Research On Casting Aluminum Alloy Of Marine Propeller

Lightweight materials has been paid more and more extensive attention by the material researchers along with the growing energy shortages and environmental pollution problems. Ship’s own lightweight is the most effective and direct way for energy conservation and emissions reduction. Marine propeller is a relatively independent power equipment part on ship and is mainly produeed by casting. Its manufacturing process and the change of the technical scheme has the flexibility. thus, realizing the light ship can first of all, from the perspective of the lightweight propeller.Al-Cu alloy has many advantages such as good mechanical properties at room and high temperature, good machinability and heat resistant performance and it’s often used in large structure and mechanical components by casting. But as a result of wide range of crystallization temperature, gruel way solidification, bad casting performance like li quidity. hot resistance and poor airtight performance, Al-Cu alloy is prone to generate some casting defects such as shrinkage porosity, slag inclusion, hot cracking, segregat ion and pinhole when feeding during the poor crystallization. Therefore, trying to impr ove the performance of Al-Cu alloy and expand its application field is of great significan ce.The paper studied the influence on the alloy’s microstructure and mechanical properties through the rotary, impeller degrassing process and rare earth element Gd added based on typical ZL205A alloy as object which belongs to Al-Cu alloy. At the same time, tried to improve the mechanical properties of alloy through solid solution and aging heat treatment process. The results show that:Rotary impeller to degass ZL205A alloy can obviously reduce the casting defects such as porosity and slag, and also can improve the mechanical properties of the tensile strength and elongation of the alloy.The adding of rare earth element Gd to ZL205A alloy can refine as-cast microstructure of ZL205A alloy. When the amount of Gd addition is0.03wt%, the grain of the alloy gets a degree of refinement; when the addition amount is0.06wt%, the refining effect is best; but if adding excessive Gd, the refinement effect deteriorates, and the massive big block compound increased significantly in the microstructures.Rare earth element Gd can significantly increase the ZL205A alloy’s mechanical properties under as-cast and after T6heat treatment, but with the increase of Gd addition, all show a trend of decrease after the first increase. When the amount of Gd addition is0.06wl%, the comprehensive mechanical performance of the alloy is optimal. The tensile strength reaches192MPa. the elongation is11.1%as as-cast; and the tensile strength is42I. I MPa. the elongation is10.2%after T6heat treatment. Trace rare earth Gd have the effect of purification ZL205A. and also can significantly increase the liquidity of alloy. The length of the screw sample increased by8.7%under the pouring temperature of690℃with0.06wt%Gd added; and which increased by14%under700℃.