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本报告介绍两种自硬粘结剂的比较结果。(低氮呋喃树脂和油—尿烷树脂)。讨论的中心是不同的砂子,热压强度和发气性问题。控制催化剂的加入量,使自硬砂的起模时间在45—60分钟的范围内,然后测定它们24小时的抗压强度。与尿烷树脂相比,呋喃树脂能在它和砂子的交界面上产生较高的粘结力,而且比较容易润湿砂子的表面。为了减少树脂的加入量,树脂砂使用的原砂,建议采用一种干式再生砂,这种干式再生砂在砂子的表面上残留一层光滑的树脂膜。根据树脂在1000℃分解之后的残留含炭量,可以推测尿烷树脂的热强度比较低。残留含碳量是根据树脂在1000℃分解生成的气体组成中计算出来的。与尿烷砂芯相比,呋喃砂芯含水分较高,(推算50％),氢气和碳氢化合物在分解气体中的含量较低。在1200℃时,尿烷树脂砂芯在4分钟内的发气量为总发气量的90％,而呋喃树脂砂芯在4分钟内的发气量的50％。在400℃时,尿烷树脂砂芯在8分钟内的发气量只有总发气量的40％,而呋喃树脂砂芯在8分钟内的发气量达总发气量的80％。
This report presents the comparison of two self-hardening binders. (Low-nitrogen furan resin and oil-urethane resin). The center of the discussion is the different sand, hot compressive strength and gas problems. The amount of catalyst added was controlled such that the mold release time for self-hardening sand was in the range of 45-60 minutes and then their compressive strength for 24 hours was measured. Compared with urethane resin, furan resin can produce high adhesive force on the interface between it and sand, and wet the surface of sand more easily. In order to reduce the amount of resin added, raw sand used for the resin sand is recommended to use a dry recycled sand, which has a smooth resin film remaining on the surface of the sand. Based on the residual carbon content after the resin is decomposed at 1000 ° C, it can be estimated that the urethane resin has a relatively low thermal strength. The residual carbon content is calculated from the gas composition of the resin decomposed at 1000 ° C. Compared with the urethane sand core, the furan sand core contains a higher water content (50% of the estimated value), and the content of hydrogen and hydrocarbons in the decomposed gas is lower. At 1200 ° C, the urethane resin sand core generated 90% of the total gas evolution in 4 minutes, while the furan resin core produced 50% of the gas evolution in 4 minutes. At 400 ℃, the urethane resin sand core has only 40% of the total gas evolution in 8 minutes, while the furan resin core generates 80% of the total gas evolution in 8 minutes.