CN1225629C

CN1225629C - Carbide reinforced iron-base casting crucible for smelting aluminium alloy and its making process

Info

Publication number: CN1225629C
Application number: CN 01138318
Authority: CN
Inventors: 曾辉; 陈信; 王学华; 曹承忠
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Science and Engineering WUSE; Wuhan University of Technology WUT
Priority date: 2001-12-19
Filing date: 2001-12-19
Publication date: 2005-11-02
Anticipated expiration: 2021-12-19
Also published as: CN1375678A

Abstract

The present invention relates to a carbide granule reinforced iron-base casting crucible and a manufacture method for smelting aluminum alloy. Crucible materials of the present invention are carbide granule second phases distributed densely on an iron-base body, the size of carbide granules is from 0.5 mu m to 1 mu m, and gaps of the carbide granules are </=0.5 mu m. The present invention has the manufacture method of the crucible that molten steel for casting the crucible contains 1.1% to 1.4% of C, 0.8% to 2% of Cr, 0.01% to 0.1% of Ti or 0.02% to 0.2% of Nb, and 0.05% to 0.3%wt of La or/and Ce is added into the molten steel which is cast after aluminum feeding, deoxidization and deslagging. An inner layer of a casting molding sand core uses clay sand, a surface layer uses resin-bonded sand, coke is accumulated in the middle of the sand core, painting is not brushed at the surface of the sand core, and bottom filling casting is carried out. After sand removal is carried out on the crucible, the painting is used for brushing the inner surface and the outer surface, and the crucible is taken out after the crucible is maintained in a resistance furnace at the temperature of 730 to 750 DEG C for 2 to 4 hours. The aluminum molten erosiveness prevention of the crucible is 7 times higher than the aluminum molten erosiveness prevention of ordinary nodular iron, is 5 times higher than the aluminum molten erosiveness prevention of chromium 13 stainless steel, and is 5 times higher than the aluminum molten erosiveness prevention of grey cast iron.

Description

The carbide particle reinforced iron-base casting crucible and the manufacture method that are used for aluminum alloy melting

Technical field

The present invention relates to a kind of cast carbon steel crucible and manufacture method that is used for aluminum alloy melting, particularly a kind of carbide particle reinforced iron-base casting crucible and manufacture method of anti-molten aluminium alloy corrode.

Background technology

Crucible is the expendable equipment of Birmasil goods indispensability in mechanical industry, the auto industry.As the vessel of melting aluminum alloy, be used widely along with the increase of aluminium alloy castings output, for a long time cast-iron pots that adopt more, the life-span is short.Grey cast-iron is prone to volumetric expansion when at high temperature working, and causes losing efficacy; The spheroidal graphite cast-iron crucible corrodes and to form pit and lost efficacy until perforation because of the iron-based body between the globular graphite is vulnerable to aluminium liquid.People improve on material for this reason, form protective oxide film as cast iron being added Cr, Si, add Si, Al, Re raising matrix hear resistance.It is high 1.5 times than grey cast-iron that described aluminum melting crucible new material of the foundry engieering first phase in 1991---new material in research one literary composition of low-alloy cast iron can improve anti-aluminium corrode.Chinese patent 96229381 proposes to adopt casting method production to have the Z of chemical scab laminar surface _GThe 4Cr9Si2 alloy crucible, rough surface filling SiC or graphite material at viscosity sand layer adds aluminium oxide or magnesia then, i.e. " composite anticorrosive aluminum melting crucible ", the shortcoming of this method is to utilize chemical scab can cause the surface to generate the bulk scar, the cleaning difficulty, and fill complexity of carbonaceous material oxygenates operation.

Summary of the invention

The purpose of this invention is to provide and be easy to produce, the crucible cast(ing) surface is cleared up easily, inner surface of crucible coating tack is good, and anti-molten aluminium alloy ability is strong, and the crucible outer wall is the few carbide particle reinforced iron-base casting crucible and the manufacture method thereof that are used for aluminum alloy melting of oxidation peeling amount at high temperature.

The present invention seeks to realize like this, the cast carbon steel crucible that is used for aluminum alloy melting, characteristics are that dense distribution carbide particle second phase on its iron-based body, described carbide particle is of a size of 0.5 μ m～1 μ m, the gap of carbide particle≤0.5 μ m, described carbide particle second are the carbide of iron and chromium mutually.

Described crucible contains 1.1%～1.4%wt carbon.

Described crucible contains 0.8%～2%wt Cr, 0.01%～0.1%wt Ti or 0.02%～0.2%wt Nb.

Described crucible contains 0.05%～0.08%wt Ti or 0.1%～0.16%wt Nb.

The manufacture method of above-mentioned crucible, be to make in the molten steel of casting crucible to contain 1.1%～1.4%wt carbon, 0.8%～2%wt Cr, 0.01%～0.1%wt Ti or 0.02%～0.2%wt Nb, in molten steel, add 0.05%～0.3%wt Ce or/and La, aluminum deoxidation slagging-off back cast, casting mold core internal layer clay-bonded sand is piled up coke in the middle of the top layer resin sand, core, the core surface is swabbing not, bottom pouring type pouring, after the crucible sand removal with in the coating brushing, outer surface is incubated 2～4 hours in 730～750 ℃ of resistance furnaces, taking-up gets final product, and described coating is for containing weight 15% zinc oxide, the solution of 3% waterglass and 82% water.

The used resin sand of casting sand core is become to be grouped into p-methyl benzenesulfonic acid curing agent, quartz sand by nitrogen furan resin binding agent in the commercially available KJN-3 type, its composition percetage by weight is that binding agent 2%～3%, curing agent account for binding agent 30%～40%, surplus is quartz sand, and summation is weight a hundred per cent.

Ce, La add with monometallic or alloy form.

The present invention utilizes high-carbon steel to add Cr, Ti or Nb and Rare-Earth Ce or/and La forms alloy, under the effect of temperature, the crystal grain of iron and carbide particle are tiny in the metal liquid, carbide in the liquid is because alloy and rare-earth action have higher surface energy, form limpens, the crucible that cast is formed is incubated 2～4 hours in 730～750 ℃ of intervals, make carbide formation graininess in the material, particle size is 0.5 μ m～1 μ m, matrix there is invigoration effect, iron-based body space between the particle≤0.5 μ m.The carbide particle that contains alloy helps crucible to improve anti-aluminium corrode ability and the ability that has improved the oxidation of opposing crucible furnace gas.

Crucible material is highly dense carbide particle second phase that distributing on the iron-based body.Because matrix is continuous, so have certain toughness, can stand furnace charge and add fashionable impact; Because the carbide particle dense distribution has and satisfies transportation, the required intensity of lifting; Metal carbides have higher fusing point and chemical stability than metal, the existence of a large amount of granular carbides, make the material at high temperature can be all by austenitizing, the gap becomes narrow because of particle more between the carbide, and the iron-based tissue is diminished by the possibility of aluminium alloy liquid corrode between the particle as a result.Utilize formative technology, make the crucible after the cast have rough inner-surface, protective coating is easily brushed, and difficult drop-off, so this crucible has the combination property of resistance to oxidation and refractory erosion.

The casting mold core adopts resin sand and clay-bonded sand is compound makes, pile up coke in the middle of the core, be beneficial to gas discharging in the sand, adopt clay-bonded sand around the coke, resin sand is adopted on the core surface, and resin sand is big because of space between the sand grains, forms inner surface of crucible penetration when helping to pour into a mould, form no scar but coarse surface, make things convenient for the coating brushing and adhere to.Core internal layer clay-bonded sand is in order to reduce cost.

The specific embodiment

Embodiment 1

After in intermediate frequency furnace, adding the low-carbon waste steel fusing, add foundry iron again, be melted to high temperature, adjusting the molten metal carbon content is that 1.1%wt obtains the high-carbon metal liquid, adds the Cr and the 0.02%Ti of liquation weight 1%, 0.05%Ce, Ce adds with the mishmetal form, Re24.8%, Mn3.21%, Si38% (weight) in the mishmetal, aluminum deoxidation, slagging-off cast.Adopt the bottom pouring type pouring method, crucible bottom up, ingate connects the top of crucible, crucible bottom is placed rising head, and core adopts resin sand and clay-bonded sand is compound makes, and piles up coke in the middle of the core, resin sand adopts aforementioned resin sand, after the crucible sand removal after the cast, adopt acetylene---oxygen flame cutting running gate system and rising head, residual root grinder buffing.After crucible is disposed dead head; with coating (15% zinc oxide+3% waterglass+82% water wt) brushing inner surface and outer surface; insulation is 3 hours in 730～750 ℃ of resistance furnaces; impel the whole granulatings of carbide in the crucible material; metallography microscope is observed and is measured carbide particle size 0.5 μ m～1 μ m, particle gap≤0.5 μ m.The Kesternich test data of material that this example obtains see Table 1.

Embodiment 2

After in electric arc furnaces, adding the low-carbon waste steel fusing, add foundry iron again, be melted to 1520～1550 ℃, adjusting the molten metal carbon content is that 1.4%wt obtains the high-carbon metal liquid, adds the Cr and the 0.08%Nb of liquation weight 2%, 0.1%La, add with the mishmetal form, Re24.8%, Mn3.21%, Si38% in the mishmetal are undertaken by the subsequent handling of embodiment 1 then, metallography microscope is observed and is measured carbide particle size 0.5 μ m～1 μ m, carbide particle gap≤0.5 μ m.The Kesternich test data of material that this example obtains see Table 1.

As can be seen from Table 1, the anti-aluminium corrode of crucible material of the present invention is compared with common pearlitic ductile iron and has been improved 7 times, compare with 13 stainless steels and to have improved 5 times, compare with regular gray iron and to have improved 5 times, this invention can be produced by steel-casting foundry, crucible after the cast can be done heat treatment by steel-casting foundry, also can use department to finish before use by crucible.

Table 1 material that the present invention obtains and other material be Kesternich test data (φ 14 * 20 samples placed 740 ℃ of aluminium liquid 24 hours) in ZL108 liquid

The sample material	Cr ₁₃	Regular gray iron	Pearlitic ductile iron	This crucible material embodiment 1	This crucible material embodiment 2
The sample material	Cr ₁₃	Regular gray iron	Pearlitic ductile iron	This crucible material embodiment 1	This crucible material embodiment 2	Weight loss ratio %	20.95	?19.68	?28.63	?3.22	?3.04

Claims

1, a kind of cast carbon steel crucible that is used for aluminum alloy melting, it is characterized in that dense distribution carbide particle second phase on the iron-based body, described carbide particle is of a size of 0.5 μ m～1 μ m, the gap of carbide particle≤0.5 μ m, and described carbide particle second is the carbide of iron and chromium mutually.

2, crucible as claimed in claim 1 is characterized in that containing in the crucible 1.1%～1.4%wt carbon.

3, crucible as claimed in claim 1 is characterized in that containing in the crucible 0.8%～2%wt Cr, 0.01%～0.1%wt Ti or 0.02%～0.2%wt Nb.

4, the manufacture method of the described crucible of claim 1, it is characterized in that making in the molten steel of casting crucible and contain 1.1%～1.4%wt carbon, 0.8%～2%wt Cr, 0.01%～0.1%wt Ti or 0.02%～0.2%wtNb, in molten steel, add 0.05%～0.3%wt Ce or/and La, aluminum deoxidation slagging-off back cast, casting mold core internal layer clay-bonded sand is piled up coke in the middle of the top layer resin sand, core, the core surface is swabbing not, bottom pouring type pouring, after the crucible sand removal with in the coating brushing, outer surface is incubated 2～4 hours in 730～750 ℃ of resistance furnaces, taking-up gets final product, and wherein said coating is weight 15% zinc oxide, the solution of 3% waterglass and 82% water.

5, method as claimed in claim 4, it is characterized in that used resin sand is become to be grouped into p-methyl benzenesulfonic acid curing agent, quartz sand by nitrogen furan resin binding agent in the KJN-3 type, its composition percetage by weight is that binding agent accounts for 2%～3%, curing agent accounts for binding agent 30%～40%, surplus is quartz sand, and summation is weight a hundred per cent.