Casting core making material and core making method

Abstract

The invention discloses a casting core making material. The casting core making material comprises, by weight percentage, 55%-65% of steel shots, 15%-25% of carbon granules and the balance silica sand. The particle size of each steel shot ranges from 0.5 mm to 1.5 mm, and the granule size of each carbon granule is smaller than 1.0 mm. The casting core making material can be used instead of conventional formed direct or indirect chill iron, the casting defects such as shrinkage cavities and shrinkage porosity of castings are effectively overcome, the molding difficulty is reduced, the cleaning and polishing labor time of the castings is shortened, the production efficiency of the castings is obviously improved, and the product quality of the castings is guaranteed. The casting core making material is particularly suitable for the castings with the high quality requirements and the regions where the chill iron is difficult to place or clean, such as pressure vessel or oil cylinder parts with guide pillar holes and the castings with long and thin holes formed in the side walls, the number of the casting defects is effectively reduced, or the casting defects are effectively overcome, and the product percent of pass is improved. The compressive strength of a sand core which is obtained according to a core making method is 2.9 MPa or above, and the pouring requirements of the castings are completely met.

Description

technical field [0001] The invention relates to the technical field of casting core making materials, in particular to a casting core making material and a core making method. Background technique [0002] During the production process of castings, shrinkage porosity and shrinkage cavities of castings are often encountered, especially some pressure vessels or oil cylinder parts near the middle hole and side walls are prone to shrinkage porosity and shrinkage cavity defects. Especially in the process of casting oil cylinder parts, in order to ensure the stability of the casting quality, the forming cold iron is chosen to be placed in the core making process, which makes cleaning and grinding difficult, and greatly increases the difficulty of modeling. [0003] The traditional casting method uses forming direct chill iron, which has many influencing factors, is difficult to control, and cannot completely eliminate defects. For example, when the outer contour of the casting is...

AI Technical Summary

Problems solved by technology

Especially in the process of casting oil cylinder parts, in order to ensure the stability of the casting quality, the forming chill iron is chosen to be placed in the core making process, which makes it difficult to clean and polish, and greatly increases the difficulty of modeling

[0003] The traditional casting method uses forming direct chill iron, there are many influencing factors, it is not easy to control, and the defects cannot be completely eliminated

For example, when the outer contour of the casting is arc surface or curved surface, it is not easy to detect and find defects by ultrasonic (UT) flaw detection. The defects are exposed during final processing, making the parts unusable and scrapped, resulting in increased costs and long production cycles, which will seriously affect Agreement delivery date

[0004] In addition, the following problems still exist in the use of forming cold iron: 1. It is necessary to make cold iron molds, which increases the production man-hours; 2. The cost of the shape, mold closing, pouring, unpacking, and polishing of the cold iron itself is relatively high; 3. Preservation and molding Chilling iron requires a lot of manpower and space; 4. There must be gaps between the forming chilling irons, which may cause the sand to be not tightly packed and the strength of the sand mold to be low, resulting in defects in the casting; 5. Difficulty placing the chilling iron during molding 6. Due to grinding and deformation of the forming cold iron, the fit with the mold is not tight, resulting in excess or lack of material in the casting

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