1 and UNI EN 10027-2): alphanumeric and numeric designation of steels. Carbon steels and alloy steels (low-alloy and high-alloy steels). (4 hours)
• Quality steels: high strength low alloy steels (HSLA). AHSS, TRIP and TWIP steels. (4 hours)
• Stainless steels. Effect of alloying elements and structural diagrams (Schaeffler diagram). Austenitic stainless steels: sensitization, cold hardening and martensitic transformation (Md). Ferritic stainless steels: sensitization, 475°C embrittlement, precipitation of s phase, extra low interstitial (ELI) stainless steels. Precipitation hardening (PH) steels: martensitic, semi-austenitic and austenitic PH steels. Duplex steels: secondary phase precipitation phenomena, Pitting Resistance Equivalent Number (PREN), heat treatments and superplasticity. (8 hours)
• Maraging steels and High Manganese steels (Hadfield steel). (2 hours)
• Tool steels. Reinforcing mechanisms, effects of alloying elements on mechanical properties, production process and thermal treatments. UNI and AISI designation of tool steels. Cold working, hot working and high speed tool steels. (6 hours)
• Cast irons. Production of cast irons in brief. Solidification processes: influence of alloying elements on microstructure and mechanical properties. Fe-C-Si diagram. Classification and designation of cast irons: white cast iron, grey cast iron, malleable cast iron, ductile cast iron and austempered ductile iron (ADI). Methods of spheroidisation and inoculation of cast irons. Heat treatments, mechanical properties and selection of a cast iron. (8 hours)
• Shape memory alloys (SMAs). Metallurgical aspects of the shape memory effect. Description of OWSME, TWSME and superelasticity. Most important shape memory alloys: NiTi alloys and Cu-based alloys. Introduction to deformable active structures. Applications. (6 hours)
• Welding metallurgy. Metallurgical and microstructural phenomena in weld joints, welding defects. Correlations between i) welding process, ii) morphology of the joint, iii) microstructural features of the joint and iv) mechanical properties. Weldability of carbon steels, alloy steels and stainless steels. (4 hours)
• High temperature alloys. Superalloys. Creep phenomena in metallic materials. (4 hours) Didactic methods
- Frontal lectures on all the course’s topics.
Learning assessment procedures
- The examination consists of oral questions on all the topics covered during the course and 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, rather than the capacity to simply repeat the specific topics, is evaluated. The student must show a sufficient knowledge of the principal characteristics of the different classes of metallic materials for their correct choice and application. The mark is formulated verifying at which level the learning objectives previously described have been acquired.
Reference texts
- • Teacher’s handouts available on the course web page.
• A. Cigada, T. Pastore, Struttura e proprietà dei materiali metallici, McGraw-Hill.
Specific topics can be further learnt in the following texts:
• Cigada, G. Re, Metallurgia Vol.2 - Materiali metallici di interesse industriale, Ed. Clup Milano.
• G.M. Paolucci, Lezioni di Metallurgia Vol.1 e 2, Ed. Libreria Progetto Padova.
• Istituto Italiano della Saldatura, Saldatura per fusione, Vol. 1 e Vol. 2, Hoepli Editore.
• M. Beckert et al., Metallurgia e saldabilità di materiali metallici per fusione, Pitagora Editrice Bologna.
• G. Krauss, Steels: processing, structure and performance, ASM International, 2005
• M. Y. Demeri, Advanced high-strength steels: science, technology and applications, ASM International, 2013.
