618-3023/04 – Molding mixtures (FS)

Gurantor departmentDepartment of Metallurgy and FoundryCredits6
Subject guarantorIng. Jaroslav Beňo, Ph.D.Subject version guarantorIng. Jaroslav Beňo, Ph.D.
Study levelundergraduate or graduateRequirementCompulsory
Study languageEnglish
Year of introduction2019/2020Year of cancellation
Intended for the facultiesFMTIntended for study typesFollow-up Master
Instruction secured by
LoginNameTuitorTeacher giving lectures
BEN001 Ing. Jaroslav Beňo, Ph.D.
Extent of instruction for forms of study
Form of studyWay of compl.Extent
Full-time Credit and Examination 3+3
Part-time Credit and Examination 16+0

Subject aims expressed by acquired skills and competences

Acquired knowledge: - student will be able to define basic technologies for molds and cores manufacture including developmental trends - student will be able to carry out basic testing of molding and core mixtures - student will be able to predict optimal kind of molding mixture for casting manufacture on the basis of cast alloy Acquired skills: - student will be able to apply their knowledge to the decision about the suitability of the molding mixture application with regard to the interaction of sand - binder - student will be able to apply their theoretical knowledge to suggestion of technology adjustment of preparation and application of materials for molds and cores manufacture

Teaching methods

Individual consultations


The subject is focused on theoretical and practical aspects of molding mixture Preparation, manufacture and utilization. Further, the attention is devoted to mutual interaction of individual molding mixture components and to developmental trends. Basic ways of molding mixtures testing is also presented here.

Compulsory literature:

Sand Binder Systems III - XIII. Foundry Management and Technology. Cleveland:Penton, 1995, roč. 124. ISSN 0360-8999 Mold & core test handbook. 3rd ed. Des Plaines: American Foundry Society, c2001-2006. ISBN 0-87433-228-1.

Recommended literature:

GOODRICH, G. M., ed. Casting defects handbook: iron & steel. Schaumburg: American Foundry Society, c2008. ISBN 978-0-87433-314-5.

Way of continuous check of knowledge in the course of semester

The completion of the interim tests. Oral exam.



Other requirements

Elaboration of semestral projects and completion of the interim tests


Subject has no prerequisities.


Subject has no co-requisities.

Subject syllabus:

1. Silica sands, chemical, mineralogical and size distribution evaluation, log - W - grain size criterion, optimal ratio of two fractions. Advantages and disadvantages of silica sand utilization. Collapsibility of sodium silicate molds. Coefficient of angularity, determination, its influence on physical properties of mixture, binder selection 2. Artificial non-silica sands, metallic and non - metallic sands. Chromite sands, its characterization, critical concentration of oxides (CaO, SiO2) grain surface changes due to thermal stress, selection of optimal binder for defined sand 3. Non - silica sand, classification, general characterization and possibilities of their utilization. Structure of molding mixture. Porosity and permeability of molding mixture. 4. Influence of temperature, sands, compactibility and ash parts on mold permeability. Thermo-physical properties of foundry mold. Thermal conductivity, methods of evaluation. Coefficient of thermal accumulation, constant of solidification and determination of solidification time (Chvorinov rule) 5. Kinds of sands surfaces, measurements and significance (theoretical, external, effective and specific surface). SiO2 surface activation, ways and function of activation. Sand reclamation, its ways and procedures. Control of mixtures quality with water glass and artificial resins, alternative ways of reclamation 6. Adhesion - Cohesion strengths of binders. Activation of artificial resins by silanization , influence of individual sands with different surface quality (reclaims). Structure and properties of clay binders (aluminosilicates). Clays at natural sands, clays of montmorillonitic type. Water function in clay minerals, kinds of water, determination of optimal moisture. Clay - water interactions. 7. Properties of bentonite molding mixture, its degradation due to thermal stress. Ionic exchange in bentonites, soda activation mechanism a chemism, advantages and disadvantages. Green sand system (JBS) and control of its properties. Oolitization, determination of oolitization degree, advantages and disadvantages. 8. Physical - chemistry parameters of JBS quality determination. Carbonaceous additives, coal pyrolysis and pyrolysis carbon (PC) formation. Function of semi-coke, lustrous (LC) and amorphous (AC) carbon. PC determination according to I. Bindernagel method, theory of LC. Optimal Concentration of PC in a mold, casting defects due to abundance and/or absence of PC. 9. Sodium silicates, their manufacture, basic parameters. Technologies with sodium silicate. Reversible and irreversible methods of sodium silicate hardening. Structure of colloidal solution, gelation process, ST - mixtures with ester hardening. Collapsibility of mixtures with sodium silicates and its solution. 10. Reclamation of mixtures with sodium silicates, criteria of reclaim quality (total and soluble amount of Na2O, critical concentration of acetates) and their influence on technological properties of mixtures. Renaissance of mixtures based on sodium silicates (technology Cordis, AWB, Clean Cast, INOTEC). Technology of salt cores preparation, manufacture and utilization. Review of binders based on phenol-formaldehyde resins. Basic classification of technologies according to preparation way (C - Method, HOT - BOX, COLD - BOX resole). 11. Preparation of shell mold, its manufacture, defects, reclamation and combination with green sand system. Developmental trends. HOT-BOX technology and its developmental trends (HB Plus, Warm-Box, Thermoshock). PUR COLD-BOX technology. Physical-chemistry process of hardening. Choice of silica sand, influence of moisture (isocyanate degradation). Types of tertiary amines. Collapsibility and reclamation of mixtures 12. Advantages and disadvantages of Alpha and Beta SET, PEP-SET technology. Principles of hardening, reclamation. Chemistry of furan binders. Type of binders for steel and iron castings (nitrogen pinholes). Function of furfuryl alcohol content at binders. Function of water at binder and in molds (polycondensation reaction of hardening). Technologies based on furan binders (HOT-BOX, SO2 - process). Advantages and disadvantages. Reclamation, Principle of SO2 -process 13. ST - furan mixtures. Types of acid catalysts. Influence of components temperature on run and velocity of process. Reclamation with utilization of multistage magnetic separation. Quality of chromite reclaims. Hardening principle of CO2 - resol technology. Comparison with CO2-sodium silicate technology. Advantages and disadvantages. Carbohydrate as binders and as additives of green sand systems 14. Binders of the 3rd generation. Magnetic mold, Vacuum method, EFF-SET Process, LOST FOAM, Replicast, principle, utilization, advantages and disadvantages of these technologies. Surface protection of molds and cores. Sprayings, coatings. Binders of the 4th generation.

Conditions for subject completion

Conditions for completion are defined only for particular subject version and form of study

Occurrence in study plans

Academic yearProgrammeField of studySpec.ZaměřeníFormStudy language Tut. centreYearWSType of duty
2021/2022 (N0715A270010) Metallurgical engineering Tec P English Ostrava 1 Compulsory study plan
2020/2021 (N0715A270010) Metallurgical engineering Tec P English Ostrava 1 Compulsory study plan
2019/2020 (N0715A270010) Metallurgical engineering Tec P English Ostrava 1 Compulsory study plan

Occurrence in special blocks

Block nameAcademic yearForm of studyStudy language YearWSType of blockBlock owner