Precision casting surface defect definition
An increase in the quality requirements of the casting […]
An increase in the quality requirements of the casting will result in a reduction in the machining allowance and a reduction in the amount of defects. Therefore, certain heat-resistant steel precision castings that were previously cast in air or vacuum and were considered to be qualified are now judged to be waste. Typical examples of such cases are surface defects of heat resistant steel and corrosion resistant steel castings, a defect known in the past as "corrosion".
In actual production, it is often necessary to analyze casting defects, the purpose of which is to find out the cause of the defects so that measures can be taken to prevent them. For precision casting designers, understanding product defects and causes can help to properly design the casting structure and combine the actual conditions of the casting production to properly formulate the technical requirements.
There are many defects in precision castings, and the defects and causes are very complicated. Sometimes, defects caused by many different reasons appear on the same casting, or the same reason may cause various defects when the production conditions are different.
Whether a defective casting with defects is classified as waste must be determined according to the use and requirements of the casting and the location and severity of the defect. Under normal circumstances, there are minor defects that can be used directly; there are medium defects, which can be used after repair; if there are serious defects, they can only be scrapped.