Casting method for engine exhaust for petroleum drilling

Abstract

The invention discloses a casting method for an engine exhaust for petroleum drilling. The casting method comprises the following steps that during casting, high-strength low-air generation film coated sand is adopted, the air generation amount is controlled to be lower than 12 ml / g, the normal temperature extension strength is 2.2 MPa or above, the core surface is coated with alcohol based coating, and air outlet holes are punched in all exposed core heads; the cross section of a pouring gate is increased, a sprue is increased from phi 30 cm to phi 40 cm, the cross section of a cross gate isincreased from 3.2 cm<2> to 4 cm<2>, the cross section of an ingate is 4 cm<2>, the height of the sprue is increased to 50 cm, and pressing heads are heightened; and the casting temperature is improved from 1380 DEG C to 1450 DEG C, and generated gas can be conveniently overflowed out of pieces. According to the casting method, the aim of quick mold filling is achieved, relatively high pressure isbuilt in molds, gas generated by sand cores in the early period and entering iron liquid and can float out of the pieces, the above measures are effectively and stably controlled, and high finished product rate of series castings can be obtained possibly.

Description

Technical field [0001] The present invention relates to the field of casting technology, in particular to a casting method for an engine exhaust manifold for oil drilling. Background technique [0002] The existing castings have a channeled skin structure, the outer layer is a channeled water layer, the thinnest part of the sand core is 5mm, generally 12.7mm and there is almost no exhaust channel; the wall thickness of the casting is relatively large, the thin wall is 9.5mm, the thick wall is 60mm ; Therefore, no matter the exhaust of the sand core and the feeding of the casting, it is easy to cause the porosity and shrinkage of the casting. Analyze the undesirable phenomenon of the casting. The main reason is that the core is out of gas and the gas cannot be discharged in time. Relatively thick parts, or because the sand core is relatively thin, under the action of high temperature molten iron, the tip deflates and produces pores. Summary of the invention [0003] The purpose of...

AI Technical Summary

Problems solved by technology

[0002] The existing castings have a channeling skin structure, the outer layer is a water channeling layer, the thinnest part of the sand core is 5mm, generally 12.7mm and there is almost no exhaust channel; the wall thickness of the castings varies greatly, the thin wall part is 9.5mm, and the thick wall part is 60mm ; Therefore, regardless of the exhaust of the sand core and the feeding of the casting, it is easy to cause the pores and shrinkage of the casting. The analysis of the bad phenomenon of the casting is mainly due to the gas of the core, and the gas cannot be discharged in time, and it remains on the top of the casting in the late stage of solidification. Relatively thick and large parts, or the sand core is relatively thin at this place, and under the action of high temperature molten iron, gas holes are generated at the tip of the tip