With the development of my country's foundry industry and the improvement of foundry technology, customers have higher and higher requirements for foundry factories. We have always been adhering to the customer first business philosophy, and strive to meet customer needs. Many customers who are not very familiar with castings do not understand the appearance defects of the products, and take it for granted that the casting products should be defect-free. Today, I will mainly talk about the appearance quality judgment standard of the casting blank of the silica sol process.

1. Cold barrier-The reason for the formation of cold barrier is generally the low temperature of molten iron and slow pouring speed. As a result, where the structure of the casting is relatively small, the molten steel will condense before the mold shell is fully filled, resulting in casting defects of the small structure. The cold barrier will reduce the strength of the casting, affect the mechanical properties of the casting, and even break the casting in severe cases. Therefore, our silica sol castings absolutely do not allow the cold barrier to exist on the surface of the casting.

2. Cracks-The reason for the formation of cracks is that in the process of solidification and shrinkage of the casting, the shrinkage is blocked due to the inconsistent cooling rate of each part. When the resistance exceeds the strength limit of the material, the casting cracks. The hazard of cracks is similar to that of cold insulation, and it will also reduce the strength and mechanical properties of the casting. Therefore, cracks on the surface of the product are not allowed to be accepted.

3. Insufficient pouring—Insufficient pouring of castings is generally due to the complex structure of the castings and the small passages in the mold shell, which leads to insufficient flow of molten steel in some places. Insufficient pouring seriously affects the appearance of castings, so it is also a defect that is absolutely not allowed to be accepted

4. Perforations—The perforations include pores, sand holes and shrinkage holes. Without affecting the performance of the casting, we are allowed to accept 1 perforation with a diameter of 0.5mm and a depth of 0.5mm within the range of Φ50mm. Exceeding one is regarded as unqualified.

5. Succulents-Succulents are mainly manifested as iron beans, flashes and bulges on the surface of castings. Succulents generally do not affect the strength of the castings. Flashes and bulges are not allowed on the surface of our silica sol castings! Without affecting the assembly performance of the casting, we are allowed to accept 1 iron bean with a diameter of 0.5mm and a height of 0.5mm within the range of Φ50mm. Exceeding one is regarded as unqualified.

6. Bumps—Slight bumps will occur when the product and the product collide with each other during the shot blasting of the casting or the back transportation in the factory. Without affecting the assembly performance of the casting, we are allowed to accept bumps within the range of Φ50mm with a length of 1mm, a width of 0.5mm, and a depth of 0.5mm.

Ningbo Suijin specializes in manufacturing various types of precision investment castings, and can formulate multiple sets of casting solutions that meet customer requirements according to the different needs of customers. We have a team dedicated to casting defects. We strictly follow the standards for the management and control of casting quality problems, and do our best to solve casting quality problems and prevent casting quality problems.