Korotchenko

pp.1-14

A series of special experiments using castings of the simple configuration (slabs and bars) defines a value of the feeding zone of a butt end and makes it out as the regressional dependences of the feeding butt end zone on the characteristic sizes of this or that casting. Thus, considerable material and time expenditures are demanded to define the value of the feeding butt end zone to be used further, including calculation of directional solidification of castings. The paper offers a design procedure to calculate a zone of the feeding butt end via computing simulation of solidification in the casting mould thereby sharply reducing expenditures for searching the desirable values. To reveal spaces in the casting, staggered with shrinkable porosity, the new criteria of porosity developed in BMSTU are used. The paper shows a possibility to use the effective size as a characteristic parameter of casting for the regressional dependence of the feeding butt end zone thus providing this dependence universality and a possibility to use it for making any shaped casting, but not just the castings of a simple configuration.

This paper presents a new dimensionless criterion of formation of microporosity, which considers a set of essential technology factors, including atmospheric and metallostatic pressure, alloy’s gas saturation. The criterion is based only on the measured or controllable parameters and does not demand additional experimental data. A feature of the criterion is absence of the radius of a critical germ of a micropore. An estimation of the distance between secondary axes of dendrites is used instead. The criterion is recommended for using in systems of simulation of casting hardening for more accurate prediction of formation of microporosity.