CN104550708A - Process for casting thick and large nodular cast iron valve plate - Google Patents

Abstract

The invention discloses a process for casting a thick and large nodular cast iron valve plate. The process comprises the steps of manufacturing a sample, modeling, making a core, baking, assembling molds, melting, casting, shaking out sands and cleaning. According to the method, massive direct chiller and external chiller are used on upper and lower surfaces of a casting for chilling, proper placement positions and thicknesses are selected, shrinkage cavity and shrinkage porosity of the casting can be effectively prevented, and the graphite balling state is excellent by means of quick chilling; a feeding head does not needed to be arranged, the casting is simple to clean, and the amount of molten iron is reduced by 5 percent, so that the production cost can be reduced; a semi-closed casting system is adopted, and the ingate is uniformly distributed on the periphery of the casting mold, so that the casting mold is lightly eroded, and the residue retaining effect is good; and under the action of chiller chilling, a thick large nodular cast iron part molten by a cupola furnace has excellent surface molding, does not contain residues or sands and can be used for meeting the production requirement, and the process yield is increased by 5.9 percent.

Description

The casting technique of thick large nodular cast iron valve plate

 

Technical field

The invention belongs to casting technology field, be specifically related to a kind of casting technique of thick large nodular cast iron valve plate.

 

Background technology

The casting technique of nodular cast iron valve plate roughly comprises manufacture apperance, moulding, makes the processes such as core, oven dry, mould assembly, melting, cast, in the pouring technology of current cast iron valve, the casting finished products made easily produces the phenomenon that foundry goods produces shrinkage cavity and porosity, not only casting process is more, affect production capacity, the precision of foundry goods cannot effectively be ensured simultaneously, and percent defective is higher.

 

Summary of the invention

In order to overcome the above-mentioned technical problem that prior art field exists, the object of the invention is to, provide a kind of casting technique of thick large nodular cast iron valve plate, can directly cast out cast iron valve plate foundry goods, and packing is high, processing technology thereof is simple.

The casting technique of thick large nodular cast iron valve plate provided by the invention, comprises the following steps:

(1) apperance is manufactured: with the wooden modeling sample of Korean pine;

(2) moulding, make core: apperance is placed in sandbox, running gate system is set, in sandbox, fill out resin sand by bottom running and carry out making casting mold, and utilize resin sand to make core; Described sandbox is two unpacking designs, comprise cope and drag box, cope is provided with the several piece of interlaced arrangement every sand cooling iron, drag box is provided with the bright chill of several piece of interlaced arrangement, be 1: 1 every the thickness of sand cooling iron and bright chill and casting thickness ratio, the spacing every between sand cooling iron is that 0.5-1 is doubly to the length every sand cooling iron; Spacing between bright chill is that 0.5-1 is doubly to the length of bright chill; Described running gate system is included in the symmetrically arranged cross gate in left and right on foundry goods, ingate and sprue, and cross gate and ingate, sprue are all arranged in cope, and sprue is perpendicular to face, cross gate place and be communicated with cross gate; Cross gate is curved, and the ingate described in several is uniformly distributed between foundry goods and cross gate, and is communicated with cross gate, foundry goods; Cast gate area ratio is S sprue: S ingate: S cross gate=1: 1.2-1.5: 0.8-1;

(3) oven dry, mould assembly: the removing surface of casting mold is clean, brushes twice with zirconium powder coating, guarantees the smooth surface that the bright chill in drag box is brushed; Dry casting mold and core, lower core, carries out mould assembly, improves bright chill and the surface temperature every sand cooling iron after mould assembly with warm-air drier baking;

(4) melting: use cupola melting molten iron;

(5) cast and peeling.

The casting technique of thick large nodular cast iron valve plate provided by the invention, its beneficial effect is, overcomes operation in prior art process technology more, the problem that workload is large, improves production efficiency; Avoid and produce because casting finished products easily produces foundry goods the mass defect that the phenomenon of shrinkage cavity and porosity causes, utilization rate of raw materials is high, reduces production cost; The finished product cast size cast out is accurate, without the need to machining, effectively ensure that casting quality.

 

Detailed description of the invention

Below in conjunction with an embodiment, the casting technique of thick large nodular cast iron valve plate provided by the invention is described in detail.

Embodiment

The casting technique of the thick large nodular cast iron valve plate of the present embodiment, comprises the following steps:

(1) apperance is manufactured: with the wooden modeling sample of Korean pine;

(2) moulding, make core: apperance is placed in sandbox, running gate system is set, in sandbox, fill out resin sand by bottom running and carry out making casting mold, and utilize resin sand to make core; Described sandbox is two unpacking designs, comprise cope and drag box, cope is provided with the several piece of interlaced arrangement every sand cooling iron, drag box is provided with the bright chill of several piece of interlaced arrangement, be 1: 1 every the thickness of sand cooling iron and bright chill and casting thickness ratio, the spacing every between sand cooling iron be 0.7 times to the length every sand cooling iron; Spacing between bright chill be 0.6 times to the length of bright chill; Described running gate system is included in the symmetrically arranged cross gate in left and right on foundry goods, ingate and sprue, and cross gate and ingate, sprue are all arranged in cope, and sprue is perpendicular to face, cross gate place and be communicated with cross gate; Cross gate is curved, and the ingate described in several is uniformly distributed between foundry goods and cross gate, and is communicated with cross gate, foundry goods; Cast gate area ratio is S sprue: S ingate: S cross gate=1: 1.3: 0.85;

(3) oven dry, mould assembly: the removing surface of casting mold is clean, brushes twice with zirconium powder coating, guarantees the smooth surface that the bright chill in drag box is brushed; Dry casting mold and core, lower core, carries out mould assembly, improves bright chill and the surface temperature every sand cooling iron after mould assembly with warm-air drier baking;

(4) melting: use cupola melting molten iron;

(5) cast and peeling.

Claims (1)

1. a casting technique for thick large nodular cast iron valve plate, is characterized in that: comprise the following steps:

(1) apperance is manufactured: with the wooden modeling sample of Korean pine;

(2) moulding, make core: apperance is placed in sandbox, running gate system is set, in sandbox, fill out resin sand by bottom running and carry out making casting mold, and utilize resin sand to make core; Described sandbox is two unpacking designs, comprise cope and drag box, cope is provided with the several piece of interlaced arrangement every sand cooling iron, drag box is provided with the bright chill of several piece of interlaced arrangement, be 1: 1 every the thickness of sand cooling iron and bright chill and casting thickness ratio, the spacing every between sand cooling iron is that 0.5-1 is doubly to the length every sand cooling iron; Spacing between bright chill is that 0.5-1 is doubly to the length of bright chill; Described running gate system is included in the symmetrically arranged cross gate in left and right on foundry goods, ingate and sprue, and cross gate and ingate, sprue are all arranged in cope, and sprue is perpendicular to face, cross gate place and be communicated with cross gate; Cross gate is curved, and the ingate described in several is uniformly distributed between foundry goods and cross gate, and is communicated with cross gate, foundry goods; Cast gate area ratio is S sprue: S ingate: S cross gate=1: 1.2-1.5: 0.8-1;

(3) oven dry, mould assembly: the removing surface of casting mold is clean, brushes twice with zirconium powder coating, guarantees the smooth surface that the bright chill in drag box is brushed; Dry casting mold and core, lower core, carries out mould assembly, improves bright chill and the surface temperature every sand cooling iron after mould assembly with warm-air drier baking;

(4) melting: use cupola melting molten iron;

(5) cast and peeling.