The exothermic insulating riser played an important role in the solidification process of metal liquid for the improvement of casting quality. This paper focused on the use of organosilicon slag to replace part of the aluminum powder as an exothermic agent for the riser, to reduce production costs and turn waste into treasure. The experiments firstly studied the effect of organosilicon slag content on the combustion temperature and holding time and determined the components of the riser exothermic agent and organosilicon slag. On this basis, the effects of the content of Na3AlF6 flux and alkali phenolic resin binder on the combustion heating time and strength properties of the riser were studied. And the ratio of mixed oxidants was determined by single-factor orthogonal experiments to optimize the addition of three oxidants, Fe3O4, MnO2, and KNO3. Finally, the performance of the riser prepared after optimization was compared with that of the riser prepared with general aluminum powder. The results showed that with the mixture of 21% organosilicon slag and 14% aluminum powder as the exothermic agent, the highest combustion temperature of the prepared exothermic insulating riser was 1451℃ and the holding time was 193 s; the optimal content of Na3AlF6 flux was 4%, and the best addition alkali phenolic resin binder was 12%; the optimized mixing ratio of three oxidants was 12% for Fe3O4, 6% for MnO2, and 6% for KNO3. Under the optimized ratio, the maximum combustion temperature of the homemade riser was 52℃ and the heat preservation time was 14% longer compared with the conventional exothermic insulating riser with 25-35% aluminum powder.

In modern times, there are increasing requirements for products quality in every part of manufacturing industry and in foundry industry it

is not different. That is why a lot of foundries are researching, how to effectively produce castings with high quality. This article is dealing

with search of the influence of using different types of risers or chills on shrinkage cavity production in ductile iron castings. Differently

shaped risers were designed using the Wlodawer´s modulus method and test castings were poured with and without combination of chills.

Efficiency of used risers and chills was established by the area of created shrinkage cavity using the ultrasound nondestructive method.

There are introduced the production process of test castings and results of ultrasound nondestructive reflective method. The object of this

work is to determine an optimal type of riser or chill for given test casting in order to not use overrated risers and thus increase the cost

effectiveness of the ductile iron castings production.

A new Computer-Aided Design approach is introduced for design of steel castings taking into account the feeding ability in sand moulds.

This approach uses the geometrical modeling by a CAD-program, in which the modul “Castdesigner” is implemented, which includes the

feeding models of steel castings. Furthermore, the feeding ability is guaranteed immediately during the design by an interactive geometry

change of the casting cross section, so that a directional feeding of the solidifying casting from the installed risers is assured.

Small additions of Cr, Mo and W to aluminium-iron-nickel bronze are mostly located in phases κi (i=II; III; IV),and next in phase α

(in the matrix) and phase γ2. They raise the temperature of the phase transformations in aluminium bronzes as well as the casts’ abrasive

and adhesive wear resistance. The paper presents a selection of feeding elements and thermal treatment times which guarantees structure

stability, for a cast of a massive bush working at an elevated temperature (650–750°C) made by means of the lost foam technology out of

composite aluminium bronze. So far, there have been no analyses of the phenomena characteristic to the examined bronze which

accompany the process of its solidification during gasification of the EPS pattern. There are also no guidelines for designing risers and

steel internal chill for casts made of this bronze. The work identifies the type and location of the existing defects in the mould’s cast. It also

proposes a solution to the manner of its feeding and cooling which compensates the significant volume contraction of bronze and

effectively removes the formed gases from the area of mould solidification. Another important aspect of the performed research was

establishing the duration time of bronze annealing at the temperature of 750°C which guarantees stabilization of the changes in the bronze

microstructure – stabilization of the changes in the bronze HB hardness.