Heat resisting low expansion silumin and preparation thereof

Abstract

The invention belongs to the field of non-ferrous materials and preparation and formation thereof, and relates to heat-resisting low-expansion high-silicon cast aluminum alloy. The alloy comprises the following compositions in percentage by mass: 18 to 25 percent of silicon, 1.0 to 2.5 percent of copper, 0.2 to 0.8 percent of magnesium, 0.5 to 2.5 percent of nickel, 0.3 to 0.6 percent of manganese, 0.3 to 1.0 percent of misch metal RE (the content of cerium is more than 40 percent), 0.006 to 0.04 percent of phosphorus, and the balance of aluminum. The production method comprises: firstly, melting raw materials of copper, nickel, silicon and aluminum into an aluminum silicon alloy fused mass; secondly, re-superheating the aluminum silicon alloy fused mass to the temperature of between 850 and 870 DEG C, adding manganese raw materials, and obtaining a mixed fused mass after uniform melting; thirdly, adjusting the temperature of the mixed fused mass to between 780 and 800 DEG C and adding the magnesium into the mixed fused mass; fourthly, adding rare earth raw materials into the mixed fused mass, maintaining at the temperature for 10 to 15 minutes, and raising the temperature to between 820 and 840 DEG C; fifthly, performing refining; and sixthly, raising the temperature of the refined mixed fused mass to between 830 and 850 DEG C, adding phosphorus raw materials into the mixed fused mass for modification, maintaining at the temperature for 15 to 20 minutes after modification, and performing casting, wherein the casting temperature is between 790 and 830 DEG C. Castings can well meet the performance requirements of peripheral materials of automobile engines after T6 heat treatment.

Description

technical field

[0001] The invention belongs to the field of non-ferrous metal materials and their preparation and molding, and relates to a cast aluminum-silicon alloy material used at high temperature, that is, a heat-resistant low-expansion high-silicon cast aluminum alloy and a preparation method thereof. Background technique

[0002] At present, the design of automobile engines is developing in the direction of high speed and low energy consumption. The engine speed and temperature increase, so the requirements for engine piston materials and cylinder materials are correspondingly increased, mainly focusing on heat resistance, wear resistance, and corrosion resistance. Good performance, small thermal expansion, light weight, etc., so it is particularly important to choose suitable materials. Many cars use aluminum alloy materials for engine pistons, radiators, oil pans, cylinder blocks and cylinder heads, crankcases, filters and other components. There are roughly four...

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