Course detail
Casting Defects and Repairs
FSI-PVD Acad. year: 2025/2026 Summer semester
The students are familiarized with the classification and terminology of casting defects according to Czech and international standards. The basic types of defects occurring in castings are described, and the physical and chemical causes of their appearance during individual stages of the production cycle are analysed with emphasis on prevention. A number of photographs of real defects and physical samples of castings with defects are presented.
Supervisor
Department
Learning outcomes of the course unit
Prerequisites
Students must have the knowledge of the thermodynamics of metallurgical processes (properties of real solutions, the criterion of the progress and equilibrium of metallurgical processes, equilibria in the melt/gas and melt/refractory systems), the technology of mould and core production (inclusive of the properties of moulding materials), casting and finishing operations in the production of castings, and the metallurgy of foundry alloys.
Planned learning activities and teaching methods
Assesment methods and criteria linked to learning outcomes
Condition of awarding the course-unit credit: participation in exercises. Examination: the knowledge of physical-chemical a nd technological causes of the appearance of basic types of casting defects, remedial measures preventing their appearance, and basic ways of repairing them will be tested.
Attendance in lectures is recommended, attendance in exercises is obligatory.
Attending at the exercises is required, being checked by the leader of practicals. In the case of absence from exercises, the leader assigns a topic for independent written work.
Language of instruction
Czech
Aims
The objective is to make students familiar with the basic types of casting defects and the main reasons for their appearance during individual production stages. They will be led to comprehend the complicated physical-chemical interactions between melts and the surrounding environment (atmosphere, foundry mould) and their effect on the quality of castings.
The course will provide students with the knowledge necessary for determining the kind of casting defect, the reasons for its appearance, and taking remedial measures.
Specification of controlled education, way of implementation and compensation for absences
The study programmes with the given course
Programme N-SLE-P: Foundry Technology, Master's
branch ---: no specialisation, 6 credits, compulsory
Type of course unit
Lecture
26 hours, optionally
Syllabus
1. Introduction to the course, atlases of defects and standards
2. Destructive and non-destructive methods of defect detection
3. Defects occurring during pouring
4. Thermal and mechanical loading of moulds, condensation zone, scabs
5. Melt reoxidation, secondary slag, oxide skins, inclusions
6. Mechanical, thermal and physical-chemical conditions of melt penetration into the mould, surface defects
7. Endogenous pockets of oxygen, nitrogen, and hydrogen; pinholes
8. Gas distribution in foundry mould walls, exogenous pockets
9. Melt crystallization, defects in macrostructure and microstructure, segregation
10. Solidification of castings, contraction cavities
11. Cooling of castings, appearance of cracks
12. Basic ways of repairing of castings
13. Basic ways of repairing of castings
Laboratory exercise
8 hours, compulsory
Syllabus
1. The temperature field in the mould wall (laboratory measurement).
2. Repairs of defects in castings.
3. Repairs of defects in castings.
4. Application of X-ray microanalysis and X-ray diffraction.
Exercise
4 hours, compulsory
Syllabus
1. Definition of the quality of castings, delimitation by means of standards, technical drawings, and technical acceptance terms.
2. Technological aspects of the design of a casting.
Computer-assisted exercise
14 hours, compulsory
Syllabus
1. Modelling the progress of reoxidation processes in the Mathcad program environment.
2. Modelling the blocking of oxygen blowholes appearance in the Mathcad program environment.
3. Modelling the pressure relations accompanying the appearance of nitrogen and hydrogen blowholes in the Mathcad program environment.
4. Modelling the loss of pressure in gating system in the Mathcad program environment
5. Modelling the progress of melt penetration into the casting wall in the Mathcad program environment.
6. Evaluation of the data file of the temperature field in the walls of castings, using the Mathcad program environment.
7. Evaluation of the data file of the temperature field in the mould wall, using the Mathcad program environment.