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How to avoid water marks on the surface of copper castings

Update:30 May 2019
Summary:

Copper castings are precision castings. If you are not […]

Copper castings are precision castings. If you are not careful during the casting process, some surface defects will occur. Water marks are one of them. The main reason for the appearance of water marks on the surface of copper castings is that the moisture content of the sand is too high or the weather is cold and the temperature is too low. How should we avoid this problem during the casting process:

1. Control sand water: 4~5 Improve sand permeability 120~170 Sand compaction rate control Under the premise of ensuring quality requirements, the amount of gasification materials should be strictly controlled. For example, the amount of coal powder added can meet the requirements. Just fine, master the pouring temperature

2, control the amount of clay, sand mixing must be uniform mixing time for dry mixing and wet mixing, dry mixing time 3 to 4 minutes, wet mixing time should be 7 to 9 minutes, then emphasize the importance of dark pores, because this Phenomenon we often met, no less reason to find the last problem and the problem was solved.

3, strict control of the water content of the original sand, the requirements must be dry, the amount of water added in winter is 2.5% -3.5%. If the repaired parts need to be sprayed with water, repaired and dried with the wind, in winter, it is best to heat the sand and timely pouring, or Increase the room temperature and do more darkness. Other reasons do not have to be considered.

In addition to the water ripple phenomenon, some other problems are likely to occur during the casting process of copper castings. We should analyze the specific problems in detail so as to take corresponding reasonable measures to solve them.