Sand mold casting process for heat-resisting alloy steel thin-wall pipe fitting

Abstract

The invention discloses a sand mold casting process for a heat-resisting alloy steel thin-wall pipe fitting. The heat-resisting alloy steel thin-wall pipe fitting comprises the following raw materials of, by weight, 0.35%-0.55% of C, 1%-2% of Si, 0-1.5% of Mn,0-0.04% of P, 0-0.03% of S, 27%-30% of Cr, 47%-50% of Ni, 0-0.5% of Mo, 4%-5.5% of W, and the balance Fe. According to the sand mold casting process, through improvement of the traditional process for a thin-wall M-shaped elbow casting, investment casting is changed to be sand mold casting, the casting yield and production efficiency are improved greatly, the casting size meets the requirement of a drawing, the process yield is increased to 56%, the casting pass rate is increased to 98%, and very good economic benefits are achieved.

Description

technical field [0001] The invention relates to the technical field of casting, in particular to a sand casting process for heat-resistant alloy steel thin-walled pipe fittings. Background technique [0002] M-shaped elbow is one of the commonly used pipe fittings for heating radiant tubes in continuous annealing furnaces in the metallurgical industry. Investment casting is also called lost wax casting. [0003] Although the surface quality of investment casting is better than that of sand casting, the production cost of investment casting is higher, the process yield is low, and the production cycle is long. There are many casting defects in the production of such thin-walled elbow pipe fittings by investment casting: shrinkage cavity and severe shrinkage at the hot joint on the top of the elbow, the center distance of each nozzle cannot be guaranteed, the deviation is large, the maximum deviation is 6mm, and the nozzle is elliptical , the maximum ellipticity is 8mm, whic...

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Problems solved by technology

[0003] Although the surface quality of investment casting is better than that of sand casting, the production cost of investment casting is higher, the process yield is low, and the production cycle is long

There are many casting defects in the production of such thin-walled elbow pipe fittings by investment casting: shrinkage cavity and severe shrinkage at the hot joint on the top of the elbow, the center distance of each nozzle cannot be guaranteed, the deviation is large, the maximum deviation is 6mm, and the nozzle is elliptical , the maximum ellipticity is 8mm, which does not meet the circular requirements

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