Method for producing large six-cylinder cylinder block through sand-coated iron mold casting

Abstract

The invention discloses a method for producing a large six-cylinder cylinder block through sand-coated iron mold casting. An inner cavity of an iron mold is manufactured according to the profile of the cylinder block, the thickness of a sand coating layer ranges from 5 mm to 20 mm, and semi-closed semi-open sprues are adopted; core heads on the periphery of an upper half mold, a boss on the highest position of the upper half mold and a core head of an accessory sand core on the water jacket surface are correspondingly provided with pore needles, and an overflow groove is formed in the end of the cylinder top face; a technological exhaust groove is formed in the cylinder top face; a heating device is arranged between an upper mold bottom plate and a lower mold bottom plate, and electric heating tubes are arranged in a mold sample; exhaust plugs are mounted on the periphery of the mold sample; sand jet is conducted after the mold and the iron mold temperature reaches the requirement; and then core mounting, box combination, pouring and box opening are conducted. By means of the method, the yield is increased by over 72% from original 78% of sand mold casting, the defects of blowholes and structure loosening are overcome, the problem of leakage of the large six-cylinder cylinder block is solved, the whole mechanical performance is improved, and sand treatment equipment, sites and the sand consumption are reduced; and the severe casting environment is improved. The method is simple in technological process and easy to control, and the production cost is 25-40% lower than that of sand mold casting.

Description

Technical field [0001] The invention belongs to the field of engine cylinder block casting, in particular to a production method for casting a large six-cylinder cylinder block with iron mold sand coating. Background technique [0002] Iron mold sand-coated casting is a casting process in which a thin layer of molding sand (also called coated sand) is covered around the inner cavity of a metal mold (also called iron mold). It is a combination of metal mold casting and shell mold casting. The obtained castings have the advantages of high dimensional accuracy, good mechanical properties, dense material structure, labor saving, materials and equipment, and low production costs. [0003] In China, the application research of iron mold sand-coated casting process is used in the production of crankshaft or ductile iron. In recent years, nearly one hundred enterprises across the country have also applied the iron mold sand-coated casting process. In addition to ductile iron crankshafts,...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a production method for casting large-scale six-cylinder cylinder blocks covered with iron molds to solve the common problems of gray iron or vermicular iron large-scale cylinder blocks with six cylinders and above, loose tissue, air (shrinkage) holes, and surface quality. Poor, the overall mechanical properties can not be guaranteed and the problem of high casting cost