ZL115Flanged Valve Heat Treatment Improvement

With the development of industrial technology, aluminum has already become the widest non-ferrousmetal material in industrial application, which largely used in aviation, spaceflight, automobile, machinebuilding, shipping etc. Especially, ZL115which has strongly corrosion resistance has largely used inshipping building. However, the lower intensity of mechanical properties of ZL115restricts its furtherapplication. Heat treatment which is the simplest and most effective way in raising aluminum’s mechanicalproperties has widely used aluminum casting structures. Heat treatment can greatly raise mechanicalproperties of aluminum structures, put up productivity and cut the cost.The effect of ZL115heat treatment on this aluminum alloy’s mechanical properties is studied in thiswork. By use of optical microscope and the SEM, with the method of energy spectrum analysis and so on,the effect of the heat treatment parameters on the microstructure features is covered. Besides, the size, thenumber and the distribution of the silicon penetrated in the interface are studied. In addition, the tensilestrength, the extension rate, and the Brinell hardness are measured. The results are as follow:In the condition of the same aging treatment, promotively-solutionizing can prevent the microstructurefrom over-heating. And at the same time, the over-saturation after quenching is increased and themechanical properties increase at first and then decrease as the time of the first round solution treatment islengthened. While the mechanical properties increase at first and then decrease as the time of the solutiontreatment is lengthened.In the same condition of solution treatment and pre-aging treatment, when the terminal aging treatmenttemperature is220℃, the mechanical properties get higher and higher as the time of the terminal agingtreatment is lengthened. With the same time of the terminal aging treatment, the mechanical properties gethigher and higher as the temperature of the terminal aging treatment is increased.The best choice of the heat treatment is determined:520±3℃×6h+540±3℃×7h, water quenched at thetemperature of60℃,120±3℃×7h+220±3℃×5h, cooled in the open air. The samples treated with thischoice have higher mechanical properties than those of the Standard GB/T1173-1995. And their tensilestrength exceed to327.2Mpa.