发泡石膏铸型制备试验的影响因素  

Influencing Factors on Preparing Foaming Gypsum Mold

作　　者：樊振中[1] 洪润洲[1] 陈邦峰[1] 杜旭初[1] 罗传彪[1] 潘俊杰[1] 

机构地区：[1]北京航空材料研究院

出　　处：《特种铸造及有色合金》2012年第11期985-990,共6页Special Casting & Nonferrous Alloys

摘　　要：研究了发泡石膏铸型制备过程中各试验因素对石膏混合浆料胶凝硬化时间、室温抗压强度、流动半径和发泡率的影响。结果表明,石膏混合浆料的胶凝硬化时间与水料比成正比,石英粉、高岭土、硅藻土、NaCl和MgSO4石膏辅料的添加提高了石膏铸型的室温抗压强度。随着水温升高,石膏混合浆料的胶凝硬化时间、室温抗压强度、流动半径和发泡率均呈现先上升后下降的趋势。以十二烷基硫酸钠作发泡剂,在硬水环境下仍可以制得发泡率为80%的发泡石膏铸型。低搅拌速度短时间下,发泡剂难以发泡完全;长时间高搅拌速度下,气泡易破碎消失,在转速为2000r/min经4min搅拌时石膏发泡最好。根据试验工艺参数制得了发泡石膏铸型并进行了热烘烤,在715℃下浇注了ZL114A合金铸件,热烘烤过程中发泡石膏铸型无开裂,同时铸件满足实际使用要求。Influences of experiment factors on the concretion hardening time, compressive strength at room temperature, flowing radius and foaming capacity in the process of producing gypsum slurry were investigated. The results show that the concretion hardening time of gypsum slurry is proportional to the ratio of water to powder, and the compressive strength of gypsum slurry is improved with adding quartz powder, kaolin, diatomite, sodium chloride and anhydrous magnesium sulfate at room temperature. With the water temperature increases, the concretion hardening time, compressive strength at room temperature, flowing radius and foaming capacity of gypsum slurry exhibit the trend of first decrease and then decrease. Foaming gypsum mold with 80% foaming rate can be made in hard water environment by adding sodium dodecyl sulfate as the vesicant. The foaming of vesicant is inadequate under lower stirring speed and time, while bubbles are easily broken away at high speed stirring and time. The desirable mixing process parameters are 2 000 r/min and 4 min. Foaming gypsum mold was produced based on the optimized process parameter, and then thermal baking was conducted. ZL114A alloy castings were poured at 715 ℃. The results reveal that the parts meet the actual requirements together with broken absence of the foaming gypsum mold in the process of baking.

关 键 词：石膏铸型 发泡 影响因素 

分 类 号：TG241[金属学及工艺—铸造]