 After the shakeout of the casting it is inspected for defects . The most common defects are misruns and cold shuts . These defects can be caused by cold dies , low metal temperature , dirty metal , lack of venting , or too much lubricant . Other possible defects are gas porosity , shrinkage porosity , hot tears , and flow marks . Flow marks are marks left on the surface of the casting due to poor gating , sharp corners , or excessive lubricant . 
