###### Abstract  
In this study, isotropic coke and coal tar pitch were subjected to compression molding while varying the compression pressure and holding time. As a result, carbon blocks were fabricated, and their mechanical properties and microstructure were analyzed, with respect to applied pressure and holding time. The compression pressure was set to 70, 100 and 130 MPa, while the holding time was set to 1, 2 and 3 min. Overall, with an increase in compression pressure, bulk density increased while porosity decreased. Increased compression pressure also led to enhanced mechanical and electrical properties. Microstructural analysis confirmed that, after compression molding granules that were larger than existing kneaded particles appeared. The formation of granules is attributed to the tendency of kneaded particles to connect and coalesce with each other under applied pressure during the compression molding process. As the compression pressure increased, the proportion of granules in the microstructure increased while the size of pores decreased. This phenomenon can be attributed to kneaded particles coming closer to each other under applied pressure. At a compression pressure of 130 MPa, both bulk density and porosity increased with a longer holding time. Some pores existed within granules, while others protruded out of granules, thereby forming long channels of connected pores around them. This microstructural change was considered to result in degraded mechanical and electrical properties.  
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method depends on the intended purpose and usage [9]. Compression molding is a process in which the target material is injected into a mold with a specific shape, and pressure is applied in a uniaxial direction for forming. This forming process is relatively simple and quick, but the friction between the material and the mold, induced by the applied pressure, may result in less uniform density across the matrix [1; 10]. With compression molding, the applied pressure, holding time, and temperature are varied to suit the expected properties of the resulting products. With an increase in the compression pressure, the density also increases; however, as the pressure exceeds a certain threshold, the rate of increase in density slows down [11]. As such, both the pressure and holding time applied during compression molding significantly affect the ultimate properties of the final products. Consequently, it is critical to find optimal process conditions tailored to target materials.  
There are a few studies about the manufacturing conditions for producing graphite blocks. [PERSON] et al. [12] reported the effect of the average particle size of coke on the microstructure and properties of graphite blocks; [PERSON] et al. [13] reported the relationship between kneading and carbonization temperature and properties during the manufacture of carbon blocks. In previous studies by the authors of the present study, the porosity of bulk graphite fabricated using compression molding, along with the mechanical properties of graphite blocks fabricated with CIP, were examined [14; 15]. However, it is difficult to find studies about holding time and pressure during uniaxial pressurization for manufacturing graphite blocks.  
In this study, carbon blocks were fabricated via compression molding, using coal-based isotropic coke as a filler and coal tar pitch as a binder. The study then analyzed the effects of the applied pressure and holding time during compression molding on the mechanical properties and microstructure of the resulting carbon blocks.