In the lost foam casting process, the selection of the runner system has an important impact on the casting quality, production efficiency and environmental performance. In recent years, a new type of refractory paper casting runner system has gradually replaced the traditional ceramic runner in the field of cast iron and cast steel due to its unique performance advantages. This article will analyze in detail why this runner system can perfectly match the needs of molten iron casting.
High temperature matching: complete gasification without residue
The molten iron temperature (1300~1500℃) and the pulp gasification temperature (≥1200℃) are perfectly matched
The refractory paper casting runner uses a special high-temperature resistant cellulose material. When the high-temperature molten iron is injected, the runner can be completely gasified and decomposed, and no residue will be produced to block the cavity.
Compared with traditional ceramic runners: mechanical cleaning is required, which increases the process cost.
Excellent thermal shock resistance
The flexibility of pulp material can buffer the thermal shock of molten iron
Traditional ceramic runners are prone to cracking under the impact of high-temperature molten iron, while refractory paper casting runners have better thermal shock stability and can withstand the drastic temperature changes during molten iron pouring, ensuring the integrity of the runner structure and smooth flow of molten metal.
Optimize molten iron flow, reduce turbulence and oxidation
The inner wall of the runner is smooth and the flow resistance is small
The paper casting runner is precisely formed and the surface finish is better than that of the ceramic runner, which can significantly reduce the turbulence during molten iron flow and reduce the risk of oxidation slag inclusions.
Good thermal insulation performance
The low thermal conductivity of pulp material helps to maintain the temperature of molten iron and avoid premature cooling, which is particularly suitable for the production of thick-walled cast iron parts.
Environmental protection and cost advantages
100% degradable and pollution-free
The paper casting runner is made of natural cellulose material, which only produces CO₂ and H₂O after high-temperature decomposition, without harmful substances, and is in line with the trend of green casting.
Practical application cases
Automobile brake disc (HT250 cast iron)
After using the paper casting runner, the surface finish of the casting is improved and the porosity defect rate is reduced by more than 50%.
Hydraulic valve body (ductile iron QT500)
The stability of the pouring system is improved, and the process yield rate is increased by 15%.
Conclusion
The refractory paper casting runner system has become an ideal choice for molten iron lost foam casting due to its high temperature adaptability, excellent thermal shock stability, optimized flow characteristics and environmental advantages. As the casting industry’s demand for green manufacturing and efficient production grows, this runner technology is expected to be used in more high-temperature alloy casting fields.