## 5 An Example of Producing a High-Aluminum Cast Iron  
The study assumes the development of the simplest possible method of obtaining high-aluminum cast iron, which would not be prone to \"self-disintegration\". In earlier studies, a method of replacing aluminum carbide with another type of carbide, e.g., TiC, was developed. Figure 5 shows the changes in the microstructure that will be visible when we introduce the appropriate titanium content into the cast iron. The research shows that the degree of replacement of aluminum carbides with titanium carbides depends on the content of the introduced titanium (according to Equation (3)). \[\text{Ti}+\text{C}\rightarrow\text{TiC}, \tag{3}\]  
Reaction (3) shows that 1 g of titanium binds 0.25 g of carbon, which gives 1.25 g of TiC carbide. For the casting conditions, the \(\Delta\)G free energy of Al4C3 carbide reaction formation will be \(-\)96 kJ. On the other hand, the free energy of \(\Delta\)G0 reaction formation of TiC carbide is \(-\)166 kJ. Thus, with the minimum amount of titanium needed to replace the Al4C3 carbide, TiC carbide will appear in the structure. An experiment with the use of titanium as a carbide-forming element ended the initial period of searching for a method blocking the \"self-disintegration\" of a casting made of high-aluminum cast iron. For example, an industrial application was tested in the form of casting the so-called grate bars for a power boiler. The furnaces of power boilers have belt grades with fully mechanized feeding and cleaning. The grate surface is made of separate cast-iron grades. This method of construction ensures that the drive chain articulated links are remote from the \"heat\", and the gratings can be easily replaced. The fuel slides automatically from the co  
Figure 5: Precipitates of titanium carbides in SEM microstructure (**a**) and microstructure (LM) of high-aluminum cast iron with precipitates of titanium carbides (**b**). deck and moves along with it through the furnace. The grate bars are rotatably mounted in the pins in the so-called \"Holders\" attached to the grate chains. In the upper run, the grate strips overlap, while in the lower run they fall vertically, which allows them to clean from slag and ash. The mass of the burned fuel can be adjusted with the grate advance speed (max. 0.8 m/min.) and the thickness of the fuel layer, which (depending on the type of coal) is 50-150 mm. The grates in power boilers operate in very harmful conditions of use. The most unfavorable is the increased operating temperature, sometimes reaching 800 \({}^{\circ}\)C, and in some cases, e.g., in the event of a blower failure, much higher. The method of feeding the boiler by pouring solid fuel (coal), the hardness of which will affect the accelerated wear (\"abrasion\") of the grate bars, is also important. The chemical effect of sulfur contained in coal (max. 0.6%) on the grate material also has a considerable influence. For research purposes, two castings were made (Figure 6a,b). The first (reference) with the chemical composition presented in Table 1 and the second one in Table 2. After about 14 days, signs of spontaneous disintegration of the first grate were noticed (Figure 6c), while the second grate, containing titanium carbide precipitates, Figure 6d, functioned for five years; it did not disintegrate, maintaining its glossy surface. When developing the chemical composition of a casting, it should not be assumed that every mass of carbon in the molten alloy can be freely \"exchanged\" with carbide-forming elements. At high carbon concentrations, casting is expected to be thixotropic in nature even in the presence of elevated temperatures in excess of 1600 \({}^{\circ}\)C. Therefore, it was decided to change the structure of high-aluminum cast iron with another carbide-forming element, in this case, tungsten, which was assumed to affect the strength properties of the metal matrix of the cast iron.