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Conventional Castable
Preparation
First select the Aaditya Castable best suited to meet the particular service and operating condition - peak temperatures, strength required, thermal conductivity, resistance to abrasion etc. Then estimate the quantity required for the job. Next, l decide the best method of placing - pouring, trawling, vibra - compacting and make sure that the tools and equipment's are clean as possible and free form all old mortar, portland cement, lime and dust. One of the most important precaution to be taken is to store the bagged castables in a cool, dry area.
Mixing
Thoroughly mix the dry material before adding water to insure uniform distribution of ingredients. Follows waters addition instructions as given in the respective data sheets. Add the proper amount of clean, fresh water (preferably ice cooled) first in the mechanical mixer and then dump the capable for uniform mixing. At all cost avoid excess quantity of water as structural strength will be affected. Do not over mix and install the cast able within minutes of discharge from the mixer.
Firing
After the cast able is air cured for hours, heat curing may be initiated. Some moisture still remains, so the starting temperatures must be helt below the boiling point of water The generation of steam in the cast structure would destroy the strong bond and cause explosion spalling. The following heat and curing schedule is recommended.
- Heat gradually upto 110oC and hold alt this temperature for nearly 6 hours.
- Then raise temperature at the rate of 10oC per hour upto 550oC, and hold at this temperature for 6 hours
- After this the structure can be cooled or temperature increased for normal operations.
Placing
Where forms are required for constructing large areas such as walls, floors, arches, covers etc., or casting shapes use metal grease, to avoid loss of moisture form the cast concrete or adherence. Forms should be tight to prevent water leakage. Vibrating by pneumatic / electric power vibrators for 25-50 min should be used for pressing the castles which will eliminate voids and free entrapped air.
Curing
It is important that the refractory concrete be cuted properly during the 24 hour period following placement. Most castables take on a fast hard set and forms may be removed after about six hours; curing should be aided by fine spray of water of drenched wet gunnies covering the cast surfaces. Such curing will prevent evaporation of moisture form castables so that sufficient water will be present to aid complete development of the hydrated bond and assure maximum green strength Consult Aaditya Technical representative for exact firing schedule, procedures for curing and the type of anchors required for customers specific installations.
Anchors
Properly designed fixed of floating anchors. Special designs are available and are held in stock for supply. The proper choice of anchoring system for a construction is extremely important to the ease and speed of installation and to the maximum service life of the castable lining.
Conventional Castable
Brnad
Name
|
Recommended
Service
Temperature
(oC)
|
Chemical
Analysis
Al2O3
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Physical Properties
Cold Crushing
Strength |
Thermal
Properties
Dry Density
Refractoriness
|
%
|
AT
Temperature
(oC)
|
Min
(KG / CM2)
|
Min
(G / CC)
|
oC |
Firecast 35 N
|
1350
|
35
|
110
1350
|
300
250
|
2.10
|
1500
|
Firecast 40 N
|
1450
|
40
|
110
1450
|
300
400
|
2.55
|
1680
|
Firecast 50 N
|
1500
|
50
|
110
1500
|
300
300
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2.10
|
1655
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Firecast 50 S
|
1500
|
50
|
110
1500
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350
300
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2.15
|
1655
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Firecast 60 N
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1600
|
60
|
110
1500
|
350
300
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2.20
|
1700
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Firecasst 60 S
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1600
|
60
|
110
1600
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350
300
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2.30
|
1700
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Firecast 70 N
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1760
|
70
|
110
1550
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500
400
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2.80
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1800
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Firecast 70 S
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1750
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70
|
110
1550
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550
500
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2.90
|
1800
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Note:
"Al2O3 - Subject to variabtion of +/- 2%, N = Normal S = Super.
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