CN103272996A

CN103272996A - Sand sticking-resistant precoated sand

Info

Publication number: CN103272996A
Application number: CN201310131531XA
Authority: CN
Inventors: 周道虎
Original assignee: FANCHANG COUNTY HENGXIN AUTO PARTS Co Ltd
Current assignee: FANCHANG COUNTY HENGXIN AUTO PARTS Co Ltd
Priority date: 2013-04-16
Filing date: 2013-04-16
Publication date: 2013-09-04

Abstract

The invention discloses sand sticking-resistant precoated sand. The sand sticking-resistant precoated sand comprises raw sand, a binder, urotropine, calcium stearate, a silane coupling agent and an additive A. The raw sand comprises, by weight, 76 to 90 parts of river sand, 16 to 20 parts of graphite powder, 3 to 5 parts of lignin, 4 to 6 parts of asphalt and 20 to 25 parts of loess coated particles. The loess coated particles are prepared by mixing 20 to 26 weight parts of loess, 2 to 5 weight parts of sodium dihydrogen phosphate and an appropriate amount of water into block mass and carrying out calcinations and crushing. The loess coated particles have the particle sizes of 0.3 to 0.6mm. The sand sticking-resistant precoated sand has good anti-wettability, low roughness and high temperature resistance and is not sticked to a casing easily.

Description

Anti-scab precoated sand

Technical field

The present invention relates to a kind of casting model powder, relate in particular to a kind of anti-scab precoated sand, specifically be applicable to the making of casting sand mold.

Background technology

Precoated sand refers to preceding molding sand or the core sand that is covered with one deck hard resin film at sand grain surface of moulding.Two kinds of coating techniques of cold process and Re Fa are arranged: cold process with resin dissolves, and adds methenamine with ethanol in the mulling process, make the two be coated on sand grain surface, and the ethanol volatilization gets precoated sand; Hot method is preheating to uniform temperature to sand, adds resin and makes its fusion, stirs to make resin-coating at sand grain surface, adds the methenamine aqueous solution and lubricant, cooling, broken, sieve precoated sand.Be used for steel-casting, ironcasting.Intensity height, gas forming amount are low because precoated sand has, production casting dimension accuracy height, any surface finish, be convenient to advantage such as preservation, use increasingly extensive in recent years.

Precoated sand of the prior art exists that hear resistance is relatively poor, roughness defective and problem big, easily scab on foundry goods.

Summary of the invention

The objective of the invention is to overcome that the hear resistance that exists in the prior art is relatively poor, roughness defective and problem big, easily scab on foundry goods, provide that a kind of resistance to water soak is better, high temperature resistant, roughness is less, be difficult for the precoated sand of scab on foundry goods.

For realizing above purpose, technical scheme of the present invention is:

Anti-scab precoated sand, comprise roughing sand, binding agent, methenamine, calcium stearate, silane coupler and additive A, in weight portion, described roughing sand is by 76-90 part river sand, 16-20 part graphite powder, 3-5 part lignin, 4-6 part pitch, 20-25 part loess coated particle thing mixes to be formed, described loess coated particle thing be by 20-26 part loess and 2-5 part biphosphate receive and suitable quantity of water mix wet agglomerating after, obtain through calcining, after pulverizing, loess coated particle thing granularity is at 0.3-0.6mm; Described bonding agent with 8-10 part phenolic resins, 4-6 part alumine who knows, 3-5 part boric acid, 4-6 part polypropylene chopped strand, 3-5 part syrup and 12-14 part 40-45% phosphate solution mixed pulp obtain; Described additive A is to handle 1-2 hour by 4-6 part greasy filth, 2-4 part pulverized limestone, 3-5 part dextrin, 0.2-0.4 part feldspar in powder, the mixing of 6-9 part water are burnt down to forge for 300-350 ℃, burning is forged product and 4-5 part montmorillonite powder, 1-2 part E-12 epoxy resin, 2-4 part waterglass mixing granulation, obtains additive A after the oven dry;

Its preparation method is as follows: earlier 100 parts of roughing sand are put in the blade mixer, after being heated to 140-150 ℃, in roughing sand, put into described 8-10 part bonding agent mixed grind time 44-48S again, when the roughing sand temperature is reduced to 95-100 ℃, add 8-10 part methenamine, add 5-8 part calcium stearate, 0.5-0.7 part aluminum nitride powder, 0.2-0.3 part manganese dioxide, 0.5-1.0 part silane coupler and 10-12 part additive A mixed grind 45-49S behind the mixed grind 10-15S, when treating that roughing sand is down to below 80 ℃, broken, screening obtains precoated sand.

Described roughing sand is by 82 parts of river sand, 18 parts of graphite powders, 4 parts of lignin, 5 parts of pitches, 20 parts of loess coated particle things mix to be formed, described loess coated particle thing be by 23 parts of loess and 4 parts of biphosphates receive and suitable quantity of water mix wet agglomerating after, obtain after calcining, pulverizing, loess coated particle thing granularity is at 0.4mm.

Described additive A is to forge processing by 5 parts of greasy filth, 3 parts of pulverized limestones, 4 parts of dextrin, 0.3 part of feldspar in powder, 7 parts of water are mixed to burn, burning is forged product and 4 parts of montmorillonite powders, 1 part of E-12 epoxy resin, 3 parts of waterglass mixing granulations, roasting is 4 hours again, sintering temperature control obtains additive A at 460 ℃ after the pulverizing.

Compared with prior art, beneficial effect of the present invention is:

1, because a kind of precoated sand of the present invention comprises roughing sand, binding agent, curing agent and coupling agent, the consumption of various components and additive A and the granularity of roughing sand are the 100-150 order, the granularity of roughing sand emphasizes to help to improve intensity and the hear resistance of precoated sand, and the emphasizing of hardener dose helps to reduce the roughness of the sand mold that precoated sand makes up.Therefore not only hear resistance is better in the present invention, and roughness is less.

2, constituent and the weight portion ratio thereof owing to the roughing sand in a kind of precoated sand of the present invention is: roughing sand is by 58 parts of carbon sands, 45 parts of magnesia, 8 parts of diatomite, loess coated particle thing is formed, not only can improve the hear resistance of roughing sand, can also strengthen its gas permeability, thereby improve hear resistance and the gas permeability of precoated sand, gas permeability is conducive to avoid scab on the foundry goods, and, the constituent of binding agent and the design of weight portion ratio thereof are conducive to raw-material even configuration in the precoated sand, also are conducive to avoid scab on the foundry goods.Therefore gas permeability of the present invention is better, can avoid scab on foundry goods.

3, this precoated sand also has the raising rate of delaying 3-5S except the performance with conventional precoated sand, suppresses the performance of nitrogen gas generation, can effectively reduce foundry goods and produce nitrogen pore, improves the yield rate of iron casting greatly.

The specific embodiment

Anti-scab precoated sand, comprise roughing sand, binding agent, methenamine, calcium stearate, silane coupler and additive A, in weight portion, described roughing sand is by 82 parts of river sand, 18 parts of graphite powders, 4 parts of lignin, 5 parts of pitches, 25 parts of loess coated particle things mix to be formed, described loess coated particle thing be by 23 parts of loess and 4 parts of biphosphates receive and suitable quantity of water mix wet agglomerating after, obtain through calcining, after pulverizing, loess coated particle thing granularity is at 0.4mm; Described bonding agent with 8 parts of phenolic resins, 4 parts of alumines who knows, 5 parts of boric acid, 4 parts of polypropylene chopped strands, 3 parts of syrup and 12 parts of 40-45% phosphate solution mixed pulps obtain; Described additive A is by 4 parts of greasy filth, 4 parts of pulverized limestones, 5 parts of dextrin, 0.4 part of feldspar in powder, 9 parts of water mixing are burnt down to forge for 300-350 ℃ and handled 1 hour, burning is forged product and 5 parts of montmorillonite powders, 1 part of E-12 epoxy resin, 4 parts of waterglass mixing granulations, obtains additive A after the oven dry;

Its preparation method is as follows: earlier 100 parts of roughing sand are put in the blade mixer, after being heated to 140-150 ℃, in roughing sand, put into described 8 parts of bonding agent mixed grind time 44-48S again, when the roughing sand temperature is reduced to 95-100 ℃, add 8 parts of methenamines, add 8 parts of calcium stearates, 0.5 part of aluminum nitride powder, 0.3 part of manganese dioxide, 0.5 part of silane coupler and 10 parts of additive A mixed grind 45-49S behind the mixed grind 10-15S, when treating that roughing sand is down to below 80 ℃, broken, screening obtains precoated sand.

Prepare the precoated sand standard specimen as stated above, its every performance tested test result such as following table:

Normal temperature bending strength (MPa)	9.13
		Hot bending strength (MPa)	2.45
Fusing point (℃)	96
		Burning decrement (mass fraction) (%)	0.26

Claims

1. prevent the scab precoated sand, comprise roughing sand, binding agent, methenamine, calcium stearate, silane coupler and additive A, in weight portion, it is characterized in that: described roughing sand is by 76-90 part river sand, 16-20 part graphite powder, 3-5 part lignin, 4-6 part pitch, 20-25 part loess coated particle thing mixes to be formed, described loess coated particle thing be by 20-26 part loess and 2-5 part biphosphate receive and suitable quantity of water mix wet agglomerating after, obtain after calcining, pulverizing, loess coated particle thing granularity is at 0.3-0.6mm; Described bonding agent with 8-10 part phenolic resins, 4-6 part alumine who knows, 3-5 part boric acid, 4-6 part polypropylene chopped strand, 3-5 part syrup and 12-14 part 40-45% phosphate solution mixed pulp obtain; Described additive A is to handle 1-2 hour by 4-6 part greasy filth, 2-4 part pulverized limestone, 3-5 part dextrin, 0.2-0.4 part feldspar in powder, the mixing of 6-9 part water are burnt down to forge for 300-350 ℃, burning is forged product and 4-5 part montmorillonite powder, 1-2 part E-12 epoxy resin, 2-4 part waterglass mixing granulation, obtains additive A after the oven dry;

2. anti-scab precoated sand according to claim 1, it is characterized in that: described roughing sand is by 82 parts of river sand, 18 parts of graphite powders, 4 parts of lignin, 5 parts of pitches, 20 parts of loess coated particle things, described loess coated particle thing be by 23 parts of loess and 4 parts of biphosphates receive and suitable quantity of water mix wet agglomerating after, obtain after calcining, pulverizing, loess coated particle thing granularity is at 0.4mm.

3. anti-scab precoated sand according to claim 1, it is characterized in that: described additive A is to forge processing by 5 parts of greasy filth, 3 parts of pulverized limestones, 4 parts of dextrin, 0.3 part of feldspar in powder, 7 parts of water are mixed to burn, burning is forged product and 4 parts of montmorillonite powders, 1 part of E-12 epoxy resin, 3 parts of waterglass mixing granulations, roasting is 4 hours again, sintering temperature control obtains additive A at 460 ℃ after the pulverizing.