How can foundries reduce the scrap rate and what is the national standard for the foundry scrap rate

This is a more systematic question!

First of all, in terms of the casting performance of the part, for those places that are not too important and can be modified, improve the structure, and then be able to have better castability!

Then, in terms of casting process, there are many ways to cast, and choosing other casting methods may be very effective for this. If you use sand casting, then the thickness of the sand (tightness of the sand mold), water content (air permeability), sprue setting, pouring temperature, metal composition are required. If it is pressure casting, it is also related to the filling pressure.

To sum up, there are two main points: the casting process of the part and the selection of the casting process.

In the case that the parts cannot be changed, the main thing is the improvement of the process. There is nothing for the rest!

Judging by your introduction, you are doing quality assurance. If we talk about the concept of quality assurance;

Your article can be summarized from the statistical classification of defects, types, and distribution of waste products, as well as the production status at that time, the parameters controlled by each process, and the variation. Submit to the technical department and be solved by the production engineer or technical engineer.

As for the problem you introduced, since I don't know your production status, as mentioned on the first floor, it is a more systematic problem.

As; Air leakage, can you tell if the air leak is due to air holes? Slag holes? Shrinkage? Caused?

This way you can address it in a targeted manner.

Sticky sand, mechanical sticky sand? Chemical sticky sand? If the degree of scrapping is caused, the strengthened shot blasting can no longer be solved.

Pay attention to the pouring temperature and the compaction rate of the molding sand. Don't adjust the process first, first find the problem from the process control.

Summary. However, relevant reports also show that many foundry enterprises in China still use backward casting production technology, and lack of necessary experimental and testing methods, resulting in a high casting rejection rate and large processing allowance. The waste rate of foundry enterprises in China is generally 7%-15%, and some enterprises even exceed 20%, while the casting waste rate in advanced countries is generally about 2%-3%.

The weight of China's cast Russian gross is 10%-20% heavier than the average weight of foreign countries, and the processing allowance is large, which not only wastes raw materials but also increases direct production energy consumption.

Hello, dear! Thank you for your patience <>

I am a small durian with a loss of life, and I am happy to answer your question: there is no definition of the scrap rate in the casting national standard, but the default is the ratio of the number of scraps to the overall quantity.

However, relevant reports also show that many foundry enterprises in China still use backward casting production technology, and lack of necessary experimental and false detection methods, resulting in a high casting rejection rate and large processing allowance. The waste rate of China's foundry enterprises is generally 7%-15%, and some enterprises even exceed 20%, while the waste rate of Bu Zhengran castings in advanced countries is generally about 2%-3%: China's casting Russian gross weight is 10%-20% heavier than the average weight of the country, and the processing allowance is large, which not only wastes raw materials but also increases direct production energy consumption.

The calculation is as follows:

1. Calculated by weight.

Casting scrap rate = (casting scrap output total casting output) x 100% Second, calculated by quantity.

Casting scrap rate = (number of castings scrap total number of castings) x 100%.