CN104209462A

CN104209462A - Method of eliminating carbon residue defect and recarburization defect of lost foam casting

Info

Publication number: CN104209462A
Application number: CN201410435845.3A
Authority: CN
Inventors: 刘成文
Original assignee: SHANXI MOFAN MACHINERY MANUFACTURING Co Ltd
Current assignee: SHANXI MOFAN MACHINERY MANUFACTURING Co Ltd
Priority date: 2014-09-01
Filing date: 2014-09-01
Publication date: 2014-12-17

Abstract

The invention relates to a method of eliminating carbon residue defect and recarburization defect of lost foam casting. The method comprises the following technological processes: pre-foaming polystyrene beads, aging the pre-foamed beads, forming blank patterns, drying the blank patterns, combining the blank patterns, brushing paint, drying the blank patterns coated with the paint, burying in a box to compact, pouring molten iron and taking out from the box and polishing. During pre-foaming polystyrene beads, 4-6 % of calcium peroxide powder is mixed with an EPS or EPMMA material, and the beads mixed with calcium peroxide powder are mixed uniformly and pre-foamed under conditions of an air pressure of 0.4-0.6 MPa, a steam temperature of 85-100 oC and a foaming density of 22-26 g/L. During the step of pouring molten iron, a negative pressure of -0.05 to -0.06 MPa is maintained for 20 min to oxidize carbon in the material to generate CO2 and CO. CO2 and CO are pumped out to realize the aim of decarbonizing.

Description

Eliminate the method for evaporative pattern foundry goods carbon slag defect and carburetting defect

Technical field

The invention belongs to Technology of EPC field, be specifically related to the method eliminating evaporative pattern foundry goods carbon slag defect and carburetting defect.

Background technology

Because in vanishing mold moulding material EPS and EPMMA, bead phosphorus content is up to 92%, minimum is also 60%, often cause evaporative pattern foundry goods distinctive defect phacolith slag (particularly G. Iron Castings) and carburetting (low-carbon (LC) steel part), for eliminating these defects, what other manufacturer had takes first to burn rear pouring technique, some employing ghost negative pressure castings, copolymerization material (EPMMA) molding that some employing phosphorus content are low, what have takes hollow running channel and hollow mold (to thick strip or thick major part), the employing interpolation ammonium chloride also had or the coating of caustic soda or boric acid prevent mild steel carburetting, these method processing steps are complicated, cost is high, unfavorable being used in this area is promoted the use of.

Summary of the invention

The present invention is exactly to solve the defect eliminating defect phacolith slag (particularly G. Iron Castings) and the carburetting (low-carbon (LC) steel part) existed in evaporative pattern foundry goods, and proposes the method eliminating evaporative pattern foundry goods carbon slag defect and carburetting defect.

The technical solution used in the present invention: the method eliminating evaporative pattern foundry goods carbon slag defect and carburetting defect, comprise following technological process: send out polystyrene bead in advance, by the bead slaking after sending out in advance, white mold forming, Bai Mo is dried, white die combination, swabbing, the white mould coating coating is dried, bury case jolt ramming, pouring molten iron, outlet is polished, during pre-polystyrene bead, 4-6% peroxidating calcium powder is admixed in EPS or EPMMA material, the bead mixing well calcium oxide powder is stirred and plays the part of evenly, be 0.4 ~ 0.6MPa in air pressure, vapor (steam) temperature is 85 ~ 100 DEG C, expansion density is sent out in advance under the condition of 22 ~ 26g/L, when pouring molten iron step, pass through the negative pressure of-0.05 ~-0.06MPa, pressurize 20 minutes, the carbon in material is generated CO2 and CO through oxidation and is pumped, to reach the object of de-carbon.

The present invention compared with prior art its beneficial effect is by adding peroxidating calcium powder in evaporative pattern casting process step in: the present invention, when not increasing technology difficulty and cost, can be easy to solve the defect phacolith slag (particularly G. Iron Castings) that exists in evaporative pattern foundry goods and carburetting (low-carbon (LC) steel part) problem, simple to operate, the comprehensive advantage of efficient and low cost.

Detailed description of the invention

embodiment 1

Eliminate the method for evaporative pattern foundry goods carbon slag defect and carburetting defect, comprise the following steps: (1) sends out polystyrene bead in advance: in EPS material, admix 4% peroxidating calcium powder, the bead mixing well calcium oxide powder is stirred and plays the part of evenly, be 0.4MPa in air pressure, vapor (steam) temperature is 85 DEG C, and expansion density is sent out in advance under the condition of 22g/L;

(2) will send out polystyrene bead slaking in advance rear, region, slaking storehouse keeps ventilating, 4 hours maturation process time;

(3) white mold forming, by mould and die preheating to 50 DEG C, matched moulds, reinforced, steam pressure remain on 0.4MPa, and time controling is at 50s;

(4) white mould is dried, and is dried by white mould under temperature 50 C condition;

(5) white die combination, is coated with cold glue or PUR bonding by model die joint;

(6) the white mould surface brush lost foam casting fireproof coating will made, coating layer thickness is 1mm;

(7) dried by the white mould coating coating, temperature controls at 50 DEG C;

(8) bury case jolt ramming, sand fills up 3 seconds rear jolt ramming time, and sandbox top plastic sheeting seals, and cup is put at cast gate place;

(9) pouring molten iron, molten iron temperature controls, at 1430 DEG C, to vacuumize during cast in case, negative pressure at-0.05MPa, pressurize 20 minutes;

(10) after cast, insulation is unpacked after 60 minutes again;

(11) clear up, smooth with grinder buffing, the foundry goods of acquisition is without carburetting defect.

Embodiment 2

Eliminate the method for evaporative pattern foundry goods carbon slag defect and carburetting defect, comprise the following steps: (1) sends out polystyrene bead in advance: in EPMMA material, admix 5% peroxidating calcium powder, the bead mixing well calcium oxide powder is stirred and plays the part of evenly, be 0.5MPa in air pressure, vapor (steam) temperature is 90 DEG C, and expansion density is sent out in advance under the condition of 24g/L;

(2) will send out polystyrene bead slaking in advance rear, region, slaking storehouse keeps ventilating, 5 hours maturation process time;

(3) white mold forming, by mould and die preheating to 60 DEG C, matched moulds, reinforced, steam pressure remain on 0.5MPa, and time controling is at 60s;

(4) white mould is dried, and is dried by white mould under temperature 53 DEG C of conditions;

(6) the white mould surface brush lost foam casting fireproof coating will made, coating layer thickness is 1.2mm;

(7) dried by the white mould coating coating, temperature controls at 53 DEG C;

(8) bury case jolt ramming, sand fills up 4 seconds rear jolt ramming time, and sandbox top plastic sheeting seals, and cup is put at cast gate place;

(9) pouring molten iron, molten iron temperature controls, at 1450 DEG C, to vacuumize during cast in case, negative pressure at-0.06MPa, pressurize 20 minutes;

(10) after cast, insulation is unpacked after 80 minutes again;

Embodiment 3

Eliminate the method for evaporative pattern foundry goods carbon slag defect and carburetting defect, comprise the following steps: (1) sends out polystyrene bead in advance: in EPMMA material, admix 6% peroxidating calcium powder, the bead mixing well calcium oxide powder is stirred and plays the part of evenly, be 0.6MPa in air pressure, vapor (steam) temperature is 100 DEG C, and expansion density is sent out in advance under the condition of 26g/L;

(2) will send out polystyrene bead slaking in advance rear, region, slaking storehouse keeps ventilating, 6 hours maturation process time;

(3) white mold forming, by mould and die preheating to 70 DEG C, matched moulds, reinforced, steam pressure remain on 0.6MPa, and time controling is at 70s;

(4) white mould is dried, and is dried by white mould under temperature 55 DEG C of conditions;

(6) the white mould surface brush lost foam casting fireproof coating will made, coating layer thickness is 1.3mm;

(7) dried by the white mould coating coating, temperature controls at 55 DEG C;

(8) bury case jolt ramming, sand fills up 5 seconds rear jolt ramming time, and sandbox top plastic sheeting seals, and cup is put at cast gate place;

(9) pouring molten iron, molten iron temperature controls, at 1460 DEG C, to vacuumize during cast in case, negative pressure at-0.06MPa, pressurize 20 minutes;

(10) after cast, insulation is unpacked after 120 minutes again;

Claims

1. eliminate the method for evaporative pattern foundry goods carbon slag defect and carburetting defect, comprise following technological process: send out polystyrene bead in advance, by the bead slaking after sending out in advance, white mold forming, Bai Mo is dried, white die combination, swabbing, the white mould coating coating is dried, bury case jolt ramming, pouring molten iron, outlet is polished, it is characterized in that: during pre-polystyrene bead, 4-6% peroxidating calcium powder is admixed in EPS or EPMMA material, the bead mixing well calcium oxide powder is stirred and plays the part of evenly, be 0.4 ~ 0.6MPa in air pressure, vapor (steam) temperature is 85 ~ 100 DEG C, expansion density is sent out in advance under the condition of 22 ~ 26g/L, when pouring molten iron step, pass through the negative pressure of-0.05 ~-0.06MPa, pressurize 20 minutes, the carbon in material is generated CO2 and CO through oxidation and is pumped, to reach the object of de-carbon.