Why are the products produced by steel casting manufacturers rough in appearance
The products produced by steel casting manufacturers are diversified in mechanical use, such as complex shape, structure and quality requirements, which have an impact on the casting itself. In the process of production, most of them adopt the pouring method, and the defects such as cracking, sand sticking, sand washing and so on that occur during the pouring process are relatively common, which will lead to the poor appearance quality of the castings, which will increase the workload of finishing, and will have a very obvious difference compared with the appearance of products produced by other large steel casting plants.
During the processing of steel castings, attention should be paid not only to the quality problems, but also to the appearance of the products. The following are the reasons for the deterioration of the appearance quality of the castings:
1. The grain size of molding sand and sand core is coarse, and the compactness is low;
2. The choice of coating is poor, and the coating thickness is uneven, and the coating will peel off;
3. The pouring temperature is also too high, and the hydraulic pressure is relatively high;
4. The cupping degree of upper box or gate is too high, and the hydrostatic pressure is too high;
5. Molding sand and core sand contain more adherents, low refractoriness and poor thermal conductivity;
6. Molding sand and core sand contain more recycled sand, and the sintering temperature is low;
7. When the sand falls out late, solid hot sand will be formed, especially some thick castings and high melting point alloy castings;
8. Metal liquid has good fluidity, but low surface tension;
9. The gating system and riser are improperly treated, resulting in local overheating.
The reasons for rough appearance of castings summarized above can be prevented from these points when producing products!