Converter changes target with manage of magnesian carbon brick

The tapping mouth of converter erodes besides what get high temperature molten steel outside, still suffer the effect of temperature leap, corrode damage is serious, its service life and lining brick cannot synchronous, often need to heat is repaired or change, affect smelt time. Convert etc static press shaping integral magnesium mouth of carbolic brick tapping, because be integral structure, change go to the lavatory more, and material converts character magnesian carbon brick, life gets rising substantially, but still cannot as synchronous as lining life, just change the frequency decreases just. When new step converter opens new stove, as a result of the action of high temperature, high pressure, tapping mouth appears likely rupture phenomenon, special attention wants when smelt. Watch 4 listed tapping mouth uses property of magnesian carbon brick.

The use circumstance of magnesian carbon brick reachs qualitative to material requirement:

In smelt process, because the use condition of each place mixes converter,mar a circumstance each are not identical. To obtain balanced corrode damage, departmental to the converter of different use condition, the brand of chooses magnesian carbon brick and quality are different also.

Change of temperature of place of cap of mouth, furnace is acuteness, corrode getting residue is more serious, should choose the magnesian carbon brick with heatproof shake strong sex. Two side divide trunnion outside action is being marred when sufferring blowing, the surface is enclothed without layer of protective broken bits, repair not easily, easy oxidation of the carbon in the brick.

Position of broken bits line and slaggy and long-term contact, corrode getting residue is serious, need build by laying bricks or stones is built have admirable the magnesian carbon brick of the sex that fight broken bits.

Side of feed a machine, the slag when blowing oxygen and molten steel and those who load useless steel and molten iron is direct bump and erosive. Should choose appliance to have the sex that fight broken bits intensity of strong, high temperature is tall, heatproof the magnesian carbon brick with shake good sex.

Crucible, hearth and other place photograph are lighter than eroding, can choose brick of common magnesium carbon, use a base when compound blowing technology, especially when the bottom blows the gas such as CO2, O2, mar more serious. Should choose fight oxidisability sex of good, heatproof shake intensity of good, high temperature the brick of advanced magnesium carbon with the tall, strong sex that fight broken bits.

Tapping mouth brick:

Tapping mouth suffers molten steel concussion, slag to erode, the oxidation of air and slag and temperature are acuteness of the integrated element such as change affect and mar serious. The way that improves tapping mouth quality is the magnesian carbon brick that use high grade raw material and adds special antioxidant, use etc static pressure shape with adding product send density and uniformity.

1, electric frit magnesia: MgO>97.5% , caO/SiO2>2, crystallize greatly

2, scale black lead: Scale black lead

3, bond: Heat up colophony of solid sex phenolic aldehyde

4, additive: Al pink, Si pink, B4C, Al - Mg alloy

5, additive action mechanism:
Precede over of A, additive carbon and oxygen reaction;
The product that after B, additive reacts, makes makes bulk expands, if the fill such as Al2O3, MA, SiO2 is stomatic, prevent black lead combustion.

   Concussion area uses brick of excel in magnesian carbon (add antirust agent) , high temperature of the pink that add Al is fought fold can amount to 16 ～ 20MPa, but coefficient of expansion is big, the sex that fight broken bits is reduced, easy flake.

6, manufacturing technology: Burden, shape , heat treatment

7, magnesia fine pink cannot too fine, <180 looks (0.088mm) already but, too fine MgO is easy by reductive into Mg.

Brand	MgO , %	C , %	Bulk density, G/cm 3	Apparent pore rate , %	Intensity of normal temperature compression MPa	High temperature is fought lose strength (1400 ℃ ×30min Bury carbon Bury carbon , MPa
MT-10 Magnesian carbon brick	≥80	≥10	≥3.00	≤5	≥40	≥8
MT-12 Magnesian carbon brick	≥80	≥12	≥3.00	≤4	≥40	≥12
MT-14 Magnesian carbon brick	≥75	≥14	≥2.95	≤4	≥40	≥12

Commonly used and fireproof material has converter: Pink of black lead of magnesia of frit of brick of magnesian carbon of brick of brick of MT-10 magnesian carbon, MT-12 magnesian carbon, MT-14, report, scale, Al, Si pink, B4C, Al - Mg alloy.