Study On Casting Process Of Copper Alloy Cooler Cover

Cooler cover, which is an important part of a cooler, requires its components to have a great corrosion-resistant ability and good sealing, especially corrosion resistance for the flowing water, steam and inorganic acid and airtight performance, watertight performance under high pressure.Copper has good seawater corrosion resistance, which makes it used widely in shipbuilding and shipping industry. Mn, which is an addition, can improve the corrosionresistant properties in seawater, chloride and superheated steam. Therefore, this cooler cover cast is made of manganese brass, the model of which is ZCuZn38Mn2Pb2. Compared with ordinary brass, the hardness, strength and wear resistance of Mn brass are better, especially strong resistance to corrosive atmosphere and seawater or any other corrosive liquid.In the process of producing copper alloy cooler cover, the main problem resulting in scrap cast was that the leakage happened in the hydraulic test, leading to a fact that products could not meet the requirement of the performance test, and the yield was only 20%. The direct results were the increasing cost of production and delaying the time limited for a project.In order to improve the rate of qualified products, the mock software, ProCAST, was applied to do the numerical simulation of solidification process and casting process of the original process project. The results showed that some concentrated shrinkage cavity formed in cast hot section, because of the unreasonable gating system design and the uneven temperature gradient during solidification process and the not strong enough feeding effect. The concentrated shrinkage cavity became leakage passages in the hydraulic test, the result of which was that the cast could not meet the technical requirements. In order to explore the reasons that so many concentrated shrinkage cavity appeared in hot spots, the macro-structure and micro-structure of cooler cover cast were observed by SEM, and the chemical composition were analyzed as well. The results showed the reason leading to shrinkage cavity was that oxide inclusion generated by mental liquid and mental liquid could not feed completely.Based on the mechanism of the original process resulting in defects, two improved processes were designed and the original melting process was also optimized. The numericalsimulation of two casting processes was done with the help of ProCAST to verify the rationality of two casting processes and ensure the new technology scheme of manufacturing cooler cover to be the second one of top pouring system.The new process and the optimized melting process were adopted. In addition, the microstructure observation and performance test were also achieved. The results showed that the test results were consistent with the simulation results. Compared with the original process, cast produced in the new process had even and compact texture. Hardness, friction, wear properties and tensile properties all improved, and the problem of shrinkage defect was almost avoided.Yield was up to 85%.