CN102794446A - Casting technology preventing ductile irons from suffering shrinkage cavity and shrinkage porosity - Google Patents

Abstract

The invention discloses a casting technology which can prevent ductile irons from suffering shrinkage cavities and shrinkage porosity. The technology is characterized by comprising the following steps of preparing materials; melting materials to obtain molten iron; performing casting; and examining the results and the qualities. The technology provided in the invention is simple. A casting sink-head-free technology is then achieved. The castings which will not suffer shrinkage porosity defects from the surfaces to the central parts have a compact structure. By means of the technology, the technical product yield rate is improved to 96.9 percent from 74.4 percent by an original sink-head technology. The technical product yield rate and the technical product quality are thus significantly improved.

Description

Prevent the casting technique of magnesium iron spare shrinkage cavity (pine)

Technical field:

The present invention relates to a kind of casting technique that prevents magnesium iron spare shrinkage cavity (pine).

Background technology:

At present, the shrinkage cavity of magnesium iron spare, shrinkage defect are the major reasons that magnesium iron spare produces waste product, and existing limit emits technology when producing, because foundry goods graphitization expansion power has loose bowels to rising head in a large number, causing can not be from feeding, and cause the frequent appearance property shrinkage defect that looses.

Summary of the invention:

The objective of the invention is provides a kind of casting technique that prevents magnesium iron spare shrinkage cavity (pine) in order to overcome above deficiency.

The object of the invention is realized through following technical scheme: a kind of casting technique that prevents magnesium iron spare shrinkage cavity (pine) may further comprise the steps:

A, get the raw materials ready; According to the requirement of the foundry goods trade mark, select the suitable pig iron.

B, melting molten iron;

C, casting; The cast temperature scope is 1300 ℃-1350 ℃; Actual casting time is no more than 120s; Ingate adopts multiple tracks, evenly gets into molten iron, and shape should guarantee to solidify as early as possible with flat thin or narrow dark running channel; Its thickness generally is no more than 15mm, and total interfacial area of venthole must be greater than the minimum choked flow area of casting system; Casting strength wants height and even, and fitness reaches more than 85, and the rigidity of sandbox and the confinement of mould assembling will be got well, and the carbon content of molten iron is high more good more.

D, assay and quality;

The present invention compared with prior art has the following advantages:

The present invention is through the foundry goods of this processes; Realized the non-riser technology of foundry goods; From the top layer to the centre, shrinkage defect, tissue tight can not appear; Product yield brings up to 96.9% from original 74.4% of the rising head technology that has, and has improved the quality that product yield and technology are produced greatly.

The specific embodiment:

In order to deepen to understanding of the present invention, will combine embodiment that the present invention is made further detailed description below, this embodiment only is used to explain the present invention, does not constitute the qualification to protection domain of the present invention.

The present invention relates to a kind of specific embodiment that prevents the casting technique of magnesium iron spare shrinkage cavity (pine), may further comprise the steps:, select the suitable pig iron at first according to the requirement of the foundry goods trade mark; Again the pig iron is dissolved and is smelt molten iron,, and then cast; The cast temperature scope is 1300 ℃-1350 ℃, under the prerequisite that does not produce the cold shut defective, takes off limit as far as possible; Actual casting time is no more than 120s, and ingate adopts multiple tracks, evenly gets into molten iron, and shape is with flat thin or narrow dark running channel; Should guarantee to solidify as early as possible, its thickness generally is no more than 15mm, and total interfacial area of venthole must be greater than the minimum choked flow area of casting system; Casting strength wants height and even, and fitness reaches more than 85, and the rigidity of sandbox and the confinement of mould assembling will be got well, in order to avoid runout, the carbon content of molten iron is high more good more, after casting finishes, unpacks foundry goods is carried out quality inspection.

Through the foundry goods of this processes, realized the non-riser technology of foundry goods, from the top layer to the centre, shrinkage defect can not appear, tissue tight, product yield brings up to 96.9% from original 74.4% of the rising head technology that has.

Claims (1)

1. a casting technique that prevents magnesium iron spare shrinkage cavity (pine) is characterized in that, may further comprise the steps:

A, get the raw materials ready; According to the requirement of the foundry goods trade mark, select the suitable pig iron.

B, melting molten iron;

C, casting; The cast temperature scope is 1300 ℃-1350 ℃; Actual casting time is no more than 120s; Ingate adopts multiple tracks, evenly gets into molten iron, and shape should guarantee to solidify as early as possible with flat thin or narrow dark running channel; Its thickness generally is no more than 15mm, and total interfacial area of venthole must be greater than the minimum choked flow area of casting system; Casting strength wants height and even, and fitness reaches more than 85, and the rigidity of sandbox and the confinement of mould assembling will be got well, and the carbon content of molten iron is high more good more.

D, assay and quality.