A wide variety of water-soluble cores are widely used in hollow composite castings with internal cavities, curved channels, and undercuts. Among them, the cores made by adding binders of inorganic salts in the form of aqueous solutions have excellent solubility in water. However, excellent collapsibility is often accompanied by poor moisture absorption resistance. In this study, a water-soluble core with moderate strength and moisture absorption resistance was prepared by hot pressing and sintering the core sand mixture of sand, bentonite, and composite salts, and a tee tube specimen was cast. The experimental results showed that the cores with KCl-K2CO3 as binder could obtain strength of more than 0.9 MPa and still maintain 0.3 MPa at 80±5% relative humidity for 6 hours; the subsequent sintering process can significantly improve the resistance to moisture absorption of the hot pressed cores (0.6 MPa after 24 hours of storage at 85±5% relative humidity); the water-soluble core prepared by the post-treatment can be used to cast tee pipe castings with a smooth inner surface and no porosity defects, and it is easy to remove the core.

Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as

SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry

machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of

specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and

consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and

spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel

exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in

second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g

for base steel