Improve Your Vacuum Test: The results of a vacuum test for aluminum melt quality are only as good as the accuracy of the test itself

摘要

Of all the customer reasons for returning finished castings, porosity is the leading cause of rejection. The varied causes for porosity include contained inclusion matter, dissolved hydrogen in the melt, shrinkage, air-or mold/core-generated gases trapped in the pouring stream, and combinations of all of the above. Once the true cause of the porosity has been determined, the task becomes one of evolving and implementing solutions through process modifications. This ultimately will include testing to ensure the manufacturing processes remain free of the conditions causing the porosity.