Refinement is one of the most energy consuming technological process, aimed at obtaining mineral raw materials of the proper grain size.

Cast structural elements such as jaws or hammers in crushing machines operate under conditions of an intensive wear. The data indicate

that 80 % of failures of machines and devices is caused by wearing of rubbing surfaces. This problem became the subject of several

scientific and industrial investigations carried out in the whole world in order to produce materials ultra- wear resistant. Methods allowing

to obtain wear resistant composite castings are discussed in the hereby paper. Within the performed research microstructures of the

produced composite zones were presented and the comparative analysis with regard to mechanical and functional properties of local

composite reinforcements in relation to the commercial alloys of increased wear resistance was performed. The results show almost twenty

five times increase in wear resistance compared to manganese cast steel containing 18 % Mn.

The influence of boron carbide and tungsten carbide on the apparent porosity, density, coercive force, hardness and microstructure of metal matrix composite of the Ferro-TiC type, is presented in this paper. The samples of investigated steel/titanium carbide composite were produced by powder metallurgy process, i.e. by powders mixing and compacting followed by sintering in the vacuum furnace. According to the results, steel/titanium carbide composite materials with addition up to 11.9 vol.% of boron carbide are interesting to detailed investigation as well as materials having more than 17.2 vol.% of tungsten carbide because these compositions show significant changes in hardness and coercive force values.

The study presents the results of research on the development of composite zones in castings based on the intermetallic phase of Ni3Al. Composite zones were obtained by placing packets with substrates for the reaction of titanium carbide in a foundry mould. To provide a variable carbides content in the composite zone, two compositions of the packets were prepared. The first packet contained only substrates for the reaction of TiC synthesis; the second one also contained a filler. The resulting composite zones in castings were examined for the filler effect on changes in the volume fraction, size and morphology of carbides in the zone. In addition, the effect of filler on the mechanical properties of the zone was verified, observing changes of Vickers hardness in this area. It was found that the presence of filler in the composition of the packet for synthesis reduced the content of carbides, as well as their size and morphology. Lower surface content of carbides reduced hardness of the zone, which enabled smooth control of the mechanical properties. At the same time, the use of the selected filler did not disturb the course of the TiC carbide synthesis.

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

In this study, low-carbon cast steel was reinforced with TiC by SHS-B method, also known as combustion synthesis during casting method. The composite zone was then subjected to surface remelting by Gas Tungsten Arc Welding (GTAW) method. The remelting operation was realized manually, at 150 A current magnitude. Microstructure, phase composition and hardness of remelted zone were investigated. XRD results reveal that the phases of the composite zone in initial state consist of TiC and Feα. Surface remelting resulted in formation of thick layers containing TiC carbides, Feα and Feγ. Microstructural examination has shown strong refinement of titanium carbides in remelted zone and complete dissolution of primary titanium carbides synthetized during casting. The average diameter of carbides was below 2 μm. The structural changes are induced by fast cooling which affects crystallization rate. The hardness (HV30) of the remelted layer was in the range between 250 HV and 425 HV, and was lower than hardness in initial state.

In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by

means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of

the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive

infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy,

using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of

composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese

cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ballon-disc

wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in

the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base

alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the

composite zone was five times lower than chromium white cast iron containing 20 % Cr.

This study presents an analysis of aluminium cast iron structure (as-cast condition) which are used in high temperatures. While producing casts of aluminium iron, the major influence has been to preserve the structure of the technological process parameters. The addition of V, Ti, Cr to an Fe-C-Al alloy leads to the improvement of functional and mechanical cast qualities. In this study, a method was investigated to eliminate the presence of undesirable Al4C3 phases in an aluminium cast iron structure and thereby improve the production process. V and Ti additions to aluminium cast iron allow the development of FeAl - VC or TiC alloys. In particular, V or Ti contents above 5 wt.% were found to totally eliminate the presence of Al4C3. In addition, preliminary work indicates that the alloy with the FeAl - VC or TiC structure reveals high oxidation resistance. The introduction of 5 wt.% chromium to aluminium cast iron strengthened the Al4C3 precipitate. Thus, the resultant alloy can be considered an intermetallic FeAl matrix strengthened by VC and TiC or modified Al4C3 reinforcements.