tutorial: engineering technology topic: castings defects prepared by: ing. elena nová projekt...
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Anglicky v odbornch pedmtech"Support of teaching technical subjects in EnglishTutorial: Engineering technology
Topic: Castings defects
Prepared by: Ing. Elena Nov
Projekt Anglicky v odbornch pedmtech, CZ.1.07/1.3.09/04.0002je spolufinancovn Evropskm socilnm fondem a sttnm rozpotem esk republiky.
Castings defects
Defects are divided according to activity where they originated:Defects at casting and solidifying Forming defects
Castings defects
Defects at casting and solidification
Slag inclusions At casting slag has not been retained -> surface faults, inner defects
Castings defects
Structure precipitation Casted material does not solidify equally (solidification goes from outside to inside) -> on a thicker walls maybe created cavities, -> called shrinkages (these will not happen if the casting walls are of equal thickness).
Babbles in casting structure Wet forming sand releases hydrogen and oxygen at the cast temperature and if not properly removed the gasses will enter the structure of the castingCastings defects
Cast tearing Diameter of transitions have been constructed too short (solidification of thicker parts have been slower) -> a bigger metal cooler parts are inserted into moulds with bigger diameter -> managing of cooling process Segregation Starts segregating of casted parts at solidification and uneven distribution of alloying parts -> different properties of material inside and outside of the cast. Castings defects
Residual stress Shrinkage cavity is hollow parts initiated at the cooling process.
Castings defects
Faults initiated at forming
Offset, reject casting Is caused if forms dont matched exactly Edge or oval thickening if the form is not sufficiently rammed -> hydrogen and oxygen recede under the casted material pressure. Castings defects
strojirenstvi.studentske.cz/2008/10/kontrola-vady-odlitk.htmlUsed literature
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