The core competitiveness of silicon nitride bonded silicon carbide products lies in their uniform microstructure and stable distribution of the bonding phase. The uniform dispersion of the bonding phase and the density of the green body are entirely dependent on precise control during the forming stage. The forming process must meet four core requirements: uniform density, dense structure, no delamination, and uniform dispersion of the bonding phase. It is necessary to ensure uniform density throughout the green body, with the final product's bulk density controlled at 2.6-2.8g/cm³ and the apparent porosity ≤15%, laying the foundation for the uniform bonding of silicon nitride and silicon carbide. At the same time, it is necessary to avoid delamination and agglomeration of raw materials during pressurization and prevent defects such as phase segregation, loose structure, peeling, and cracking after sintering. Additionally, the pressurization speed and holding time must be precisely controlled to adapt to the complex particle size distribution, difficult exhaust, and poor fluidity of the silicon nitride bonded silicon carbide mixture, avoiding residual pores in the green body that could lead to erosion and penetration, and structural failure during high-temperature service. Currently, the technical shortcomings of traditional forming equipment have led to common problems in the production of silicon nitride bonded silicon carbide products, such as uneven density, green body delamination, uneven dispersion of the bonding phase, large dimensional deviations, and low product qualification rates, seriously restricting the industrialization of high-end silicon nitride bonded silicon carbide products. Zhengzhou Haloong, relying on the third-generation permanent magnet synchronous servo direct drive core technology, has upgraded the HLDS series of CNC servo screw presses, specifically addressing the forming challenges of silicon nitride bonded silicon carbide products and creating dedicated forming equipment. With the core advantages of precise pressure control, flexible pressure transmission, and intelligent adaptation, it has established a benchmark for the quality of high-end silicon nitride bonded silicon carbide products.

Compared to ordinary refractory bricks, the forming difficulty of silicon nitride bonded silicon carbide products is significantly increased due to the composite nature of the raw materials. The mixture is composed of silicon carbide coarse powder, fine powder, and silicon nitride micro powder in precise proportions, with a large particle size range, poor fluidity, and difficult exhaust. Moreover, the density difference between silicon carbide and silicon nitride raw materials is relatively large (silicon carbide density is approximately 3.2g/cm³, and silicon nitride density is approximately 3.17g/cm³). During the forming process, delamination and agglomeration are highly likely to occur, and the precision requirements for the application force, pressurization speed, and holding time are extremely strict. It is necessary to achieve green body densification through precise pressurization and ensure the uniform dispersion of the silicon nitride bonding phase, while avoiding delamination and cracking of the green body due to rigid impact. At the same time, it is necessary to efficiently remove air from the mixture to prevent residual pores from affecting the product's erosion resistance and erosion resistance.

Zhengzhou Haloong has deeply studied the raw material characteristics, forming process logic, and industry upgrade demands of silicon nitride bonded silicon carbide products. With the core technology of permanent magnet synchronous servo motor direct drive + static pressure flexible pressure transmission + intelligent CNC system, it has specifically optimized the HLDS series of servo screw presses, comprehensively upgrading the equipment's precision, stability, and adaptability. It precisely matches the forming requirements of silicon nitride bonded silicon carbide products and has become the preferred equipment for mass production of high-quality silicon nitride bonded silicon carbide products, assisting refractory material enterprises in creating high-quality products suitable for high-temperature, strong erosion, and strong erosion working conditions.

Equipped with a core permanent magnet synchronous servo motor direct drive system, it completely eliminates the inefficient transmission structures such as traditional friction discs and clutches, with an extremely short transmission chain and zero energy loss during energy transmission. The pressure output is stable and controllable throughout the process. The equipment is equipped with Haloong's independently developed dedicated CNC pressure control module for silicon nitride bonded silicon carbide, which can digitally and precisely set the impact energy, pressurization speed, stepwise pressurization times, and holding time. The energy repetition control accuracy is ≤±1%, ensuring that the pressure for each forming process is highly consistent, completely eliminating quality deviations caused by manual operation and mechanical fluctuations. In response to the complex particle size distribution, difficult exhaust, and easy layering and agglomeration of silicon nitride bonded silicon carbide mixtures, a customized stepwise flexible pressurization process was developed. This process first lightly presses the loose raw materials to slowly expel the internal residual air, then gradually and steadily applies pressure layer by layer, and finally maintains a long-term pressure to shape the product. This ensures that all parts of the green body, including the center, edges, and corners, are uniformly stressed, with density fluctuations controlled within a very small range. At the same time, it effectively avoids the agglomeration of silicon nitride and the layering of raw materials, providing a solid foundation for the uniform bonding of the bonding phase during subsequent high-temperature sintering, and increasing the product qualification rate to over 99%.

The equipment adopts a fully enclosed static pressure screw, nut, and dedicated heavy-duty bearing transmission structure. During operation, a stable high-pressure oil film is formed for protection, achieving flexible and uniform pressure application and gradual pressurization. This completely avoids the severe impact force and stress concentration problems caused by traditional rigid pressurization. The pressurization process is smooth and gentle, with uniform and soft pressure transmission. It can not only fully expel the internal pores of the green body and disperse the agglomeration of silicon nitride, completely eliminating defects such as porosity, layering, and cracks, but also gently protect the activity of silicon carbide and silicon nitride particles, avoiding green body layering and cracking, significantly reducing the waste of high-cost raw materials, and effectively extending the service life of the mold, reducing material costs, and improving the production efficiency of the enterprise.

Breaking through the structural limitation of the fixed bottom dead center of traditional equipment, a stepwise forging forming mode is adopted. According to the material, size, and structural complexity (continuous casting nozzles, kiln furniture, lining bricks, special-shaped parts) of silicon nitride bonded silicon carbide products, as well as the density requirements, the stroke of the slider, the pressurization depth, and the applied pressure can be flexibly adjusted to precisely match the forming requirements of various silicon nitride bonded silicon carbide products, covering the full range of production scenarios for high-end refractories. There is no need to worry about the problems of uneven pressurization caused by deviations in raw material filling, differences in particle size distribution, and changes in the fluidity of the mixture. Combined with a rapid mold changing system, mold changing is convenient and efficient, perfectly adapting to the flexible mode of multi-variety and batch production, meeting the batch supply needs of high-end fields.

The equipment is equipped with a dedicated forming parameter database for silicon nitride bonded silicon carbide products, integrating the optimal forming process parameters for various specifications, different raw material ratios, and different density requirements. It covers the forming parameters of common products such as standard bricks, special-shaped parts, and high-strength anti-erosion products. Operators can retrieve them with one click, eliminating the need for repeated debugging and exploration, and significantly reducing the interference of human factors on product quality. All forming parameters can be permanently saved and reused in batches, ensuring that the density, porosity, and dimensional accuracy of each batch and each product are highly consistent, and the silicon nitride bonding phase is evenly dispersed, easily meeting the strict quality requirements of high-end fields at home and abroad, and helping enterprises smoothly open up the overseas high-end refractory market.

Compared with traditional friction presses, the Haloong servo screw press adopts an on-demand start-stop and sleep energy-saving intelligent mode. The servo motor only operates during the pressing process, and the standby state is completely zero energy consumption, with a comprehensive energy-saving rate of over 55%. This significantly reduces the electricity cost of producing silicon nitride bonded silicon carbide products, meeting the green and low-carbon development needs of the refractory industry. At the same time, the static pressure transmission structure has minimal wear, and is combined with a fully automatic forced lubrication system and an oil shortage alarm device, achieving maintenance-free operation, with a low failure rate and a service life far exceeding that of traditional equipment. The later maintenance cost is reduced by more than 40%, comprehensively compressing production, maintenance, and material costs, helping enterprises achieve a green, low-carbon, and efficient production model.

The equipment is equipped with standardized industrial communication interfaces, which can be seamlessly linked with automatic and precise feeding machines, closed-loop distribution machines, intelligent demolding machines, non-destructive testing equipment for green bodies, and constant temperature conveyor lines, building an automatic and intelligent forming production line for silicon nitride bonded silicon carbide products. It realizes unmanned control throughout the process from distribution, pressing, pressure maintenance, demolding to green body transfer and inspection, minimizing human intervention. This not only avoids damage to the green body caused by manual operation but also ensures forming accuracy and production efficiency. It supports remote monitoring, parameter adjustment, fault warning, and production data traceability functions, facilitating domestic and foreign customers to manage production progress and product quality in real time from different locations. It fully conforms to the global trend of intelligent, digital, and green transformation in the refractory materials industry, and helps enterprises build an intelligent production base for high-end silicon nitride bonded silicon carbide products.

Zhengzhou Haloong Machinery Co., Ltd. is a leading enterprise in the domestic electric servo screw press field. For 45 years, it has always focused on technological innovation in refractory material forming equipment, delved into the pain points of forming processes for high-end refractory materials such as silicon nitride bonded silicon carbide, and insisted on empowering the refractory material industry with customized technology. The Haloong HLDS series of CNC servo screw presses cover the full tonnage range from 200T to 1600T. According to the material, specifications, production capacity, density, and raw material ratio requirements of customers' silicon nitride bonded silicon carbide products, it provides one-to-one customized forming solutions, fully meeting the mass production needs of various products and adapting to the supply of refractory materials in different high-end high-temperature, strong erosion, and strong erosion fields.