CN104057025A

CN104057025A - Casting technology for high-chromium iron double-suction impeller

Info

Publication number: CN104057025A
Application number: CN201410304201.0A
Authority: CN
Inventors: 薛铁山
Original assignee: 薛铁山
Priority date: 2014-06-30
Filing date: 2014-06-30
Publication date: 2014-09-24

Abstract

The invention discloses a casting technology for a high-chromium iron double-suction impeller and belongs to the field of casting. The casting technology is characterized by comprising the following steps that firstly, two pulling ribs are added on a cracked part of a blade, in order to effectively feed a lower cover plate, three side dead heads are added, and the side dead heads are 160 mm in diameter and 400 mm in height; secondly, modeling and core manufacturing are conducted; thirdly, brushing and box combining are conducted; fourthly, smelting and casting are conducted; fifthly, postprocessing of a casting is conducted. According to the high-chromium iron double-suction impeller produced with the technology, the crossed root between the blade of the casting and the cover plate is not cracked, a spindle nose part is not provided with air holes, the lower cover plate is not provided with shrinkage cavities, and the technology is simple in operation and convenient to popularize.

Description

A kind of casting technique of rich chromium cast iron double-entry impeller

Technical field

The invention belongs to casting field, relate in particular to a kind of casting technique of rich chromium cast iron double-entry impeller.

Background technology

Because impeller is as flow passage components, solution is more severe to impeller corrosivity, rich chromium cast iron belongs to good wear resistant corrosion resistant material, but its fragility is more intense, its casting character is poorer than common rich chromium cast iron, easily takes out and splits, and foundary loss rate is higher, and double-entry impeller complex structure, casting difficulty is larger; The rich chromium cast iron double-entry impeller foundry goods that at present technique is produced is that blade intersects with cover plate that root is easy to crack, spindle nose partly has pore and lower cover to have shrinkage cavity generation.

Summary of the invention

The casting technique that the object of this invention is to provide a kind of rich chromium cast iron double-entry impeller, solve rich chromium cast iron double-entry impeller foundry goods blade that prior art processes produces and cover plate and intersected the problem that root is easy to crack, spindle nose partly has pore and lower cover to have shrinkage cavity to produce

In order to achieve the above object, by the following technical solutions, a kind of casting technique of rich chromium cast iron double-entry impeller, comprises the following steps in the present invention.

A, blade cracking position is increased and draws rib 2 roads; For effective feeding lower cover, increase by three of side risers, side riser diameter is 160mm, height 400mm.

B, moulding, coremaking; Adopt 25 tons of mobile flow mixers to carry out mulling operation, branch addition is 1%, and curing agent is 0.5%, guarantees that 24 hours dry strength of casting mold are not less than 1.2; First make nowel, sand mold is carried out to abundant consolidation, the chromite sand of chill and mulling is put into the position that needs Quench, then covering resin sand, places running gate system and rising head according to process stipulation while making top box, guarantees that dead head washes away root emphasis consolidation; Spend 15 minutes and treat sand mold hard later mould turnover molding; During impeller coremaking, cover plate and core box are compressed, place boom hoisting, root of blade is also taked to cover chromite sand, guarantee that thickness is greater than 100mm, impeller SMIS also adopts chromite sand, and in centre, adds chill rod.

C, brushing, mould assembling, before brushing, casting mold and core are carried out to reconditioning, blow floating sand, use alcohol zircon flour coating, before brushing, coating is stirred, swabbing is uniform and smooth, after brushing, light, coating current mark and nest ash position are polished, coating layer thickness 0.5～1mm, easily coating is brushed at scab position twice, before mould assembling, with blowtorch, toast 10 ~ 15 minutes, whether mould assembling checks fuse position correct after core at present, and before mould assembling, want tryoff, inspection has or not inclined to one side case, whether wall thickness meets, cast gate, whether core is tight around, whether core is correct, casting mold has or not and damages by pressure, drop phenomenon.

D, smelting and pouring; Before cast, with air-heater, at 200 ℃, casting mold is toasted 2 hours, with this, prevent the sand mold moisture absorption, reduce resin gas forming amount in sand mold; Adopt 1 ton of intermediate frequency furnace melting, during melting, first add Gao Ge, then add low chromium and steel scrap, precious alloy copper nickel molybdenum is treated to add after molten iron is melting, reduce scaling loss as far as possible, after fusing, use spectrophotometer composition, after composition is qualified, molten iron temperature in stove is brought up to 1560 ~ 1590 ℃, before coming out of the stove, adopt 0.1% inovulant to carry out inoculation, take the method that low temperature waters soon to reduce pouring temperature, improve poring rate, pouring temperature is 1430 ~ 1450 ℃, and poring rate is 30 ~ 50 seconds.

E, foundry goods post processing; Double-entry impeller casting structure torsion resistance is larger, presses case 5 ~ 7 days, treat casting temperature little 50 ℃ following can shake out, rich chromium cast iron material fragility is large, should first heat treatment remove internal stress, then could cut dead head.

The invention has the beneficial effects as follows: adopt the rich chromium cast iron double-entry impeller foundry goods blade that this explained hereafter goes out to intersect root without cracking, spindle nose part pore-free with cover plate, lower cover also produces without shrinkage cavity, and this process operation is simple, is convenient to promote.

The specific embodiment

Below by specific embodiment, further describe the present invention, but invention is not only confined to following examples; A casting technique for rich chromium cast iron double-entry impeller, comprises the following steps.

A, blade cracking position is increased and draws rib 2 roads; For effective feeding lower cover, increase by three of side risers, side riser diameter is 160mm, height 400mm, first makes nowel during moulding, sand mold is carried out to abundant consolidation, the chromite sand of preprepared chill and mulling is put into the position that needs Quench, then covering resin sand; While making top box, according to process stipulation, place running gate system and rising head etc., and guarantee that dead head washes away root emphasis consolidation; Spend 15 minutes and treat sand mold hard later mould turnover molding; During impeller coremaking, cover plate and core box are compressed, place boom hoisting, root of blade is also taked to cover chromite sand, guarantee that thickness is greater than 100mm, impeller SMIS also adopts chromite sand, and in centre, adds chill rod.

D, smelting and pouring; Before cast, with air-heater, at 200 ℃, casting mold is toasted 2 hours, with this, prevent the sand mold moisture absorption, reduce resin gas forming amount in sand mold; Adopt 1 ton of intermediate frequency furnace melting, during melting, first add Gao Ge, then add low

Chromium and steel scrap, precious alloy copper nickel molybdenum is treated to add after molten iron is melting, reduce scaling loss as far as possible, after fusing, use spectrophotometer composition, after composition is qualified, molten iron temperature in stove is brought up to 1560 ~ 1590 ℃, before coming out of the stove, adopt 0.1% inovulant to carry out inoculation, take the method that low temperature waters soon to reduce pouring temperature, improve poring rate, pouring temperature is 1430 ~ 1450 ℃, and poring rate is 30 ~ 50 seconds.

The present invention does not describe part in detail, is those skilled in the art of the present technique's known technology.

Claims

1. a casting technique for rich chromium cast iron double-entry impeller, is characterized in that comprising the following steps:

A, blade cracking position is increased and draws rib 2 roads; For effective feeding lower cover, increase by three of side risers, side riser diameter is 160mm, height 400mm;

B, moulding, coremaking; Adopt 25 tons of mobile flow mixers to carry out mulling operation, branch addition is 1%, and curing agent is 0.5%, guarantees that 24 hours dry strength of casting mold are not less than 1.2; First make nowel, sand mold is carried out to abundant consolidation, the chromite sand of chill and mulling is put into the position that needs Quench, then covering resin sand, places running gate system and rising head according to process stipulation while making top box, guarantees that dead head washes away root emphasis consolidation; Spend 15 minutes and treat sand mold hard later mould turnover molding; During impeller coremaking, cover plate and core box are compressed, place boom hoisting, root of blade is also taked to cover chromite sand, guarantee that thickness is greater than 100mm, impeller SMIS also adopts chromite sand, and in centre, adds chill rod;

C, brushing, mould assembling, before brushing, casting mold and core are carried out to reconditioning, blow floating sand, use alcohol zircon flour coating, before brushing, coating is stirred, swabbing is uniform and smooth, after brushing, light, coating current mark and nest ash position are polished, coating layer thickness 0.5～1mm, easily coating is brushed at scab position twice, before mould assembling, with blowtorch, toast 10 ~ 15 minutes, whether mould assembling checks fuse position correct after core at present, and before mould assembling, want tryoff, inspection has or not inclined to one side case, whether wall thickness meets, cast gate, whether core is tight around, whether core is correct, casting mold has or not and damages by pressure, drop phenomenon,

D, smelting and pouring; Before cast, with air-heater, at 200 ℃, casting mold is toasted 2 hours, with this, prevent the sand mold moisture absorption, reduce resin gas forming amount in sand mold; Adopt 1 ton of intermediate frequency furnace melting, during melting, first add Gao Ge, then add low chromium and steel scrap, precious alloy copper nickel molybdenum is treated to add after molten iron is melting, reduce scaling loss as far as possible, after fusing, use spectrophotometer composition, after composition is qualified, molten iron temperature in stove is brought up to 1560 ~ 1590 ℃, before coming out of the stove, adopt 0.1% inovulant to carry out inoculation, take the method that low temperature waters soon to reduce pouring temperature, improve poring rate, pouring temperature is 1430 ~ 1450 ℃, and poring rate is 30 ~ 50 seconds;