CN1163806A

CN1163806A - Non-toxic air-blowing hardening core-making method

Info

Publication number: CN1163806A
Application number: CN 97105026
Authority: CN
Inventors: 余明伟; 金广明
Original assignee: SHENYANG INST OF CASTING MATERIALS
Current assignee: SHENYANG INST OF CASTING MATERIALS
Priority date: 1997-01-15
Filing date: 1997-01-15
Publication date: 1997-11-05
Anticipated expiration: 2017-01-15
Also published as: CN1049377C

Abstract

A non-toxic core manufacture method by hardening with blowing air includes such steps as dehumidifying of air to make dew point under -20 deg.C, heating of the air to 20-100 deg.C, loading of uniformly mixed raw materials into sand shooting cylinder of core shooter, compression, forcing dry air to pass through sand core quickly hardening of sand core and taking sand core out. Its advantages are reduction of pinholes on casting, improvement of quality of casting, preventing of the generation of thermal crack, burr and vein, low cost, high productivity and improved labour condition.

Description

Non-toxic air-blowing hardening core-making method

The present invention relates to casting technology field, particularly a kind of non-toxic air-blowing hardening core-making method.

In foundry industry various air blowing coremaking are annotated and be commonly referred to as cold-box process, invented waterglass in early days and blown the CO2 core production method, because the waterglass addition is than higher, so sand core strength is low, collapsibility is bad; Invented phenolic resin CO2 cold-box process in 1967, but because intensity is lower, also never large-scale popularization is used; Nineteen sixty-eight has been invented phenol urea aldehyde triethylamine (or dimethyl amine) aerosol cold-box process, this method is widely used at present, but the content that amine gas allows in air is 25PPm, the strong impulse smell is arranged, worsen labour health condition, also owing to adopted nitrogenous binding agent to produce foundry goods, so its surface is prone to burr, the vein defective; Invented later three kinds of core manufacturing crafts that blow the SO2 cold-box again, because SO2 gas toxicity is bigger, aerial permission content is 5PPm, and to the seal request strictness of moulds of industrial equipment, tail gas needs neutralisation treatment, and the coremaking cost is higher relatively, so use not extensive at present; Invented the alkaline phenol formaldehyde resin in 1985 and blown formic acid esters aerosol cold-box process, this ester allows content in air be 100PPm, and toxicity is relatively low, does not contain N, P, S element in this adhesive system, and its shortcoming is that sand core strength is low.Though above-mentioned several cold core box core process all have advantage separately, but except that CO2 technology, that coremaking gas is is poisonous, flavor is arranged, and wherein amine and methyl esters methyl esters are the first class inflammable and explosive dangerous goods, buying, transportation and store to use and all need strict control, because majority is an organic binder bond, and used organic solvent, and divide equally explanation during cast and be placed with poison, penetrating odor gas is arranged, worsen labour health condition, the harm operating personnel are healthy, and environment is also had in various degree pollution.

The purpose of this invention is to provide nontoxic, the odorless gas of a kind of use, non-toxic adhesive can prevent effectively that foundry goods from producing the non-toxic air-blowing hardening core-making method of pore, hot tearing, burr and vein defective.

The gas that the present invention adopts is air or oxygen, or nitrogen, need before the gas blow cores through dehumidification treatments, make its dew point below-20 ℃, its dehumidifying dew point is low more, the core sclerosis is fast more, air after the dehumidifying can be regulated temperature with gas heater according to technological requirement, temperature range is 20 ℃-100 ℃, the sclerosis of the high more core of temperature is fast more, and it is fixed that the waterglass sclerosis is mainly dehydration, with the binding agent compound that stirs with core shooter core box or method consolidation by hand, again with blowing, exhaustion plate compresses core print, force drying gas is discharged from exhaust outlet by core, and the moisture in the sand grain surface waterglass film spreads in dry gas rapidly, and is taken away by air-flow, core is hardened rapidly, again core is taken out after the sclerosis.

The present invention is owing to the gas that has adopted through dehumidification treatments; between sand grain surface and dry gas stream, produce pressure reduction; can under the low condition of core gas forming amount, realize the core quick-hardening; also because coremaking binding agent addition is low, cost is low and the air blowing body is nontoxic, tasteless; do not contain harmful elements such as N, P, S; so help improving labour health condition and protection environment; reduce the bleb defective; improve casting quality; prevent that foundry goods from producing hot tearing, burr and vein defective, the advantage of also have remarkable reduction coremaking cost, raising labour productivity.

The present invention is further illustrated below in conjunction with embodiment.

Compressed air is fed cooled dehumidifier unit, dehumidify in the adsorption and dehumidification machine, or first order freeze drying, dehumidify with the associating dehumidifier of adsorption and dehumidification in the second level, a kind of method in back is applicable to the area that air humidity is bigger, first order dehumidifying can be removed most of moisture in the air, reduces the volume of adsorption plant, makes its dew point below-20 ℃; The dehumidifying after electric heater heat regulation gas temperature in 30 ° of-40 ℃ of scopes, connect the air blowing plate by electromagnetic gas valve, getting the 2kg normal sand adds in the bowl-type puddle mixer, add the 60g bonding agent again, this bonding agent is casting water glass or modified water glass, its addition accounts for the 2.5-3.5% of silica sand weight, mixed 20S shakes out, the sand compound is added Z861 core machine blasting unit, penetrate real standard " 8 " shape sample with the Z861 core shooter under 0.3-0.4MPa, Sha Kou is penetrated in sealing, opening electromagnetic gas valve makes dry air penetrate core by the air blowing plate, discharge from exhaustion plate, ventilate and opened box in 3 minutes and eject core, this sand core strength is after testing

Go out the instant tensile strength 0.8-1.0MPa of box

24h tensile strength 2.0-2.5MPa.

Claims

1, a kind of non-toxic air-blowing hardening core-making method is characterized in that:

(1), needs its dew point to be existed: below-20 ℃ before the gas blow cores through dehumidification treatments;

(2), the later air of dehumidifying heat regulation again, adjustable range is 20 ℃-100 ℃;

(3), binding agent and normal sand are mixed and made into compound, the compound that stirs is added core shooter blasting unit or method consolidation by hand, compress core print with blowing exhaustion plate, force drying gas is discharged from exhaust outlet by core, and core is taken out core after the sclerosis rapidly again.

2, non-toxic air-blowing hardening core-making method according to claim 1, the best heat regulation scope of the air after it is characterized in that dehumidifying is 30 °-40 ℃.

3, non-toxic air-blowing hardening core-making method according to claim 1 is characterized in that binding agent is casting water glass or modified water glass, and its addition accounts for the 2.5-3.5% of silica sand weight.

4, non-toxic air-blowing hardening core-making method according to claim 1 is characterized in that blow cores gas can be air or oxygen or nitrogen.

5, non-toxic air-blowing hardening core-making method according to claim 1 is characterized in that blow cores gas can feed cooled dehumidifier unit, the dehumidifying of adsorption and dehumidification machine, or first order freeze drying, dehumidifies with the associating dehumidifier of adsorption and dehumidification in the second level.