Core Post-Baking


To determine the effect of core baking on porosity elimination, several cores were subjected to post-baking or curing for 1, 2 and 4 hr.

Castings made with cores baked at 450F (232C) for 1 hr contained severe porosity defects. Intermediate times of 2 hr significantly reduced porosity. Baking for 4 hr at 450F (232C) produced a distinctive core color change to chocolate brown and had a significant effect on porosity elimination. Although such lengthy times may be impractical, higher baking temperatures or short times at high temperatures might be effective in reducing overall binder level in the core surface layers. Baking also demonstrates that some free hydrocarbons are volatilized, and N components from the Part II resin may undergo further reactions to form more stable compounds.

Table of contents
[Paper Header]
[Porosity Study]
[Binder Ratio] [Binder Level] [Casting Temperature] [Section Size]
[Sand Effect] [Iron Oxide Additions] [ Binder Dispersion/Mixing]
[Metal Composition] [Core Age]
[Eliminating Porosity]
[Ti and Zr Additions] [In-the-Mold Additions] [ Core Washes]
[Core Post-Baking]
[Discussion]