CN103567368A - Molding sand with high wet-heat tensile strength and preparation method thereof - Google Patents

Abstract

The invention discloses molding sand with high wet-heat tensile strength and a preparation method thereof. The molding sand is prepared from the following raw materials in parts by weight: 80-100 parts of river sand, 20-30 parts of forsterite, 10-15 parts of hectorite, 8-12 parts of rice bran, 5-10 parts of tricalcium aluminate, 3-6 parts of gypsum powder, 1.5-2.5 parts of hydroxypropyl methyl cellulose ether, 3-5 parts of steel fibers, 2-3 parts of guar gum, 1-2 parts of triethanolamine, 2-3 parts of tetraethylene glycol methyl methacrylate, 3-6 parts of composite powder and 1-6 parts of water. The molding sand disclosed by the invention adopts the river sand and the forsterite as the main materials, is supplemented with the materials such as hectorite, steel fibers and tricalcium aluminate, so that wet tensile strength and heat resistance of the molding sand are improved, and therefore, sand inclusion resistance of the molding sand is obviously improved, the defects such as sand inclusion and scab due to insufficient wet-heat tensile strength of the molding sand on the surface of a casting piece are avoided, and the yield of the casting piece is improved.

Description

High hot green tensile strength molding sand and preparation method thereof

Technical field

the present invention relates to a kind of molding sand and preparation method thereof, be specifically related to a kind of high hot green tensile strength molding sand and preparation method thereof.

Background technology

Molding sand is in casting process, to be used for the material of moulding, generally by Modeling Materials such as Foundry sand, moulding sand binder and additional things, is mixed according to a certain percentage.The quality of molding sand directly affects the performance of foundry goods, as sand holes, pore, burning into sand, scab, defects i.e.cracks.When the clay green-sand of prior art is poured into a mould thick massive plate class foundry goods, because molding sand hot green tensile strength is inadequate, foundry goods easily surface produces scab class defect.

Summary of the invention

The object of the invention is to, for the low shortcoming of existing molding sand sand hot green tensile strength, provides a kind of high hot green tensile strength molding sand and preparation method thereof, avoids cast(ing) surface to occur scab class defect.

For achieving the above object, technical scheme of the present invention is as follows:

A hot green tensile strength molding sand, is comprised of the raw material of following weight portion: river sand 80-100, forsterite 20-30, hectorite 10-15, rice bran 8-12, tricalcium aluminate 5-10, land plaster 3-6, hydroxypropyl methyl cellulose ether 1.5-2.5, steel fibre 3-5, guar gum 2-3, triethanolamine 1-2, tetraethylene-glycol dimethylacrylate 2-3, composite powder 3-6, water 4-8;

The preparation method of described composite powder is as follows: a, take perlite, fluorite and barite by weight 4-8:3-5:2-3, mix, pulverized 100-150 mesh sieve, then add water making beating and make the slurry that solid content is 50-60%, high speed ball milling 2-3h, spraying is dry; In b, the dried powder of spraying, add the coconut shell flour of 3-5%, the coal dust of the calcirm-fluoride of 2-3%, 1-2% and the yittrium oxide of 0.4-0.8%, 850-880 ℃ of calcining 30-40min, be warming up to again 1200-1250 ℃ of calcining 2-3h, shrend, then be placed in the hydrochloric acid solution that concentration is 15-20%, be heated to boiling speed lapping 20-30min, the sodium hydroxide solution regulator solution PH that is 10-15% by concentration is again to neutral, under 50-70 ℃ of bath temperature, stir 10-15min, filter, with distilled water, clean filter residue, dry; In powder after c, above-mentioned oven dry, add the sodium phosphate trimer of 2-3%, the jade powder of the soybean oil of the calcium stearate of 1-2%, 3-5%, 2-3% and N-(β-aminoethyl of 0.5-1%)-γ-aminopropyltrimethoxysilane, speed lapping 5-10min, dry, cross 200-300 mesh sieve.

The preparation method of high hot green tensile strength molding sand, comprises the following steps:

(1), by river sand, forsterite, hectorite, rice bran co-grinding, after mistake 200-300 mesh sieve, with tricalcium aluminate, land plaster, steel fibre, composite powder, be dry mixed 2-3min;

(2) add water, hydroxypropyl methyl cellulose ether, guar gum, triethanolamine, tetraethylene-glycol dimethylacrylate, wet mixing 3-5min, shakes out again.

Beneficial effect of the present invention:

It is major ingredient that the present invention adopts river sand, forsterite, be aided with the raw materials such as hectorite, steel fibre, tricalcium aluminate, green tensile strength and the heat resistance of molding sand have been improved, thereby obviously improve the anti-sand carrying capacity of molding sand, the scab class defect of avoiding cast(ing) surface to cause not because of molding sand hot green tensile strength, improves casting yield.

The specific embodiment

a hot green tensile strength molding sand, is comprised of the raw material of following weight (kg): river sand 90, forsterite 20, hectorite 15, rice bran 10, tricalcium aluminate 8, land plaster 4, hydroxypropyl methyl cellulose ether 2, steel fibre 4, guar gum 2, triethanolamine 1.5, tetraethylene-glycol dimethylacrylate 2, composite powder 4, water 6;

The preparation method of described composite powder is as follows: a, take perlite, fluorite and barite by weight 6:4:2, mix, pulverized 150 mesh sieves, then adding water making beating, to make solid content be 50% slurry, high speed ball milling 2h, and spraying is dry; In b, the dried powder of spraying, add 4% coconut shell flour, 2% calcirm-fluoride, 1% coal dust and 0.6% yittrium oxide, 860 ℃ of calcining 35min, be warming up to 1240 ℃ of calcining 2h, shrend, is then placed in concentration and is 18% hydrochloric acid solution again, be heated to boiling speed lapping 25min, the sodium hydroxide solution regulator solution PH that is 15% by concentration again, to neutral, stirs 15min under 60 ℃ of bath temperatures, filters, with distilled water, clean filter residue, dry; In powder after c, above-mentioned oven dry, add 2% sodium phosphate trimer, 1% calcium stearate, 4% soybean oil, 2% jade powder and N-(β-aminoethyl of 0.8%)-γ-aminopropyltrimethoxysilane, speed lapping 8min, dries, and crosses 300 mesh sieves.

The preparation method of high hot green tensile strength molding sand, comprises the following steps:

(1), by river sand, forsterite, hectorite, rice bran co-grinding, after mistake 250 mesh sieves, with tricalcium aluminate, land plaster, steel fibre, composite powder, be dry mixed 2min;

(2) add water, hydroxypropyl methyl cellulose ether, guar gum, triethanolamine, tetraethylene-glycol dimethylacrylate, wet mixing 4min, shakes out again.

The performance test of the present embodiment molding sand is as follows:

Green compression strength (kPa): 122

Hot green tensile strength (KPa): 7.2

Gas permeability: 117

Compact rate of molding (%): 42

Shatter index (%): 81.

Claims (2)

1. one kind high hot green tensile strength molding sand, it is characterized in that, by the raw material of following weight portion, formed: river sand 80-100, forsterite 20-30, hectorite 10-15, rice bran 8-12, tricalcium aluminate 5-10, land plaster 3-6, hydroxypropyl methyl cellulose ether 1.5-2.5, steel fibre 3-5, guar gum 2-3, triethanolamine 1-2, tetraethylene-glycol dimethylacrylate 2-3, composite powder 3-6, water 4-8;

The preparation method of described composite powder is as follows: a, take perlite, fluorite and barite by weight 4-8:3-5:2-3, mix, pulverized 100-150 mesh sieve, then add water making beating and make the slurry that solid content is 50-60%, high speed ball milling 2-3h, spraying is dry; In b, the dried powder of spraying, add the coconut shell flour of 3-5%, the coal dust of the calcirm-fluoride of 2-3%, 1-2% and the yittrium oxide of 0.4-0.8%, 850-880 ℃ of calcining 30-40min, be warming up to again 1200-1250 ℃ of calcining 2-3h, shrend, then be placed in the hydrochloric acid solution that concentration is 15-20%, be heated to boiling speed lapping 20-30min, the sodium hydroxide solution regulator solution PH that is 10-15% by concentration is again to neutral, under 50-70 ℃ of bath temperature, stir 10-15min, filter, with distilled water, clean filter residue, dry; In powder after c, above-mentioned oven dry, add the sodium phosphate trimer of 2-3%, the jade powder of the soybean oil of the calcium stearate of 1-2%, 3-5%, 2-3% and N-(β-aminoethyl of 0.5-1%)-γ-aminopropyltrimethoxysilane, speed lapping 5-10min, dry, cross 200-300 mesh sieve.

2. the preparation method of high hot green tensile strength molding sand as claimed in claim 1, is characterized in that comprising the following steps:

(1), by river sand, forsterite, hectorite, rice bran co-grinding, after mistake 200-300 mesh sieve, with tricalcium aluminate, land plaster, steel fibre, composite powder, be dry mixed 2-3min;

(2) add water, hydroxypropyl methyl cellulose ether, guar gum, triethanolamine, tetraethylene-glycol dimethylacrylate, wet mixing 3-5min, shakes out again.