CN1152758C - Slag-trapping covering agent for casting and its pre-treating process - Google Patents

Abstract

The present invention relates to a slag collection covering agent for casting and preprocessing technology thereof. The slag collection covering agent is characterized in that crude pearlite, quartz stone raw ores and calcium fluoride raw ores are sorted, crushed and sieved, and ores with the particle size of 40 to 70 meshes are used; the slag collection covering agent is prepared by mixing 3 to 20% of quartz sands, 3 to 18% of calcium fluoride and pearl sands as the rest; mix material is baked for 5 to 60 minutes at the temperature of 200 to 400 DEG C; 0 to 5% of cryolite and 0 to 10% of borax are added in the mix material, and are uniformly mixed. The slag collection covering agent and the preprocessing technology have the advantages of good puffing characteristic, wide adaptive temperature range, easy raking and difficult breaking of a puffing slag collecting layer, and no bag hanging on the liquid molten iron or molten steel surfaces, and can be used in furnace front bags or induction electric furnaces.

Description

A kind of pretreating process of slag-trapping covering agent for casting

Technical field

The invention belongs to collection slag in the bag of cast iron, cast steel stokehold, skim and liquid level collection slag, skim used a kind of slag-trapping covering agent and pretreating process thereof in the stove when covering and heat insulating and electric induction furnace melting cast iron, cast steel.

Technical background

At China's casting industry, the slag-trapping covering agent that uses in the bag of stokehold mainly contains two big classes: the one, and rice-straw ash; The 2nd, perlite.Collect slag in electric induction furnace, skim then is all need not with perlite or what.The rice-straw ash wide material sources, low price, but contaminated environment, to worsen working condition be its fatal shortcoming.Thereby its use amount continues to descend.The charge is small for perlite, and working condition is better during use, but also have many problems: to responsive to temperature, expanded sometimes bad when molten iron temperature fluctuates when expanded, unpuffed perlite has the danger that causes the foundry goods slag inclusion when cast; Expanded collection slag blanket viscosity is not enough, and is easily broken when skimming, cause skim unclean or difficult; Expanded collection slag blanket is serious to the casting ladle wall built-up.In recent years many people have done many modification work to perlite, as allocating a certain amount of glass slag into or allocate a certain amount of rice-straw ash etc. in perlite.Though have certain effect to improving perlitic effect, its effect is still very limited, and the introducing of glass slag or rice-straw ash has brought some new problems again.

Summary of the invention

The objective of the invention is at existing the problems referred to above in the use of perlite slag-trapping covering agent, provide a kind of and have good expanded feature, adaptive temperature wide ranges at liquid molten iron or molten steel surface, expanded collection slag blanket is easily taken off and it is broken to be difficult for, not satchel, be applicable in the bag of stokehold or the new slag-trapping covering agent in the electric induction furnace stove, and for making it reach above-mentioned purpose to its pretreating process that carries out.

Said slag-trapping covering agent for casting of the present invention and pretreating process thereof are:

Choose crude pearlite, quartz raw ore, fluorite raw ore, through select materials, crushing and screening, get the ore in sand form of 20～150 order granularities.

Press quartz sand 3～20%, fluorite 3～18%, all the other proportioning mixing for pearl sand.

Compound carried out 200～400 ℃, 5～60 minutes baking.

In above-mentioned material, allocate ice crystal 0～5%, borax 0～10%, mixing again into.

The present invention has compared more performance with existing perlite slag-trapping covering agent and modified product thereof.

1. expanded feature is good.Because perlite has been carried out The pre-heat treatment, make it can reach maximum expanded multiple when expanded being heated, thereby make the collection slag blanket that better collection slag, heat insulation effect be arranged;

2. expanded collection slag blanket is difficult for broken.The adding of quartz sand has increased the viscosity and the intensity of collection slag blanket, makes the collection slag blanket be difficult for breaking and being easy to skim when skimming, and expanded heat-insulation layer is difficult for satchel.

3. the sensitiveness to swelling temperature is low.Because the adding of fluorite, borax, make it all can be expanded smoothly in sizable temperature range, and keep expanded collection slag blanket that higher viscosity and intensity are arranged.

4. can purifying molten iron, defectives such as few bleb help slowing down.The adding of ice crystal, fluorite has changed collection slag blanket and the interfacial tension of metal bath surface and the surface tension of molten metal, helps improving the purification of collection slag effect and molten metal.

The specific embodiment

One embodiment of the present of invention are: choose high quality pearl rock raw ore, synthetic quartz sand, fluorite and be crushed to 40～70 orders; Ratio mixing in perlite 87%, quartz sand 10%, fluorite 3%.350 ℃ of bakings 30 minutes, allocate borax 2%, ice crystal 1% again into, mixing.Being used for skimming in the electric induction furnace stove collects slag, skims and covers with the stokehold bag is interior, and its effect is better than existing at present like product.

Slag-trapping covering agent for casting of the present invention and pretreating process thereof can be widely used in various cast irons, cast steel production process.Can be according to the height of the difference of castings material, molten metal temperature, be used for still wrapping in the stove additional proportion of adjusting constituent element in the inherent said ratio scope, make the slag-trapping covering agent of various special uses.

Claims (1)

1. the pretreating process of a slag-trapping covering agent for casting is characterized in that, to crude pearlite, quartz raw ore, fluorite raw ore select materials, crushing and screening, get the ore in sand form of 20～150H granularity;

Press quartz sand 3～20%, fluorite 3～18%, all the other proportioning mixing for pearl sand;

Compound carried out 200～400 ℃, 5～60 minutes baking;

In above-mentioned material, allocate ice crystal 0～5%, borax 0～10%, mixing again into.