According to the comprehensive evaluation results of typical sand casting processes, for the static pressure casting process and V method casting process, the smelting process has the greatest impact on resources and environmental loads of the four processes, followed by the molding process, followed by the cleaning process and pouring process. The smelting process has the greatest impact and is obviously different from other processes. The green transformation of sand casting process should focus on this process, mainly from the aspects of reducing auxiliary material consumption, adopting energy-saving process, instant collection of waste and harmless treatment. The comprehensive evaluation results of the modeling process and the cleaning process are similar, but the human health indicators of the cleaning process are high, and the particulate matter and toxic gas emissions in this process are high, which has a great impact on the operators. Therefore, the waste gas collection and treatment in this process should be improved, and the workers’ health protection measures should be strengthened. The pouring process has the least impact, especially in terms of resource indicators and environmental indicators, which are almost negligible. The main environmental load is also the impact of exhaust gas emitted during the process on human health. For this process, the automation level should be improved to improve the efficiency of exhaust gas collection and treatment.
By comparing and analyzing the two sand casting processes, the comprehensive evaluation value of static pressure casting process is 23% higher than that of V method casting process. Among them, the difference between the comprehensive evaluation results of the two processes in the smelting process is 22%, which is the main source of the difference between the two process data results. In the smelting process, the V method casting process takes pig iron as the main raw material, while the static pressure casting process uses more steel, and the static pressure casting process also invests more in auxiliary materials. In terms of process parameters, the smelting temperature of the static pressure casting process is 50~70 ℃ higher than that of the V method casting process, and the heating above 1000 ℃ is higher for power consumption, The above three differences result in higher resource and environmental load of static pressure casting process in smelting process.
From the perspective of resource consumption, environmental load and human health impact, the results of V method casting process are lower than those of static pressure casting process. This is related to three factors. First, the V-method casting process uses vacuum negative pressure molding, which reduces the use of adhesives compared with the static pressure casting process, and effectively reduces the impact of the molding process on resources and environment. Second, the V method casting process is mainly used to cast large castings, and the static pressure casting process is used to produce small and medium-sized castings. This paper uses the average consumption of one ton of finished castings to calculate. Similarly, to produce one ton of finished products, the static pressure casting process requires more processes, which results in greater impact of the static pressure casting process on the environmental load. Third, the products of the static pressure casting process studied in this paper are mainly axle housing and wheel housing, and the products of the V method casting process are mainly counterweight large pieces. The material requirements of the former are higher than those of the latter, which is reflected in the higher technical requirements of smelting and cleaning in the process, and also affects the impact of the process on resources and environmental loads to a certain extent.
To sum up, the main process affected by resource and environmental load in the production process of two typical sand casting processes is smelting process. In the process of green improvement, we should start from this process to reduce the consumption of raw and auxiliary materials and carry out energy-saving design; The waste gas emission in the molding and cleaning process is relatively high, which has a great impact on the health of workers. In the process improvement, attention should be paid to the collection and treatment of the exhaust gas. In the whole production process, the V method casting process has less impact on resources and environmental load than the static pressure casting process.