CN103100658A - Method for preparing solid-mold casting coating material for cast iron - Google Patents

Abstract

The invention discloses a method for preparing a solid-mold casting coating material for cast iron. According to the method, the solid-mold casting coating material is prepared from the following ingredients in parts by weight: 65-75 parts of quartz powder, 5-7 parts of wood ash, 10-12 parts of corundum powder, 10-12 parts of sodium bentonite, 4-6 parts of nano attapulgite, 1-2 parts of lignosulfonic acid, 2-4 parts of water glass, 2-4 parts of sodium borate, 5-7 parts of starch paste, 1.4-1.6 parts of silica sol, 1-2 parts of nanoscale ceramic powder, 0.5-0.8 part of red ferric oxide powder and 525-535 parts of water. The solid-mold casting coating material prepared by the method has excellent gas permeability and quick-drying performance in both high-temperature environments and low-temperature environments, thereby being capable of meeting the production requirements of large-sized cast parts.

Description

A kind of cast iron preparation method of full-mold casting coating

Technical field

The present invention relates to casting field, particularly a kind of cast iron preparation method of full-mold casting coating.

Background technology

The disperse system that full-mold casting coating is comprised of the material of multiple different in kind, its composition mainly comprises the compositions such as refractory material, binding agent, carrier, nano-attapulgite and special additive, needs coating good processing performance, service behaviour, quality stability are arranged and apply reappearance.Full-mold casting coating is coated in the outer surface of foamed polystyrene pattern, could the moulding cast after the coating drying.Foamed plastics is airtight, and heat distortion temperature low (approximately 70 ℃ of left and right) is poor to the affinity of water; Liquid residue after foamed plastics melted by heating, gasification is many, and gas forming amount is large, if these gases and liquid residue can not in time be discharged, foundry goods will produce the carbon defects such as gas, carburetting, Surface Wrinkle in iron.These characteristics have determined that full-mold paint should possess following performance requirement, and namely coating should have good wetability and being coated with property, good high-temperature resistant property and elevated temperature strength and good hot permeability.

The resistance to elevated temperatures of the cast paint of prior art is relatively poor, can only be fit to shorter finding of high-temperature process time (in 200kg) and produce, and can not adapt to for the production of heavy castings (in 20 tons) and small lot handwork.Have the production technology that resistant to elevated temperatures performance can be applicable to heavy castings, but its manufacturing cost is higher, and can not be applicable to manual brushing, this coating is black, easily causes the image of working environment black pollution.

Summary of the invention

For the deficiencies in the prior art, the purpose of this invention is to provide a kind of cast iron preparation method of full-mold casting coating, all have quick-drying, quick-drying, good gas permeability and drip-dry full-mold casting coating under high temperature, low temperature environment, can satisfy the heavy castings production requirement.

Technical scheme of the present invention is as follows:

A kind of cast iron is comprised of following component in weight portion: silica flour 65-75 part, trees ashes 5-7 part with the preparation method of full-mold casting coating, schmigel 10-12 part, sodium bentonite 10-12 part, nano-attapulgite 4-6 part, lignin sulfonic acid 1-2 part, waterglass 2-4 part, Boratex 2-4 part, starch paste 5-7 part, Ludox 1.4-1.6 part, nanometer scale ceramics powder 1-2 part, ferric oxide red powder 0.5-0.8 part, fluorite powder 1-2 part, vermiculite power 3-4 part, colliery powder 1-2 part; Water 55-65 part, described preparation method comprises the steps:

1) the trees ashes were soaked 3-4 hour with 12-15% sulfuric acid, the deionized water washing, soaked 2-3 hour with the 10-12% sodium hydroxide solution again, extremely neutral with the deionized water washing again, then, add the starch paste, the NaOH powder of 7-9%, the suitable quantity of water that are equivalent to its weight 5-8% to mix rear pelletizing and be broken into modification trees ash particles after 2-3 hour in calcining under 460-500 ℃;

2) the modification trees ash particles that above-mentioned steps is obtained is mixed with the water of nano-attapulgite, 1/3 weight, and stirring is heated to 150-160 ℃, is incubated 1-2 hour, stove is chilled to 55 ℃, is incubated 1-2 hour, then is heated to 100-120 ℃, be incubated 1 hour, be cooled to normal temperature with 10 ℃/hour;

3) schmigel, sodium bentonite, nanometer scale ceramics powder, starch paste, the waterglass with above-mentioned weight portion mixes with the water of 1/4 weight, and fully stirs, and then standing 40-60min, then slowly be heated to 75-85 ℃ and fully stirring;

4) with step 2) water of product, step 3) product, silica flour, Ludox, ferric oxide red powder, fluorite powder, vermiculite power, colliery powder, residuals weight adds in reactor, open reactor, mixing speed is: 110-120r/min, add other raw material in stirring downhill reaction still, the temperature that heats simultaneously reactor slowly rises to 75-85 ℃, constant temperature stirs 14-18min, grinds, gets final product.

Compared with prior art, the present invention has following beneficial effect:

1) on the basis of great many of experiments, determined composition and separately the content of aggregate, nano-attapulgite, bonding agent and the auxiliary material of coating, make the effect between above-mentioned each component reach collaborative, the combination property of coating is improved.Full-mold casting coating of the present invention had both reached high anti-stick sand ability, rigidity and the resistance to elevated temperatures of raising apperance, minimized cost again.Optimization allotment through aggregate and various additives forms high current sex change fluid, all reaches better state with foamed polystyrene pattern wetability and brushability.Facts have proved, this coating just can reach the above paint thickness of 1.7mm through 2 times brushings, and the anti-stick sand that can satisfy heavy castings requires and carry needs.

2) full-mold casting coating of the present invention has good suspension and thixotropy, also has good gas permeability and higher surface strength, and preparation technology is simple, easy to operate, abundant raw materials, production cost are low.Full mold cast(ing) surface with its production is bright and clean, without carbon defects such as elephant skin; Coating is easy to peel off, and is convenient to cleaning.

The specific embodiment

A kind of cast iron is comprised of following component in weight portion (kilogram): 75 parts of silica flours, 7 parts, trees ashes with the preparation method of full-mold casting coating, 12 parts of schmigels, 12 parts of sodium bentonites, 4 parts of nano-attapulgites, 1 part of lignin sulfonic acid, 4 parts of waterglass, 4 parts of Boratexes, 7 parts of starch pastes, 1.4 parts of Ludox, 1 part, nanometer scale ceramics powder, 0.8 part of ferric oxide red powder, 2 parts, fluorite powder, 3 parts of vermiculite powers, 1 part of colliery powder; 64 parts, water, the preparation method comprises the steps:

1) the trees ashes were soaked 3-4 hour with 12-15% sulfuric acid, the deionized water washing, soaked 2-3 hour with the 10-12% sodium hydroxide solution again, extremely neutral with the deionized water washing again, then after 2-3 hour, add the starch paste that is equivalent to its weight 8%, 9% NaOH powder, the rear pelletizing of suitable quantity of water mixing to be broken into modification trees ash particles in calcining under 460-500 ℃;

2) the modification trees ash particles that above-mentioned steps is obtained is mixed with the water of nano-attapulgite, 1/3 weight, and stirring is heated to 150-160 ℃, is incubated 1-2 hour, stove is chilled to 55 ℃, is incubated 1-2 hour, then is heated to 100-120 ℃, be incubated 1 hour, be cooled to normal temperature with 10 ℃/hour;

3) schmigel, sodium bentonite, nanometer scale ceramics powder, starch paste, the waterglass with above-mentioned weight portion mixes with the water of 1/4 weight, and fully stirs, and then standing 40-60min, then slowly be heated to 75-85 ℃ and fully stirring;

4) with step 2) water of product, step 3) product, silica flour, Ludox, ferric oxide red powder, fluorite powder, vermiculite power, colliery powder, residuals weight adds in reactor, open reactor, mixing speed is: 110-120r/min, add other raw material in stirring downhill reaction still, the temperature that heats simultaneously reactor slowly rises to 75-85 ℃, constant temperature stirs 14-18min, grinds, gets final product.

Utilize the suspensibility of coating placement after 42 hours of method preparation of the present invention greater than 94%; The shear stress of coating is limited to 19-22Pa; Be 42-45s with the apparent viscosity value that is coated with 4 viscometer determining coating, thixotroping rate 15-18%, the brushing index of coating, an amount of dropping down and a time of dropping down are respectively 5.8,0.6g and 9s.The normal temperature strength of coating is higher than 690g/mm.Through the intensity of paint coatings after 1200 ℃ of roastings higher than 490g/mm.The normal temperature gas permeability of coating is higher than 14cm ²(kPamin) ^-1, hot permeability is greater than 24cm ²(kPamin) ^-1

Claims (1)

1. a cast iron is with the preparation method of full-mold casting coating, it is characterized in that, formed by following component in weight portion: silica flour 65-75 part, trees ashes 5-7 part, schmigel 10-12 part, sodium bentonite 10-12 part, nano-attapulgite 4-6 part, lignin sulfonic acid 1-2 part, waterglass 2-4 part, Boratex 2-4 part, starch paste 5-7 part, Ludox 1.4-1.6 part, nanometer scale ceramics powder 1-2 part, ferric oxide red powder 0.5-0.8 part, fluorite powder 1-2 part, vermiculite power 3-4 part, colliery powder 1-2 part; Water 55-65 part, described preparation method comprises the steps:

1) the trees ashes were soaked 3-4 hour with 12-15% sulfuric acid, the deionized water washing, soaked 2-3 hour with the 10-12% sodium hydroxide solution again, extremely neutral with the deionized water washing again, then, add the starch paste, the NaOH powder of 7-9%, the suitable quantity of water that are equivalent to its weight 5-8% to mix rear pelletizing and be broken into modification trees ash particles after 2-3 hour in calcining under 460-500 ℃;

2) the modification trees ash particles that above-mentioned steps is obtained is mixed with the water of nano-attapulgite, 1/3 weight, and stirring is heated to 150-160 ℃, is incubated 1-2 hour, stove is chilled to 55 ℃, is incubated 1-2 hour, then is heated to 100-120 ℃, be incubated 1 hour, be cooled to normal temperature with 10 ℃/hour;

3) schmigel, sodium bentonite, nanometer scale ceramics powder, starch paste, the waterglass with above-mentioned weight portion mixes with the water of 1/4 weight, and fully stirs, and then standing 40-60min, then slowly be heated to 75-85 ℃ and fully stirring;

4) with step 2) water of product, step 3) product, silica flour, Ludox, ferric oxide red powder, fluorite powder, vermiculite power, colliery powder, residuals weight adds in reactor, open reactor, mixing speed is: 110-120r/min, add other raw material in stirring downhill reaction still, the temperature that heats simultaneously reactor slowly rises to 75-85 ℃, constant temperature stirs 14-18min, grinds, gets final product.