CN103028700A

CN103028700A - Blind riser

Info

Publication number: CN103028700A
Application number: CN 201110297882
Authority: CN
Inventors: 浦巧生
Original assignee: Wujiang Hydraulic Components Foundry Co Ltd
Current assignee: Wujiang Hydraulic Components Foundry Co Ltd
Priority date: 2011-10-08
Filing date: 2011-10-08
Publication date: 2013-04-10

Abstract

The invention relates to a blind riser, which comprises a side wall, a top wall and an air outlet hole arranged in the top wall and also comprises a base, wherein the whole body of the base is in a cone sleeve shape with the inner cone surface, the base is made of heat insulation materials and is detachably connected with the side wall, an upper opening of the inner cone surface is matched with the bottom of the blind riser, the radius of a lower opening of the inner cone surface is smaller than the radius of the upper opening, an annular bulge projected in the downward direction is formed around the air outlet hole by the top wall, and the annular bulge is in an inclined slope shape. The blind riser has the advantages that the base made of the heat insulation materials is adopted, in addition, the inner cone surface structure is adopted, the base and the side wall are detachably connected, a thickened structure is adopted around the air outlet hole, the local folding resistance intensity around the air outlet hole is improved, and the process yield can be greatly improved.

Description

Blind riser

Technical field

The present invention relates to a kind of blind riser.

Background technology

In casting process, after pouring metal melt enters casting mold, because cooled and solidified, transferred to solid-stately by liquid state, produce volume contraction.When volume contraction can not get molten metal and replenishes, after solidifying, the larger position of modulus can produce shrinkage cavity and porosity in the foundry goods.For the larger casting alloy of those volume contractions, this defective often occurs.Shrinkage cavity and porosity can reduce foundry goods compactness, reduce the net sectional area of foundry goods, mechanical property is reduced greatly, therefore must manage control and solidify, prevent that defective from producing.Use rising head, be at present in casting industry control solidify, effective, the most universal technological measure of compensate for shrinkage.

The main effect of rising head is feeding, produces shrinkage cavity to prevent parts.Rising head also has following effect:

1) scavenging action.A large amount of gases during cast in the die cavity are by rising head successfully outside the discharge type;

2) collection slag effect.Because rising head is located at cast top usually, the slag come-up is gathered in the rising head;

3) rising head can be used as liquid metal and fills with sign of die cavity etc.

Rising head will reach the purpose of feeding foundry goods, must satisfy following primary condition:

1) must be within effective feeding distance;

2) modulus of rising head must be greater than the modulus of foundry goods, and namely the setting time of rising head must be longer than the setting time of foundry goods;

3) to there be the molten metal of q.s to supply with feeding foundry goods usefulness in the rising head;

4) Feeding channel between rising head and foundry goods will guarantee unimpeded at solidificating period.

Whether rising head is covered by molding sand according to its top can be divided into open riser and blind riser, open riser is because need to add from the outside coverture, institute thinks that cylinder tube shape or circular cone are tubular, and blind riser is not because need to add coverture in sand mold inside, so only leave venthole at the top.

Common sand mold rising head is because heat-sinking capability is stronger, and heat conduction and the thermal radiation loss of riser metal are large, and setting rate is fast, and its feeding efficiency only is 10～14%, and most riser metals are actually a kind of reactive power consumption.In order to improve feeding efficiency, effective measures are that riser metal is incubated, produced thus insulated feeder, so-called insulated feeder is made by the material with good accumulation of heat and fire resistance, adopt insulated feeder can reduce heat loss, prolong the molten metal setting time, enlarge Feeding channel, the amount of metal that the feeding effect does not directly occur is reduced to very low limit, thereby improve feeding efficiency and product yield.

Blind riser in the existing insulated feeder, its main body comprises sidewall and roof, is provided with venthole at roof, and general employing waits the wall thickness structure, and venthole is positioned at the extreme higher position.During cast, molten metal enters die cavity, a large amount of gases in the die cavity are by outside the venthole ground discharge type of blind riser, in gas discharge process, gas in the die cavity is subjected to squeezing of molten metal to pour blind riser first, so because less high pressure that can produce far above external atmosphere pressure of the venthole of blind riser, moreover when gases are heated, they expand in the die cavity has more improved air pressure in the blind riser, although that gas pressure is all directions is identical, but because the main direction of gas flow makes progress, so the roof of blind riser especially venthole position will bear gas pressure much larger than sidewall, and adopt the above-mentioned wall thickness structure that waits, the rupture strength at each position of blind riser is identical, thus exist the venthole position easily cracking come off and affect the problem of casting quality, if the thicker rising head of employing wall thickness is wasted again material.In addition, when feeding, molten metal easily condenses into shell near rising head main body top, venthole, and this has also reduced casting quality.

In addition, for reducing the amount of labour of cutting rising head, people arrange cameron core between insulated feeder and pattern, feeding neck hole is established at the cameron core center, problem is that cameron core does not possess heat insulation effect, solidifies at place, feeding neck hole for avoiding molten metal, cameron core thickness is subjected to very big restriction, and the product yield that can improve is limited.

Summary of the invention

The technical problem that the present invention solves is, a kind of blind riser is provided, and improved local rupture strength and product yield around the venthole.

The technical solution used in the present invention is:

A kind of blind riser, comprise sidewall, roof and be located at venthole on the roof, comprise that also whole is the base with tapered sleeve shape of internal conical surface, base is made by heat-insulating heat-preserving material, base and sidewall removably connect, the upper shed of internal conical surface and the bottom of blind riser are complementary, and the under shed radius of internal conical surface is less than the upper shed radius; Described roof is formed with the annular protrusion of downward protrusion around venthole, this annular protrusion is ramped shaped.

Further, the slope angle of described annular protrusion is that 25 °-40 ° and its end and venthole junction are set to chamfering.

Beneficial effect of the present invention is:

The present invention uses heat-insulating heat-preserving material to make base and adopts the internal conical surface structure, and base and sidewall removably connect, and adopt structure thicker around the venthole, has improved venthole local rupture strength on every side, can increase substantially product yield.

Description of drawings

Fig. 1 is structural representation of the present invention.

Fig. 2 is the structural representation at chamfering of the present invention place.

The specific embodiment

The invention will be further described below in conjunction with drawings and Examples.

Embodiment:

As shown in drawings, a kind of blind riser, comprise sidewall 1, roof 2 and be located at venthole 4 on the roof, comprise that also whole is the base 3 with tapered sleeve shape of internal conical surface, base is made by heat-insulating heat-preserving material, base 3 removably connects with sidewall 1, and the upper shed of internal conical surface and the bottom of blind riser are complementary, and the under shed radius of internal conical surface is less than the upper shed radius; Described roof 2 is formed with the annular protrusion 5 of downward protrusion around venthole 4, this annular protrusion is ramped shaped.

Annular protrusion is set has improved venthole local rupture strength on every side, so that the problem that venthole ftractures or comes off on every side in use can not appear in insulated feeder, and because annular protrusion is to protrude downwards, so that the position of venthole no longer is the extreme higher position of rising head roof, the extreme higher position of rising head roof is at the contact root of annular protrusion with the rising head roof, gas in the die cavity can be subject to obstruction to a certain degree in discharge process like this, prolonged so to a certain extent the time of staying of gas in insulated feeder, can play increases gas pressure and the effect that reduces the interior gas of rising head and ambient atmos heat exchanger effectiveness in the rising head, the former can increase the feeding pressure of rising head inner metal liquid, the latter can prolong molten metal setting time in the rising head, both can improve the feeding efficiency of rising head.In addition, in the base, the upper shed radius that internal conical surface can be set is that 2 times of under shed radius, cone angle are 90 °; During cast, molten metal enters die cavity, a large amount of gases in the die cavity are by outside the insulated feeder ground discharge type, molten metal immerses in the insulated feeder, when the molten metal in the die cavity solidifies, and the molten metal feeding in the insulated feeder, after the foundry goods moulding, riser metal forms necking down at base position, and convenient cutting has also improved product yield simultaneously.

Further, the slope angle of described annular protrusion 5 is that 25 °-40 ° and its end and venthole 4 junctions are set to chamfering 6.Annular protrusion is set as ramped shaped can reduce the obstruction that annular protrusion is discharged gas, avoid it to ftracture greatly and come off because being subject to impacting, affect casting quality, improving feeding efficiency and avoiding between the annular protrusion cracking a fabulous balance being arranged when slope angle is made as 30 °; Chamfering is set, and can to avoid molten metal be to condense in the venthole porch in annular protrusion end and venthole junction, reduces the impairment venthole area that condenses, affects product yield.

Claims

1. blind riser, it is characterized in that, comprise sidewall, roof and be located at venthole on the roof, comprise that also whole is the base with tapered sleeve shape of internal conical surface, base is made by heat-insulating heat-preserving material, base and sidewall removably connect, and the upper shed of internal conical surface and the bottom of blind riser are complementary, and the under shed radius of internal conical surface is less than the upper shed radius; Described roof is formed with the annular protrusion of downward protrusion around venthole, this annular protrusion is ramped shaped.

2. blind riser as claimed in claim 1 is characterized in that, the slope angle of described annular protrusion is that 25 °-40 ° and its end and venthole junction are set to chamfering.