In the specific type of casting, sand casting will be involved below. Now let's learn together.
1. In sand casting, which kind of foundry sand is used more? In addition, what is the specific role of sand binder?
In sand casting, siliceous sand is often used as the foundry sand. Moreover, if the high-temperature performance of siliceous sand can not meet the requirements of use, then these special sands such as zircon sand, chromite sand or corundum sand can be used. The specific function of molding sand binder is to bond loose sand particles into molding sand, so that casting work can be carried out smoothly.
2. What are the main chemical hardening in sand casting?
The chemical hardening in sand casting is mainly for:
1）Self-hardening: when adding sand, add binder and hardener. In this way, the sand mold or core will harden by itself after it is made.
2）Gas mist hardening: no hardener is added during sand mixing. After modeling or core making, gaseous hardener or atomized liquid hardener is blown in.
3）Heat hardening: when mixing sand, add latent hardener that does not work at room temperature. After the sand mold or core is made, it is heated to allow the latent hardener to function and become an effective hardener.
3. If the quality of molding sand is not good, will it adversely affect the castings obtained by sand casting? In addition, what are the advantages of chemically hardened sand using resin as a binder?
Poor quality of molding sand will adversely affect the castings obtained by sand casting. For example, it will cause defects such as porosity, sand holes, sticky sand and sand inclusions in the casting. The advantage of chemically hardened sand using resin as a binder is that it is easy to separate the casting and molding sand after pouring, so that the cleaning of the casting can be reduced. At the same time, most of the sand can be recycled.