LEARNING OUTCOMES

The purpose of this course is to provide students with basic knowledge of special welding and bonding processes. In the first part of the course will be described in detail the defects found, analyzed the main welding technologies of metallic materials both traditional and innovative. In the second part of the course the concepts of structural bonding will be addressed, introducing the various chemical families of adhesives of industrial interest. Particular attention will be paid to the phases of realization of a glued joint without defects. At the end of the course, students will know the basic concepts on welding and bonding and will be able to recognize the defects that can be found. Thanks to an in-depth analysis of the main welding and bonding techniques, students will have the means to select, among conventional welding or bonding technologies, the one that is most suitable for the material and type of application selected. Visits to laboratories and production plants will make it possible to put into practice the theoretical aspects described in class, immersing students in some of the working realities in which they will be able to operate after graduation.

AIMS AND LEARNING OUTCOMES

The aim of the course is to provide students with basic knowledge of special welding and bonding processes, to describe in detail the diffectologies encountered, and to analyse the main traditional and innovative joining technologies of metallic, polymeric and composite materials. Visits to laboratories and production plants allow the theoretical aspects described in the lessons to be put into practice, immersing students in some of the working realities in which they will be able to work after graduation.

At the end of the course, students will know the basic concepts of welding and bonding and will be able to recognise defects. They will have the tools to establish the geometrical parameters of a joint by selecting the most suitable technique. Thanks to an in-depth analysis of the main welding techniques, students will have the means to select between conventional technologies such as coated electrode, submerged arc, MIG MAG and TIG welding and the more innovative ones such as plasma, electron beam, laser and FSW, the one that is most suitable for the material and type of application selected. With regard to bonded joints, students will be able to select the most suitable adhesive system for bonding polymers and composites in addition to metallic materials.

PREREQUISITES

General materials technology, Mechanical technology, Chemistry

TEACHING METHODS

The teaching consists of lectures, during which the course lecturers will also make use of film clips to provide an understanding of the various aspects of joining techniques and the operating principles of the machinery used to make joints. 

Lectures will be given in the laboratory where it will be possible to see the machinery and products used to make a joint.

Visits are also made to industrial plants and workshops, during which it is possible to witness the various stages of production and quality control of welded and bonded parts.

SYLLABUS/CONTENT

The following topics will be covered during the course:

WELDING

1.      Welding

• Basic concepts of welding;
• Structure of a welded joint, identification of the fused zone and the thermally altered zone;
• Thermal cycles due to welding;
• Stresses and deformations.

2.      Defects found in welding

• Introduction of the main defects found in a welded joint;
• Metallurgical defects;
• Operational defects;
• Applicable normative references, definitions and acceptability criteria.

3.      Preparation of flaps

• Types of preparation;
• Preparation of flaps with thermal cutting.

4.      Welding methodologies

• Introduction and historical background;
• Oxyacetylene welding;
• Principles of electric arc operation;
• Electric arc welding generators;
• Welding with coated electrodes;
• Submerged arc welding;
• Gas shielded MIG/MAG welding;
• TIG welding;
• Resistance welding;
• Innovative types of welding (plasma, electron beam, laser, friction stir welding).

ADHESIVE BONDING

1.      Bonding of materials

• Introduction to bonding: historical background and evolution of bonding;
• Basics of bonding: advantages and disadvantages in the use of adhesives, structure of a bonded joint;
• Cohesive and adhesive bonds and types of joint failure;
• Mechanisms and theories of bonding;
• Surface wettability and methods of analysis.

2.      Adhesives

• Stages in the selection process of an adhesive;
• Chemistry of adhesives;
• Classifications of adhesives;
• Types of adhesives.

3.     Making a bonded joint

• Stages of the manual application process;
• Preparation and surface treatments.

4.     Design of a bonded joint

• Types of stresses acting on a bonded joint;
• Configuration of bonded joints;
• Destructive testing;
• Influence of geometrical parameters on the strength of a bonded joint.

RECOMMENDED READING/BIBLIOGRAPHY

E. Lertora, C. Gambaro, “Tecnologie di giunzione”, Dipartimento di Ingegneria della Produzione, Termoenergetica e Modelli Matematici, Università di Genova, 2010.

Course slides distributed at the beginning of the lessons via the Aulaweb page.