The improvement of casting quality requirements will lead to the reduction of machining allowance, as well as the reduction of defects. As a result, some heat-resistant steel precision castings previously scratched in air or vacuum, previously considered acceptable, are now judged as scrap. Typical examples of such cases are surface defects in heat-resistant steel and corrosion-resistant steel castings, a defect that was acceptable in the past as "corrosion."
In actual production, castings often need to analyze defects, the purpose is to find out the causes of defects in order to take measures to prevent it. For the precision casting designer, understanding the product defects and their causes can help to design the structure of the castings properly, and appropriately define the technical requirements in combination with the actual conditions during the casting production.