The problems with steel foundries in China

There are three kinds of steel foundries in China. One is the sand casting foundries, then the water glass investment steel casting workshops, and the silica sol investment steel casting workshops. We usually called the investment casting as precision casting process.  

What kinds of products can these casting workshops produce?

As for the sand casting workshop, they usually make the steel castings with material of normal carbon steel, and some kinds of alloy steel. The prefer weights are from 5kg to 400kg. With normal surface and inside quality requirements, and simple machining. They usually use the green sand or CO2 gas hardening sand as the materials. The problems with these foundries are their production efficiency is low. Since they use the traditional manual molding process, their annual output is small. They can not meet the delivery time for the large orders. Second problem is their surface quality is not good. This is the common problem for all sand castings. Thirdly, they can not do the high precision machining. These workshops are usually able to make the simple machining. Of course, I do not mean all the steel foundries do not have CNC centers. Some large steel foundries have many good machines for machining. 

As for the water glass investment casting workshops, they use the water glass and yellow wax as the material. We also call this casting process as lost wax casting process. This process can keep very good dimensional and surface requirements, and these workshops usually use the medium-frequency induction furnace, therefore, they can make some alloy steels. Their problems are they can not make large or heavy castings. Their prefer size is between 50mm to 300mm, and prefer weight is between 0.3kg to 5kg. This is restricted by the lost wax process.  

As for the silica sol investment steel casting workshops, they use the materials of yellow wax and silica solution. So, they can keep the higher level for the surface quality and dimensional requirements. According to the experience of Mr. Galen Wang from Dandong Ruiding Foundry, the silica sol investment casting process can reach the best surface quality and dimensions. Their problems are as same as the water glass investment casting process. They have size and weight restriction. In addition, their production costs are usually three times of water glass investment castings. Therefore, unless you need absolutely high surface quality and dimensions, this process is not your best choice.

By the way, all steel foundries are not willing to make iron castings. It is because the pig iron used for making steel castings is not same as that used for making iron castings. We call this pig iron as steel pig or pig iron for steel making.  

We hope this article can help the overseas buyers and purchasers to learn more about the steel foundries in China, so, they can choose the most suitable suppliers for their products.  

Writer: Mr. Galen Wang from Dandong Ruiding Foundry.

For more articles, please check Dandong Foundry Blog.

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