The roasting of clay pipe brick is the key link of brick making process. Generally, the baking temperature is controlled between 900-1100 ℃, so that the brick can be partially melted and sintered.

If the baking temperature is too high or the time is too long, it is easy to produce over fired bricks.

The characteristics of over fire brick are deep color, crisp knocking sound, large deformation, etc.

If the baking temperature is too low or the time is not enough, it is easy to produce underfired bricks.

The characteristics of underfired brick are light color, dumb knocking, low strength, high water absorption and poor durability.

When the brick is roasted in the kiln, it is an oxidizing atmosphere, and the brick is red due to the formation of Fe2O3, which is called red brick.