Gray cast iron automobile engine main bearing cover iron mold sand-coating casting method

Abstract

The invention relates to a gray cast iron automobile engine main bearing cover iron mold sand-coating casting method. The method utilizes the characteristics of precoated sand shell mold and metal mold casting of iron mold sand-coating casting, and sets the thickness of a sand-coating layer to be 5-10mm and the thickness of an iron mold to be 20-40mm according to the difference of a casting structure and a mold cavity layout, and the cooling speed of the poured casting is controlled by adopting different sand coating layer thicknesses and iron mold thicknesses in an iron mold cavity; and the alloying elements Mn, Cu and Cr are adopted, the content of Mn is 0.50%-1.10%, the content of Cr is less than or equal to 0.40%, and the content of Cu is 0.40%-1.00%, so that the as-cast high-strengthgray cast iron in an A-type graphite form can be stably obtained at the same time. The cooling speed of the casting is controlled through different sand coating layer thicknesses and iron mold thicknesses of the casting in the cavity, furnace burden is reasonably proportioned, the chemical components of the iron liquid, the in-ladle inoculation amount, the stream inoculation amount, the box opening time and the box opening temperature are controlled to stably reach the as-cast high-gray cast iron engine main bearing cover, and therefore the mechanical property of the casting is improved; and the matrix structure is refined, the A-type graphite in the graphite form is increased and uniform, and the stability and reliability of the gray cast iron material are guaranteed.

Description

Technical field[0001]The present invention belongs to the field of ferrous sand-shaped casting, and is specifically involved in a gray-cast iron automotive engine main bearing ferrule iron sand cover casting method.Background technique[0002]In the 1960s, the iron-shaped sand casting technology began to cast production in Germany, former Soviet Union and other countries, mainly used to produce balls, brake hubs, brake discs, cylinder jackets, bomb shells, tank crawles, and motor bases. The application of iron-shaped sand casting is a special casting method that has developed in the early 1970s.[0003]At present, the iron-type coated casting technology has been successfully applied to the production of the spindle cover of the ductile iron gasoline engine, which involves the ball ink cast iron card: QT450-10, QT500-7, QT600-3, etc., which mainly use alloying, composite gestation As well as the casting cooling time and other measures to cast the metachasic tissue and mechanical properti...

AI Technical Summary

Problems solved by technology

However, the production of high-strength gray cast iron main bearing caps for automobile engines has not yet been applied to iron mold sand-covered casting. It can be achieved stably, especially the shape of graphite cannot meet the requirements. Generally, A-type graphite in the graphite shape of gray cast iron main bearing cap

Therefore, the production of high-strength gray cast iron main bearing caps generally adopts the traditional sand casting method at home and abroad, and its disadvantages are low production efficiency, difficulty in ensuring dimensional accuracy, high energy consumption, and high scrap rate

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