345-0502/03 – Theory of Welding (TS)

Gurantor departmentDepartment of Mechanical TechnologyCredits6
Subject guarantordoc. Ing. Petr Mohyla, Ph.D.Subject version guarantordoc. Ing. Petr Mohyla, Ph.D.
Study levelundergraduate or graduateRequirementCompulsory
Study languageCzech
Year of introduction2019/2020Year of cancellation
Intended for the facultiesFSIntended for study typesFollow-up Master
Instruction secured by
LoginNameTuitorTeacher giving lectures
MOH37 doc. Ing. Petr Mohyla, Ph.D.
OH120 Ing. Vladislav Ochodek, Ph.D.
Extent of instruction for forms of study
Form of studyWay of compl.Extent
Full-time Credit and Examination 2+2

Subject aims expressed by acquired skills and competences

The aim of the object is to provide students with the complex professional information about the theoretical principles of welded joints formation at fusion and pressure welding, physical principles of the metal welding processes, metallurgical behavior between weld metal and slag or shielding gases, weld metal formation and weld metal crystallization principles, phase transformations in the weld joints, weld joints cracking phenomena, deformation and tension processes in the welds, materials weldability and theoretical principles of materials brazing. Based on the received information the students will be able to independently professionaly solve the task in the technical activities in the field of welding.

Teaching methods

Experimental work in labs


Basic subject for Master's degree in "Mechanical Engineering Technology", focused on welding. Students become acquainted with the principle of the welded joint creation during fusion and solid-state welding and with the importance of thermal cycles and their influence on the structure and properties of welded joints. The course contains basic principles of cracks creation in welded joints and theoretical knowledge about the weldability of different types of materials. Subject included also theoretical background of soldering and brazing. Students will also be informed about welding of heterogeneous materials, welding of cast irons and cast steels, non-ferrous metals and plastics.

Compulsory literature:

BECKERT, M.: Grundlagen der Schweisstechnik, VT Berlin, 1977. EASTERLING, K.: Introduction to the Physical Metallurgy of Welding, BMM, London, 1983.

Recommended literature:

EASTERLING, K.: Introduction to the Physical Metallurgy of Welding, BMM, London, 1983.

Way of continuous check of knowledge in the course of semester

Projects, test.


Other requirements

Active participation in seminars min. 80%.


Subject has no prerequisities.


Subject has no co-requisities.

Subject syllabus:

Lectures: 1. Theory of welded joint creation during fusion welding and solid-state welding. Energy sources used for welding. Weld thermal cycles. Measurement of thermal cycles, calculation of thermal cycles. 2. Theory of heat-affected zone of welded joints. Effect of thermal cycle on HAZ. Precipitation and degradation processes in HAZ. 3. Solidification of the weld metal. Segregation and liquation. External shape factor of weld. Structure and properties of weld metal. 4. Metallurgical processes in weld metal. Theory of slag. Alloying of weld metal. 5. Desulfurization and dephosphorization of the weld metal. Absorption of oxygen in weld metal, desoxidation. Absorption of hydrogen in weld metal. Absorption of nitrogen in weld metal. 6. Cracks in welded joints. Causes of occurrence, susceptibility criteria, cracking tests. Cold cracking, hot cracking, lamellar, annealing , underclad and corrosion cracking. 7. The theory of stress and deformation in welded joints. Calculations. Temporary and residual stresses. Methods of reducing of stress and deformation in welded joints. 8. The theory of soldering. Defects of solder joints. Properties of solder joints. Solderability tests. Solders and fluxes. 9. Welding of heterogeneous joints. Effect of chemical composition and welding methods. Using Schaffler diagram. Problems in welding of heterogeneous joints. 10. Weldability of heat resistant steels 11. Weldability of stainless steels. Weldability of cast irons and cast steels. 12. Weldability of copper and its alloys. Weldability of aluminum and its alloys. 13. Weldability of titanium and its alloys. Weldability of nickel and its alloys. 14. Welding of plastics. Excercises: 1. Introductory exercises. Learning outcomes and competences. Safety training. Repetition of the welding basics. 2. Thermal and deformation cycle of welding, methods of calculation and measurement of temperature cycles. Project No. 1 - Calculation of temperature cycles. 3. Numerical solution of welding temperature fields. 4. Laboratory Exercise - Measurement and Temperature Control of Welding and Heat Treatment. Measurement of temperature cycles in arc welding. 5. Consultation on Project No.1. Analytical and numerical solution of temperature fields. 6. Laboratory exercise: metallographic evaluation of HAZ for selected welding technologies. 7. Entering of project No. 2 - Welding of heterogeneous weld joint. 8. Technologies and techniques of heterogeneous welding joints, welding of non-ferrous metals. Using a virtual welding simulator. 9. Consultation on project No.2. Material Weldability Rating. 10. Laboratory exercise: residual stress measurement, welding deformation, material separation, flame straightening techniques. 11. Welding of plastics, soldering and bonding. 12. Project No. 3 - Determination of weld joints deformations. 13. Excursion to the engineering company. 14. Final Exercise. Test. Evaluation of projects.

Conditions for subject completion

Full-time form (validity from: 2019/2020 Winter semester)
Task nameType of taskMax. number of points
(act. for subtasks)
Min. number of points
Credit and Examination Credit and Examination 100 (100) 51
        Credit Credit 35  18
        Examination Examination 65  33
Mandatory attendence parzicipation: Active attendance at seminars at least 80%.

Show history

Occurrence in study plans

Academic yearProgrammeField of studySpec.ZaměřeníFormStudy language Tut. centreYearWSType of duty
2021/2022 (N0715A270007) Mechanical Engineering Technology P Czech Ostrava 1 Compulsory study plan
2020/2021 (N0715A270007) Mechanical Engineering Technology P Czech Ostrava 1 Compulsory study plan
2019/2020 (N0715A270007) Mechanical Engineering Technology P Czech Ostrava 1 Compulsory study plan

Occurrence in special blocks

Block nameAcademic yearForm of studyStudy language YearWSType of blockBlock owner