Based on the analysis of the results of the improvement, the casting process can be further optimized to ensure the maximum function of the brake caliper in the operation of the car.
（1） Improve the gating system
For the brake caliper of automobile, under the effect of the original casting process, the riser size and cross-sectional area of riser neck are too small, the fluidity and feeding effect of molten iron are not high, the shrinkage cavity and porosity are easy to occur at both ends and bottom of the casting, so it is necessary to scientifically improve the corresponding pouring system based on the actual situation of casting based on the specific analysis of defects. The riser of automobile brake caliper is a key point that can not be ignored in the improvement. The riser which is independent at both ends of the casting can be changed into a common riser, which can be set at a reasonable position of the casting to solve the problem of too small cross-sectional area of the riser neck. The sprue nest is set at the bottom of the sprue, which can effectively control the kinetic energy generated in the molten iron downflow and shorten the high-speed turbulent area of molten iron to a certain extent To ensure that the casting can be filled with molten iron smoothly during the casting process, and minimize the occurrence coefficient of shrinkage porosity at the source. In addition, in the process of improving the pouring system, we should pay attention to the filling temperature, which is 1271-1420 ℃ [3] at the completion of filling, effectively control the temperature and improve the stability of filling, so as to provide an important guarantee for the smooth solidification of castings. In order to solve the problem of shrinkage and porosity at the bottom of casting, the sand core can be rationalized and the external chill can be placed in the process of improving the gating system. On the basis of solving the problem of shrinkage and porosity of casting, the mechanical properties of automobile brake caliper can be maximized.
（2） Adjust alloy composition
Alloy composition adjustment is also an effective method to improve the casting process of automobile brake calipers. Under the effect of the original casting process, the alloy composition of the brake caliper needs to be improved. In the process of theoretical exploration and practical exploration, aiming at the performance and strength of the brake caliper, the alloy composition should be adjusted reasonably on the basis of repeated trial production. The manganese content after the furnace is 0.35%, the copper content should not be less than 0.2%, nor more than 0.25%. In the process of interaction, manganese should be maximized The ferrite in the casting is strengthened by effective solution, and the alloy cementite is formed at the same time of dynamic control of manganese content, which is presented in the form of pearlite. The proportion of pearlite in the casting matrix is reasonably increased, the yield and tensile strength of the casting are maximized in the process of plasticity reduction of the casting, and the elongation can also be effectively controlled in the specified atmosphere. At the same time, under the continuous action of manganese, the pearlite temperature in the casting matrix is effectively controlled to prevent it from exceeding the specified range, and the linear relationship between pearlite sheet distance and supercooling degree is well controlled to improve the strength of automobile brake caliper. Copper can also play a positive role in pearlite. It can maximize its function based on the adjustment of copper content, improve the matrix structure of nodular cast iron, ensure that the alloy composition is more scientific and reasonable on the basis of optimized configuration, further regulate the alloy composition on the basis of mastering the pouring process, and effectively meet the requirements of mechanical properties in the application of automobile brake calipers, Improve the overall effect of brake caliper application.
（3） Improvement effect of casting process
By using microscope and many kinds of modern information technology, we can understand comprehensively, deeply and systematically the operation effect of automobile brake caliper after the optimization and perfection of gating system and scientific adjustment of alloy composition. From the trial production results, after the improvement of the casting process, the shrinkage porosity problems at both ends and the bottom of the brake caliper of the car were effectively solved, and the pearlite content in the casting matrix increased to about 15% [4]. At the same time, the tensile strength, yield strength and elongation of automobile brake calipers have been significantly improved, and the mechanical properties and mechanical properties have been significantly improved, which can fundamentally reduce the failure factor in the application of automobile brake calipers, safely and stably operate in the harsh environment, give full play to the advantages of many aspects, and improve the overall performance of automobile brake system Comprehensive benefits of automobile operation.