In modern casting technology, with the continuous development of process technology, the quality of castings is improving day by day, which can meet the application needs of different fields. Currently, furan sand casting technology has been widely used due to its advantages such as good quality and scrap rate. However, in furan sand castings, defects in furan resin sand are an important factor affecting the quality of the castings. Insufficient strength and poor permeability of furan resin sand can directly affect the quality of castings. Therefore, the optimization and improvement of furan sand casting technology is crucial for improving the quality of furan sand castings. This article is based on the analysis of furan sand casting technology, and provides the following specific explanations on how to achieve the transformation and development of furan sand casting technology.
1. Strength control:
In the process of furan resin sand casting, the strength control of resin sand is particularly important, which directly affects the effectiveness of casting technology and process. The strength of resin sand is directly related to the amount of resin added and the strength of silica sand. Therefore, from the perspective of resin strength, the transformation of furan resin sand casting technology mainly involves two aspects:
1.1 Scientific control of resin content
Research has found that if the amount of resin added is too small, it can lead to low strength of furan resin sand castings and easily cause casting problems such as sand flushing; If the amount of resin added is too high, it will form a large amount of gas due to excessive strength, resulting in porosity defects. As shown in Figure 1, the strength changes under different resin addition amounts are shown. It can be seen from this that as the amount of resin added increases, its strength also increases. However, after the addition amount was 1.5%, the intensity enhancement decreased. This indicates that as the amount of resin added increases, after adding a certain amount, excessive resin will increase the thickness of the adhesive film on the surface of the sand particles, which will lead to a decrease in the relevant strength. Therefore, in the technical control and transformation of furan and castings, attention should be paid to the addition of resin content.
(1) The amount of resin added should be controlled between 0.8% and 1.5%. From Figure 1, it can be seen that after adding 1.5% resin, the increase in strength significantly slows down. This indicates that although an increase in resin content will gradually enhance its strength, the increase in strength will also lead to a decrease in adhesion, which will actually affect the quality of furan resin sand castings. Therefore, in the technical transformation of furan sand castings, the key is to strengthen the control of resin addition, which can not only ensure strength but also reduce the cost of furan sand castings.
(2) The amount of resin added should pay attention to the performance requirements of castings. Due to the different performance requirements of furan sand castings, there are differences in the control of resin addition amount. Therefore, it is necessary to scientifically control the amount of resin added based on actual demand, taking into account both strength and cost. In general, when the resin content is less than 0.8%, the strength of furan resin sand castings is less than 3 Mpa. At this strength, the performance of furan resin sand castings is weak, and it is emphasized to ensure effective technical transformation in controlling the performance of furan resin sand castings.
1.2 Reasonable selection of silica sand particle size
In the process of furan resin sand castings, the particle size of silica sand is also an important factor affecting the quality of furan resin sand castings. In essence, the particle size of silica sand mainly involves the particle size and distribution of silica sand. As shown in Figure 2, the strength variation under different silica sand particle sizes. From Figure 2, it can be seen that the silica sand with a strength of 40/70 mesh has the highest strength, and the strength is the best in the 3-sieve state. Therefore, in order to better improve the strength performance of furan resin sand castings, a 3-sieve 40/70 mesh silica sand is generally selected. This not only ensures the strength of furan resin sand castings, but also reduces process costs.
2. Scientific control of process parameters:
In the process technology of furan resin sand castings, the scientific control of relevant process parameters is related to the quality of furan resin sand castings. Especially the effective control of curing strength, curing time, etc., can better improve the technical effect of the process. This is an important part of the technical transformation of furan resin sand castings and a key focus of controlling process parameters. Therefore, specifically, the main focus is on scientifically controlling the following process parameters.
2.1 Curing strength control to solve the problem of porosity in furan resin sand castings
In furan resin sand castings, the curing strength is mainly divided into initial strength and final strength. Among them, the initial strength is the tensile strength after 1 hour of curing. The quality control of furan resin sand castings is particularly important, as it is an important foundation for the formation of final strength. The final strength is the tensile strength after 24 hours of curing, which needs to be controlled at around 0.9 Mpa. For furan resin sand castings, the higher the curing strength, the better. The control of final strength needs to be based on actual needs, and the increase in curing strength requires the addition of furan resin sand. This not only increases the corresponding cost of furan resin sand castings, but also easily leads to porosity in furan resin sand castings under excessive furan resin, which can actually affect the curing strength. Therefore, reasonable control of curing strength can help solve the problem of porosity in furan resin sand castings and ensure the process quality of furan resin sand castings.
2.2 Curing time control to improve the quality of furan resin sand casting models
In general, there are strict requirements for the curing time of furan resin sand castings, which is an important basis for ensuring the quality of furan resin sand castings. However, from a practical perspective, in the process of some furan resin sand castings, due to unreasonable control of curing time, the self hardening strength is insufficient, which has a significant impact on the quality of the castings. Therefore, in the process of furan resin sand castings, firstly, it is necessary to scientifically control the curing time. Generally, within 24 hours, the resin will harden on its own and reach its maximum strength within 24 hours. This is particularly important for ensuring the curing strength; Secondly, during the solidification process, it is necessary to effectively control the quality of the furan resin sand casting model within a controlled time, especially during the pouring and molding process, with strict control over the intervals between them, which should be completed within 24 hours, which is related to the overall quality of the furan resin sand casting.
2.3 Control the amount of sand consumed and scientifically reduce the sand iron ratio
The strength of furan resin sand castings is related to the amount of sand consumed. The more sand is consumed, the lower the strength of furan resin sand castings. On the contrary, the less sand consumption, the higher the strength of furan resin sand castings. That is to say, in the quality control of furan resin sand castings, the improvement of its related process technology is particularly important. Firstly, in response to the performance requirements of furan resin sand castings, scientifically and reasonably controlling the sand iron ratio can effectively improve the strength of furan resin sand castings while reducing the use of curing agents, which plays an important role in avoiding porosity defects in furan resin sand castings; Secondly, at a low sand to iron ratio, castings may experience fire runaway during pouring, which has a certain impact on the quality and safety of furan resin sand castings; Once again, in the process of controlling the amount of sand consumed, the sand iron ratio should be appropriately reduced within a scientifically reasonable control range. Research suggests that as the sand iron ratio increases, the LOI value also increases, which can easily lead to the occurrence of porosity defects. Therefore, in the transformation of furan resin sand casting technology, scientifically and reasonably reducing the sand iron ratio can help improve the control of sand consumption.
3. Breathability control:
In the technical control of furan resin sand castings, air permeability control is particularly important, which is an important factor affecting the performance of the castings. Therefore, in the improvement of furan resin sand casting technology, it is necessary to strengthen the scientific control of compactness, and in terms of operability, improve the technical characteristics of furan resin sand castings to meet the quality control requirements of furan resin sand castings. From experimental research, it can be seen that scientific control of relevant process parameters is an important part of the technical process audit of furan resin sand castings, which is related to the quality of furan resin sand casting transformation.
3.1 Scientific control of compactness to improve the strength of furan resin sand castings
Due to the fact that permeability is an important factor affecting the strength of furan resin sand castings, effective control of their compactness is necessary to better achieve technical transformation. In the technical control of furan resin sand castings, scientific control of compactness can achieve strength improvement by reducing the gap between resin sand particles, if conditions permit. Therefore, in the technical transformation of furan resin sand castings, it is necessary to effectively control the technical process characteristics through the relationship between the number of compactions and strength, and avoid defects such as porosity in the processing of furan resin sand castings while improving their strength.
3.2 Improve operability and reduce parameter impact
The improvement of operability in the technical control of furan resin sand castings is directly related to the quality control of furan resin sand castings.
(1) Usable time. The usable time is an important technical parameter for controlling the quality of furan resin sand castings. According to research data, effective control of available time is directly related to the growth of compressive strength of resin sand. In general, in the control of factors such as sand temperature and environmental temperature, it is necessary to strengthen the reasonable proportion of curing agent addition, effectively shorten the usable time, and ensure the process quality of furan resin sand castings.
(2) Resin sand molding time. The smaller the ratio of mold start time to usable time, the better. This not only allows sufficient time to complete the quicksand operation, but also improves production efficiency, and can improve the comprehensive economic benefits of furan resin sand castings.
4. Conclusion
In summary, the control of relevant process technologies is an important foundation for ensuring the quality of furan resin sand castings in the application and construction of furan resin sand casting technology. In this study, the technology and process of furan resin sand castings involve many aspects. The key to achieving effective transformation of the technology and process is to focus on the performance requirements of castings, and comprehensively improve the technical performance of furan resin sand castings through measures such as strength control, permeability control, and process parameter control. This is an inherent requirement for the development of furan resin sand casting technology and an important starting point for process technology transformation. In the current era of continuous development of casting technology, the upgrading and transformation of furan resin sand casting technology needs to focus on the characteristics of furan resin sand castings and ensure the quality of furan resin sand castings through high-quality control.