Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: przyczyny wad

Sortuj według:

Ogranicz wyniki do:

The Process of Vacuum Formation in the Shrinkage Cavity at Castings Crystallization

Khrychikov V., Semenov O., Meniailo H., Aftandiliants Y., Gnyloskurenko S.

Archives of Foundry Engineering

2022

Vol. 22, iss. 4

79--84

The formation process of one of the most common casting defects, a shrinkage depression concerned to shrinkage cavity, was studied. The methodology, device and the experimental set up were developed to study the shrinkage cavity growth. The kinetics of vacuum formation in the cavity of the spherical casting of Al-Si-Mg alloy at its solidification in the sand-and-clay form was investigated. The data were analysed taking in mind the temperature variation in the centre of crystallizing casting. The causes of the shrinkage depression in castings were clarified. It was determined that atmospheric pressure leads to the retraction and curvature of metal layer on the surface of the casting with lower strength below which the shrinkage cavity is formed. To avoid such defects it was recommended to use the external or internal chills, feeders and other known technological methods. Deep shrinkage cavities inside the castings could be removed with an air flow through a thin tubular needle of austenitic steels for medical injections.

Evaluation of the Cause and Consequences of Defects in Cast Metal-Ceramic Composite Foams

Popielarski P., Sika R., Czarnecka-Komorowska D., Szymański P., Rogalewicz M., Gawdzińska K.

Archives of Foundry Engineering

2021

Vol. 21, iss. 1

81--88

In this research, the quality of manufactured cast metal-ceramic foams (manufactured using blowing gas) was tested. The causes responsible for defect formation in the composite foams and their consequences were analyzed using the FMEA (Failure Mode and Effects Analysis) method, which is a useful tool for minimizing losses caused by low product quality. This method involves analytically determining correlations between the cause and consequences of potential product defects, and it takes into account the criticality factor (risk). The FMEA analysis showed that pore breaks were the most "critical defect" (with the highest number of effects on the product, the Risk Priority Number, affecting the quality of the composite foam). The second most critical defect was discontinuities in the foam frame structure. Destruction or damage to the foam structure (although very rare) deprived the composite foam of its primary function, which is to reinforce the product. The third most critical defect was non-uniform foam pore size.

Odwęglenie a wady powierzchni główki szyny

Mikłaszewicz I.

Problemy Kolejnictwa

2014

Z. 165

85--96

Za pomocą pomiaru twardości badano wielkość odwęglania powierzchni tocznej nowych szyn. Dokonano przeglądu powstających podczas eksploatacji wad powierzchniowych główki szyny powiązanych z odwęgleniem. Opisano prawdopodobne przyczyny tworzenia się wad typu nadpęknięcia krawędziowe główki oraz wady falistości, mające związek z odwęgleniem powierzchni tocznej szyn, jak również możliwości zapobiegania występowaniu tych wad. Badania przeprowadzono na podstawie wymagań ujętych w normie PN EN 13674-1:2011 [6] oraz „Warunkach Technicznych Id-106:2010” [8].

The size of the decarburization of the head rails has been tested by means of hardness measurement. The overview of defects, taking place during exploitation process, connected with decarburization. Shows a possible reason of creation of (head check) defect and waves of rail surface connected with decarburization and method of limitation of this defects. The test curried out on demands, according with the PN EN 13674-1:2011 norm and Warunków Technicznych Id-106:2010.