CN104801655A - High-strength foundry casting sand and preparation method thereof - Google Patents

Abstract

The invention discloses high-intensity foundry casting sand and a preparation method thereof. The high-intensity foundry casting sand comprises the following raw materials in parts by weight: 45 to 65 parts of quartz sand, 20 to 30 parts of desert sand, 15 to 20 parts of illite, 12 to 18 parts of calcium carbonate powder, 5 to 10 parts of silicon boride, 2 to 3 parts of 3-isocyanatopropyltriethoxysilane, 8 to 12 parts of modified bentonite, 5 to 10 parts of emery powder, 4 to 8 parts of shale ash, 5 to 10 parts of malthacite, 3 to 5 parts of sodium alginate, 6 to 9 parts of light calcined powder, 3 to 7 parts of carbon nanofiber, 4 to 6 parts of polyethylene imine, 2 to 3 parts of polyvinyl butyral, and a proper amount of water. Compared with the traditional casting sand, the casting sand provided by the invention is relatively high in wet compression strength and tensile strength, further is excellent in heat resistance, plasticity and air permeability, is easy for pattern drawing and modeling, has the effect of bearing various external forces and high temperature, can improve casting quality obviously, and avoids defect of air holes produced by castings.

Description

A kind of high-strength casting molding sand and preparation method thereof

Technical field

The present invention relates to a kind of high-strength casting molding sand and preparation method thereof, belong to molding sand technical field.

Background technology

Molding sand is used for the material of moulding in casting.Molding sand is generally mixed according to a certain percentage by Modeling Materials such as Foundry sand, moulding sand binder and additional things.The effect of molding sand in Foundry Production is very important, and the casting wasted product caused because of the poor quality of molding sand accounts for the 30-50% of the total waste product of foundry goods.Usually to the requirement of molding sand be: 1. there is higher intensity and heat endurance, to bear the effect of various external force and high temperature; 2. good mobility, i.e. the ability of molding sand mutual movement between sand grains under external force or Action of Gravity Field own; 3. certain plasticity, namely molding sand is out of shape under external force, can keep the ability of the shape given after external force is removed; 4. good gas permeability, namely molding sand hole is through the ability of gas; 5. high collapsibility, whether, also known as knockability, namely after casting solidification, whether molding sand easily destroys, the easy performance removed from foundry goods.Along with the development of foundry engieering, more and more high to the performance requirement such as green compression strength, tensile strength of molding sand, and the molding sand on existing market cannot meet above-mentioned requirements, therefore, is badly in need of a kind of high-strength casting molding sand of exploitation, to meet the need of market.

Summary of the invention

The object of the invention is to for the deficiencies in the prior art, a kind of high-strength casting molding sand and preparation method thereof is provided, improve green compression strength and the tensile strength of molding sand.

The technical solution used in the present invention is as follows:

A kind of high-strength casting molding sand, is made up of the raw material of following weight portion: quartz sand 45-65, Desert Sand 20-30, illite 15-20, dry powder 12-18, silicon boride 5-10, isocyanatopropyl triethoxysilane 2-3, modified alta-mud 8-12, schmigel 5-10, shale ashes 4-8, allophane 5-10, sodium alginate 3-5, light burnt powder 6-9, carbon nano-fiber 3-7, polymine 4-6, polyvinyl butyral resin 2-3, water are appropriate;

Described method for preparing modified bentonite is as follows: the slurries that solid content is 35-45% are made in the making beating that added water by bentonite, then the sodium phosphate trimer being equivalent to slurry weight weight 8-12% is added, the urea of 3-6%, the calcium lignosulfonate of 5-10%, the citric acid of 2-5%, the calcium tetraborate of 10-15%, the aluminium hydroxide of 5-10%, the ferric sulfate of polymerized silica of 8-12%, the sodium tungstate of 4-8%, be warming up to 70-80 DEG C, 4000-5000rpm speed lapping 15-20min, and then add the emulsifier op-10 being equivalent to slurry weight 2-3%, the polyvinylpyrrolidone of 5-10%, the sodium carboxymethyl starch of 4-6%, stir, be warming up to 80-90 DEG C, add the vinyl acetate being equivalent to slurry weight 40-50% again, the methacrylic acid of 10-15%, the butyl acrylate of 20-30%, the ammonium persulfate of 1-2%, stirring reaction 0.5-1h, filter, dry.

The preparation method of high-strength casting molding sand of the present invention, comprises the following steps:

(1) quartz sand, Desert Sand, silicon boride, shale ashes, light burnt powder, modified alta-mud are dry mixed 20-30s, then add the water wet mixing 2-3min accounting for mixture weight 2-3%, obtain slurry A;

(2) illite and allophane are mixed, pulverize, add dry powder, schmigel, carbon nano-fiber, sodium alginate after crossing 150-200 mesh sieve, be dry mixed 15-20s, account for the water wet mixing 1-2min of mixture weight 1-2%, obtain slurry B;

(3) slurry A is put into puddle mixer together with slurry B, then add polymine, polyvinyl butyral resin, isocyanatopropyl triethoxysilane, mixing 0.5-1h.

Beneficial effect of the present invention:

Compare with traditional sand facies, molding sand of the present invention not only has higher green compression strength and tensile strength, also there is good heat resistance, plasticity and gas permeability, easy molding and moulding, and the effect of various external force and high temperature can be born completely, significantly improve casting quality, avoid foundry goods to produce gas hole defect.

Detailed description of the invention

A kind of high-strength casting molding sand, is made up of the raw material of following weight (kg): quartz sand 55, Desert Sand 25, illite 18, dry powder 16, silicon boride 8, isocyanatopropyl triethoxysilane 2.5, modified alta-mud 10, schmigel 8, shale ashes 6, allophane 7, sodium alginate 4, light burnt powder 7, carbon nano-fiber 5, polymine 5, polyvinyl butyral resin 2.5, water are appropriate;

Described method for preparing modified bentonite is as follows: the slurries that solid content is 40% are made in the making beating that added water by bentonite, then the sodium phosphate trimer being equivalent to slurry weight weight 10% is added, the urea of 4%, the calcium lignosulfonate of 8%, the citric acid of 3%, the calcium tetraborate of 12%, the aluminium hydroxide of 7%, the ferric sulfate of polymerized silica of 10%, the sodium tungstate of 6%, be warming up to 75 DEG C, 4500rpm speed lapping 18min, and then add the emulsifier op-10 being equivalent to slurry weight 2.5%, the polyvinylpyrrolidone of 8%, the sodium carboxymethyl starch of 5%, stir, be warming up to 85 DEG C, add the vinyl acetate being equivalent to slurry weight 45% again, the methacrylic acid of 12%, the butyl acrylate of 25%, the ammonium persulfate of 1.5%, stirring reaction 40min, filter, dry.

The preparation method of high-strength casting molding sand, comprises the following steps:

(1) quartz sand, Desert Sand, silicon boride, shale ashes, light burnt powder, modified alta-mud are dry mixed 25s, then add the water wet mixing 2min accounting for mixture weight 2%, obtain slurry A;

(2) illite and allophane are mixed, pulverize, add dry powder, schmigel, carbon nano-fiber, sodium alginate after crossing 200 mesh sieves, be dry mixed 15s, account for the water wet mixing 1min of mixture weight 1.5%, obtain slurry B;

(3) slurry A is put into puddle mixer together with slurry B, then add polymine, polyvinyl butyral resin, isocyanatopropyl triethoxysilane, mixing 0.5h.

The performance test of the molding sand that above-described embodiment obtains is as follows:

Green compression strength (kPa): 56;

24h tensile strength (MPa): 0.64;

Gas permeability: 133;

Compact rate of molding (%): 51;

Shatter index (%): 85.

Claims (2)

1. a high-strength casting molding sand, it is characterized in that, be made up of the raw material of following weight portion: quartz sand 45-65, Desert Sand 20-30, illite 15-20, dry powder 12-18, silicon boride 5-10, isocyanatopropyl triethoxysilane 2-3, modified alta-mud 8-12, schmigel 5-10, shale ashes 4-8, allophane 5-10, sodium alginate 3-5, light burnt powder 6-9, carbon nano-fiber 3-7, polymine 4-6, polyvinyl butyral resin 2-3, water are appropriate;

Described method for preparing modified bentonite is as follows: the slurries that solid content is 35-45% are made in the making beating that added water by bentonite, then the sodium phosphate trimer being equivalent to slurry weight weight 8-12% is added, the urea of 3-6%, the calcium lignosulfonate of 5-10%, the citric acid of 2-5%, the calcium tetraborate of 10-15%, the aluminium hydroxide of 5-10%, the ferric sulfate of polymerized silica of 8-12%, the sodium tungstate of 4-8%, be warming up to 70-80 DEG C, 4000-5000rpm speed lapping 15-20min, and then add the emulsifier op-10 being equivalent to slurry weight 2-3%, the polyvinylpyrrolidone of 5-10%, the sodium carboxymethyl starch of 4-6%, stir, be warming up to 80-90 DEG C, add the vinyl acetate being equivalent to slurry weight 40-50% again, the methacrylic acid of 10-15%, the butyl acrylate of 20-30%, the ammonium persulfate of 1-2%, stirring reaction 0.5-1h, filter, dry.

2. the preparation method of high-strength casting molding sand according to claim 1, is characterized in that comprising the following steps:

(1) quartz sand, Desert Sand, silicon boride, shale ashes, light burnt powder, modified alta-mud are dry mixed 20-30s, then add the water wet mixing 2-3min accounting for mixture weight 2-3%, obtain slurry A;

(2) illite and allophane are mixed, pulverize, add dry powder, schmigel, carbon nano-fiber, sodium alginate after crossing 150-200 mesh sieve, be dry mixed 15-20s, account for the water wet mixing 1-2min of mixture weight 1-2%, obtain slurry B;

(3) slurry A is put into puddle mixer together with slurry B, then add polymine, polyvinyl butyral resin, isocyanatopropyl triethoxysilane, mixing 0.5-1h.