The pouring process is a key link in the entire production process of large-scale engineered castings. If this link is not handled properly, it will be difficult to cast qualified large-scale castings. Therefore, in the production of this large-scale casting, the pouring process should be carried out in strict accordance with the requirements and various operations.
Ⅰ. Requirements for the production of engineered castings
To obtain qualified engineered castings. It is critical to strictly control the pouring temperature, pouring speed, and strictly abide by the pouring operation rules.
1. As far as the pouring temperature of large steel castings is concerned, the pouring temperature has a great influence on the quality of the castings. The reasonable pouring temperature range should be determined according to the type of alloy, the structure of the castings and the characteristics of the mold. Select a reasonable pouring temperature according to the type of carbon steel, generally the pouring temperature is between 1540-1580 ℃ (the temperature of the molten steel in the ladle).
2. As far as the pouring speed of engineered castings is concerned, under the condition that the gas in the cavity can be discharged smoothly, a higher pouring speed can be used for castings that require simultaneous solidification, and a higher pouring speed can be used as far as possible for castings that require sequential solidification. Low pouring speed.
3. As far as the pouring operation requirements of big castings are concerned, it is generally necessary to comply with the following points:
a. When pouring large and medium-sized castings, the molten steel should be placed in the ladle for 1-2 minutes to be sedated before pouring.
b. After the casting is solidified, remove the weight and box clip in time to reduce the shrinkage resistance of the casting and avoid crack defects in the casting.
In the early stage of pouring of big castings, the manufacturer should make sufficient preparations to ensure that the subsequent pouring operations can be carried out smoothly, and sufficient preparations before pouring can ensure the normal progress of the subsequent work.
Ⅱ. Density properties of engineered castings
When engineered castings are cast, they generally need to undergo many heat treatment measures to improve the performance of large-scale castings in all aspects. Among them, the process of water-cooled heat treatment for steel castings is actually a way to improve The density method makes the structure of big castings more compact. However, many people may still not understand, what properties are related to the density of big castings?
1. The higher the density of big castings, the less likely defects such as bubbles and cracks will appear, thus reducing the scrap rate;
2. Large-scale steel castings with higher density are more suitable for use as precision large-scale steel castings, and the steel structure of large-scale steel castings will be more accurate;
3. The influence of the density of large steel castings on toughness is also very large. The higher the density of big castings, the higher the toughness will become.
Therefore, it is very important to increase the density of big castings, which can greatly improve the quality of engineered castings.