CN104646594A - Molding sand for machine molding and preparation method thereof - Google Patents

Abstract

The invention discloses molding sand for machine molding. The molding sand is prepared from the following raw materials in parts by weight: 1-1.5 parts of black talc, 1-2 parts of crystallite biotite, 0.4-0.7 part of sodium gluconate, 15-20 parts of tridymite, 70-75 parts of cristobalite, 1-1.5 parts of molasses, 3-4 parts of sulfite pulp waste liquid, 0.8-1.2 parts of MgO, 0.1-0.3 part of polyaluminium sulfate, 4-5 parts of modified pulverized coal and 4-5 parts of water; the molding sand disclosed by the invention is good in mobility, simple in molding, applicable to machine molding and high in efficiency; during pouring, a part of tridymite is changed into cristobalite, so that cracking difficultly occurs due to high bonding strength, and the phenomena of bonding of a casting and sand are few; and the modified pulverized coal of the molding sand disclosed by the invention contains abundant volatile components and little ash content, is uniform in particles and good in liquidity, thus the brightness of the casting is increased, the defects of pores and sand inclusion are reduced by 10%-13%, and thus the collapsibility is improved.

Description

A kind of machine molding molding sand and preparation method thereof

Technical field

The present invention relates to casting field, particularly relate to a kind of machine molding molding sand and preparation method thereof.

Background technology

So-called foundry clay green-sand, refers to by roughing sand, binding agent and conforms to thing and coordinate by a certain percentage, through overmulling system, meeting the compound of modeling requirement.Because clay green-sand casting material therefor is cheap and easy to get, casting mold is simple and convenient, and all can adapt to the single-piece production of foundry goods, in batch a large amount of production, for a long time, be the basic technology of Foundry Production always.

Molding sand will have following characteristic: 1, good permeability, and after high-temperature metal liquid cast-iron pours into casting mold, producing gas must discharge smoothly in casting mold; 2, good intensity, ensures that molding sand must possess sufficiently high intensity and deformability; 3, there is good fire resistance, the integrality 4 of thermal effect at high temperature sand mold, safe and reliable, simple to operate, easy construction can be resisted, the reduction of erection time; 5, heat endurance, mobility, plasticity, compact rate of molding are good.

Existing foundry goods also exists a lot of problem, the such as phenomenon such as buckle, sand washing, drop, sweat, pore, pin hole, shrinkage cavity and porosity, loose, crackle, scab, scab, rough surface, elephant skin, shrinkage depression, this all has very large relation with molding sand, need the performance constantly improving molding sand, can improve from raw material and sand mulling craft.

In addition, coal dust is added in foundry goods green-sand, scab defect can be prevented, improve the surface smoothness of foundry goods, and burning into sand defect can be reduced, improve the defeated and dispersed function of molding sand, for wet type G. Iron Castings, effectively can also prevent subcutaneous blowhole, available circular vortex burner, air is without preheating.The size of pulverized coal particle, shape, mobility, phosphorus content, volatile matter number, ash content content determine the performance quality of foundry goods, the quality of foundry goods can be improved by the performance improving coal dust.

Summary of the invention

The object of the present invention is to provide a kind of machine molding molding sand and preparation method thereof, this sand fluidity is good, and moulding is simple, and be applicable to machine molding, efficiency is high, and adhesion strength height is not easy to crack, and it is few that sand phenomenon is stained with by foundry goods.

Technical scheme of the present invention is as follows:

A kind of machine molding molding sand, is characterized in that being made up of the raw material of following weight portion: black talc 1-1.5, crystallite biotite 1-2, Portugal gluconic acid sodium salt 0.4-0.7, tridymite 15-20, cristobalite 70-75, molasses 1-1.5, lignosulfite 3-4, MgO0.8-1.2, polyaluminium sulfate 0.1-0.3, modification coal dust 4-5, water 4-5;

Described modification coal dust is made up of the raw material of following weight portion: brown coal powder 3-3.5, ferrocene 0.05-0.08, lignosulfonate 0.02-0.04, ethanol 4-6, sodium chloride 0.1-0.2, potassium permanganate 0.2-0.3, lanthana 0.01-0.02, manganese dioxide 0.02-0.03, magnesia 0.1-0.2, nano-sized carbon 0.2-0.3; Preparation method is: add in ethanol by nano-sized carbon, lanthana, stir, add brown coal powder, and being ground to grain diameter is 10-40 μm, spraying dry in atmosphere of hydrogen, then mixes with other residual components, and sealing, to obtain final product.

The preparation method of described machine molding molding sand, is characterized in that comprising the following steps:

(1) by tridymite, cristobalite mixing, sieve, obtain the sand of particle diameter at 0.3-1.2mm, add in simpson mill, mixing 4-5 minute, then add the water of 40%, mixing 3-4 minute, obtains mixed sand;

(2) by crystallite biotite, Portugal's gluconic acid sodium salt, molasses, lignosulfite mixing, add the water of 30%, be heated to 60-70 DEG C, stir 10-15 minute, then send into three-roll grinder, grinding 20-30 minute, obtains adhesive;

(3) adhesive (2) step obtained and other residual components join in the puddle mixer in (1) step, and evenly do not add remaining water to spray shape under halt condition, wet mixing 6-8 minute, to obtain final product.

Beneficial effect of the present invention

Sand fluidity of the present invention is good, and moulding is simple, and be applicable to machine molding, efficiency is high; During casting, tridymite part becomes cristobalite, and adhesion strength height is not easy to crack, and it is few that sand phenomenon is stained with by foundry goods; Modification coal dust of the present invention, volatile matter is many, and ash content is few, uniform particles, good fluidity, adds the bright property of foundry goods, decreases the pore of 10-13%, burning into sand defect, improves collapsibility.

Detailed description of the invention

A kind of machine molding molding sand, is made up of the raw material of following weight portion (kilogram): black talc 1.3, crystallite biotite 1.5, Portugal's gluconic acid sodium salt 0.6, tridymite 18, cristobalite 73, molasses 1.3, lignosulfite 3.5, MgO1, polyaluminium sulfate 0.2, modification coal dust 4.5, water 4.5;

Described modification coal dust is made up of the raw material of following weight portion (kilogram): brown coal powder 3.3, ferrocene 0.06, lignosulfonate 0.03, ethanol 5, sodium chloride 0.1, potassium permanganate 0.2, lanthana 0.02, manganese dioxide 0.03, magnesia 0.2, nano-sized carbon 0.3; Preparation method is: add in ethanol by nano-sized carbon, lanthana, stir, add brown coal powder, and being ground to grain diameter is 10-40 μm, spraying dry in atmosphere of hydrogen, then mixes with other residual components, and sealing, to obtain final product.

The preparation method of described machine molding molding sand, comprises the following steps:

(1) by tridymite, cristobalite mixing, sieve, obtain the sand of particle diameter at 0.3-1.2mm, add in simpson mill, mix 5 minutes, then add the water of 40%, mix 3 minutes, obtain mixed sand;

(2) by crystallite biotite, Portugal's gluconic acid sodium salt, molasses, lignosulfite mixing, add the water of 30%, be heated to 65 DEG C, stir 12 minutes, then send into three-roll grinder, grind 25 minutes, obtain adhesive;

(3) adhesive (2) step obtained and other residual components join in the puddle mixer in (1) step, and evenly do not add remaining water to spray shape under halt condition, wet mixing 7 minutes, to obtain final product.

Experimental data

The testing result of the present embodiment molding sand is as follows: green compression strength 0.18MPa, normal temperature green tensile strength 23Kpa, hot green tensile strength 3.5KPa, gas forming amount 8.5ml/g, gas permeability 145, clay content 11.4%.

Claims (2)

1. a machine molding molding sand, is characterized in that being made up of the raw material of following weight portion: black talc 1-1.5, crystallite biotite 1-2, Portugal gluconic acid sodium salt 0.4-0.7, tridymite 15-20, cristobalite 70-75, molasses 1-1.5, lignosulfite 3-4, MgO0.8-1.2, polyaluminium sulfate 0.1-0.3, modification coal dust 4-5, water 4-5;

Described modification coal dust is made up of the raw material of following weight portion: brown coal powder 3-3.5, ferrocene 0.05-0.08, lignosulfonate 0.02-0.04, ethanol 4-6, sodium chloride 0.1-0.2, potassium permanganate 0.2-0.3, lanthana 0.01-0.02, manganese dioxide 0.02-0.03, magnesia 0.1-0.2, nano-sized carbon 0.2-0.3; Preparation method is: add in ethanol by nano-sized carbon, lanthana, stir, add brown coal powder, and being ground to grain diameter is 10-40 μm, spraying dry in atmosphere of hydrogen, then mixes with other residual components, and sealing, to obtain final product.

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

(1) by tridymite, cristobalite mixing, sieve, obtain the sand of particle diameter at 0.3-1.2mm, add in simpson mill, mixing 4-5 minute, then add the water of 40%, mixing 3-4 minute, obtains mixed sand;

(2) by crystallite biotite, Portugal's gluconic acid sodium salt, molasses, lignosulfite mixing, add the water of 30%, be heated to 60-70 DEG C, stir 10-15 minute, then send into three-roll grinder, grinding 20-30 minute, obtains adhesive;

(3) adhesive (2) step obtained and other residual components join in the puddle mixer in (1) step, and evenly do not add remaining water to spray shape under halt condition, wet mixing 6-8 minute, to obtain final product.