CN103567372A - Molding sand with high gas permeability for casting and preparation method thereof - Google Patents

Abstract

The invention discloses molding sand with high gas permeability for casting and a preparation method thereof. The molding sand with high gas permeability is prepared from the following raw materials in parts by weight: 70-80 parts of yellow sand, 20-30 parts of recycled sand, 10-15 parts of bentonite, 5-10 parts of pyrophyllite, 8-12 parts of coal cinder, 6-9 parts of roasted zeolite, 4-6 parts of rice hull ashes, 3-5 parts of composite powder, 2-3 parts of polyester fibers, 1.5-2.5 parts of cottonseed oil, 2-3 parts of dextrin, 1-2 parts of casein, 3-6 parts of limestone, and 4-8 parts of water. The molding sand disclosed by the invention is good in gas permeability, high in strength and low in gas evolution rate, has good heat resistance, mobility, plasticity and non-sticking performance, can be used for obviously improving the defects such as sand sticking, sand inclusion, sand washing and gas pores of a casting piece, and further improving the surface smoothness of the casting piece.

Description

Highly-breathable moulding sand for casting 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 highly-breathable moulding sand for casting 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.Gas permeability is one of important performance of molding sand, and the poor molding sand of gas permeability can cause foundry goods produce pore, misrun or molten metal splash occurs when cast.

Summary of the invention

The object of the present invention is to provide a kind of highly-breathable moulding sand for casting and preparation method thereof.

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

A moulding sand for casting, is comprised of the raw material of following weight portion: yellow ground 70-80, return sand 20-30, bentonite 10-15, pyrophillite 5-10, cinder 8-12, calcined zeolite 6-9, rice hull ash 4-6, composite powder 3-5, polyester fiber 2-3, cottonseed oil 1.5-2.5, dextrin 2-3, casein 1-2, quick lime 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 highly-breathable moulding sand for casting, comprises the following steps:

(1), by yellow ground, return sand, pyrophillite, cinder, calcined zeolite co-grinding, after mistake 150-200 mesh sieve, with bentonite, rice hull ash, quick lime, polyester fiber, be dry mixed 3-4min;

(2) add again water, dextrin, casein, wet mixing 2-3min, then add cottonseed oil and composite powder, and mix 4-6min, shake out.

Beneficial effect of the present invention:

Sand permeability of the present invention is good, and intensity is high, gas forming amount is low, and has good heat resistance, mobility, plasticity and stickness not, can obviously improve the defects such as foundry goods scab, burning into sand, sand washing, pore, further improves surface finish of casting.

The specific embodiment

A moulding sand for casting, is comprised of the raw material of following weight (kg): yellow ground 70, return sand 30, bentonite 12, pyrophillite 8, cinder 10, calcined zeolite 7, rice hull ash 5, composite powder 4, polyester fiber 2.5, cottonseed oil 2, dextrin 2, casein 1.5, quick lime 4, water 5;

The preparation method of described composite powder is as follows: a, take perlite, fluorite and barite by weight 5:4:3, mix, pulverized 150 mesh sieves, then adding water making beating, to make solid content be 60% slurry, high speed ball milling 2h, and spraying is dry; In b, the dried powder of spraying, add 4% coconut shell flour, 3% calcirm-fluoride, 1.5% coal dust and 0.5% yittrium oxide, 860 ℃ of calcining 35min, be warming up to 1220 ℃ of calcining 3h, shrend, is then placed in concentration and is 16% hydrochloric acid solution again, be heated to boiling speed lapping 25min, the sodium hydroxide solution regulator solution PH that is 12% by concentration again, to neutral, stirs 15min under 55 ℃ 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 0.6%)-γ-aminopropyltrimethoxysilane, speed lapping 7min, dries, and crosses 250 mesh sieves.

The preparation method of highly-breathable moulding sand for casting, comprises the following steps:

(1), by yellow ground, return sand, pyrophillite, cinder, calcined zeolite co-grinding, after mistake 150-200 mesh sieve, with bentonite, rice hull ash, quick lime, polyester fiber, be dry mixed 3-4min;

(2) add again water, dextrin, casein, wet mixing 2-3min, then add cottonseed oil and composite powder, and mix 4-6min, shake out.

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

Green compression strength (kPa): 117

Green tensile strength (KPa): 23

Gas permeability: 122

Compact rate of molding (%): 41

Shatter index (%): 83.

Claims (2)

1. a highly-breathable moulding sand for casting, it is characterized in that, by the raw material of following weight portion, formed: yellow ground 70-80, return sand 20-30, bentonite 10-15, pyrophillite 5-10, cinder 8-12, calcined zeolite 6-9, rice hull ash 4-6, composite powder 3-5, polyester fiber 2-3, cottonseed oil 1.5-2.5, dextrin 2-3, casein 1-2, quick lime 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 highly-breathable moulding sand for casting as claimed in claim 1, is characterized in that comprising the following steps:

(1), by yellow ground, return sand, pyrophillite, cinder, calcined zeolite co-grinding, after mistake 150-200 mesh sieve, with bentonite, rice hull ash, quick lime, polyester fiber, be dry mixed 3-4min;

(2) add again water, dextrin, casein, wet mixing 2-3min, then add cottonseed oil and composite powder, and mix 4-6min, shake out.