News Center
15
2021
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02
Foundry: What are the reasons for the excessive carbon content in castings? (Part 1)
Foundry
Foundry: The following are the reasons for the carbon content of castings exceeding the standard: 1. The selection of pattern materials for castings is unreasonable. In the selection of white pattern materials for castings, one is the high carbon content; the other is the high density of the white pattern. This results in a high carbon content during the thermal decomposition of the casting pattern during the pouring process, which increases the liquid phase and mist-like free carbon content during the pouring and filling process of the casting, increasing the carburization probability of the cast steel parts.
Foundry: Causes Casting Several reasons why the carbon content of the part exceeds the standard
1. The pattern material selection for the casting is unreasonable. In the selection of white pattern materials for castings, one is high carbon content; the other is high white pattern density. This results in a high carbon content during the thermal decomposition of the casting pattern during the pouring process, which increases the probability of carburization of the steel casting due to the high content of liquid and atomized free carbon during the pouring and filling process of the casting.
2. The carbon content in the production smelting batching of steel castings is not strictly controlled, especially the carbon content in various scrap steels and whether there are other alloy components in various scrap steels are unknown.
3. The pattern assembly has many bonding surfaces. Poor quality of pattern assembly parts, and the assembly surface is not smooth and flat, resulting in an increase in the amount of glue used during pattern assembly and bonding, which increases the carbon content of its thermal decomposition products.
4. In Casting the pouring system setting of the casting, the pouring and filling design is unreasonable. Because the carbon content of steel casting products is low when producing low-carbon steel castings, if the pouring and filling method of the casting is not reasonably designed, the probability of carbon diffusion from the thermal decomposition products of the casting pattern into the casting increases, resulting in carburization and carbon increase.
5. The selection of white mold adhesive is unreasonable. First, there are no requirements for the material quality and composition content of the adhesive, and an adhesive with a high carbon content is used; second, the adhesive ability of the selected adhesive is poor, resulting in a large amount of glue used during white mold assembly and bonding; this increases the carbon content of the thermal decomposition products of the adhesive during the pouring process, which increases the carburization probability of steel castings.
6. Foundry : The coating layer of the casting pattern and the molding sand in the pouring sand box have poor air permeability. This will cause the thermal decomposition products of the pattern and pattern assembly adhesive to meet the pouring steel liquid for pattern thermal decomposition during the casting production and pouring process, and cannot be quickly discharged from the pouring cavity, creating unfavorable working conditions and conditions for carburization and carbon accumulation.
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Shandong Gongchen Machinery Technology Co., Ltd.
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