A study was conducted on the effects of various influencing factors in the compound hardening process, including core box temperature, such hot-air parameters as temperature, pressure and blowing time, as well as micro-silica powder, on the tensile strength denoted as σ₀ of the prepared sand core after cooling to room temperature, on the basis of which the hardening mechanism of the micro-silica powder was revealed. The sand core was bonded using modified water glass. The single factor test was conducted to achieve the optimal compound hardening process for the sand core. According to the research results, the introduction of hot air improved the σ₀ of sand core significantly from 1.89 MPa to 2.20 MPa, in comparison with that hardened only by heating the core box. After the addition of micro-silica powder, the σ₀ of sand core was further improved to 2.58MPa. According to the results of SEM analysis, the Si atoms in the water glass contributed to improving the modulus of the water glass after the addition of micro-silica powder, thus promoting the water glass to gel when heated. As indicated by FT-IR analysis, the concentration of Si–O–Si bonds was increased as a result of the reaction occurring between micro-silica powder and water glass in the hardening process, implying that micro-silica powder can be effective in enhancing the polymerization of water glass.

研究了复合硬化过程中各种影响因素的影响，包括芯箱温度，温度，压力和吹塑时间等热风参数以及微硅粉对σ表示的拉伸强度的影响。冷却至室温后，将制得的砂芯取₀，由此揭示了微硅粉的硬化机理。使用改性水玻璃粘结砂芯。进行单因素测试以实现砂芯的最佳复合硬化工艺。据研究结果，引入热空气的改进了σ ₀与仅通过加热型芯盒而硬化的砂芯相比，砂型芯的显着性在1.89 MPa至2.20 MPa之间。在加入微二氧化硅粉末后，σ ₀砂芯的进一步提高到2.58MPa。根据SEM分析的结果，添加微硅粉后，水玻璃中的Si原子有助于提高水玻璃的模量，从而在加热时促进水玻璃凝胶化。如FT-IR分析所示，由于硬化过程中微硅粉与水玻璃之间发生反应，Si–O–Si键的浓度增加，这表明微硅粉可以有效地增强水玻璃的聚合。