K-278
Small, thin cross section parts where good thermal stability is required. Used for high temperature preheat applications in Equiax casting or in DS and SX applications where a Silica/Zircon composition is a better match to the casting process than an all Silica composition.
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Major Chemistry
| Name | Formula | Typical % |
|---|---|---|
| Silica | Sio2 | 74 |
| Zircon | ZrSiO4 | 24 |
| Alumina | Al2O3 | 1 |
| Other | -- | <1 |
Trace Element Analysis
| Element | Symbol | Typical ppm |
|---|---|---|
| Iron | Fe | <900 |
| Bismuth | Bi | <0.2 |
| Lead | Pb |
<1.0 |
| Silver | Ag | <10.0 |
| Antimony | Sb | <5.0 |
| Tin | Sn | <1.0 |
| Zinc | Zn |
<50.0 |
Cristobalite Content Range
| Property | Typical % |
|---|---|
| After Fire | 8.0 |
| After 30 minutes @1530°C | 35.0 |
Process Shrinkage (Mold to Fired)
| Property | Typical % |
|---|---|
| Length | 1.35 |
| Chord (width) | 1.65 |
Modulus of Rupture
| Property | Typical p.s.i. |
|---|---|
| @RT | 2000 |
| @RT after 1 hour @1530°C | 521 |
| @1150°C (heat @300C/hour to 1150°C, hold 10 minutes, break) | 3468 |
| @1457°C | 3437 |
Thermal Expansion
| Property | Typical |
|---|---|
| @1000°C (x10-6/°C) | 2.50 |
Physical Properties
| Property | Typical |
|---|---|
| Bulk Density | 1.83 g/cc |
| Apparent Density | 2.56 g/cc |
| Porosity | 28.0% |
| Absorption | 15.0% |
Core - Metal Reaction
Compatible with most nickel based, DS and SX alloys:
Leachability
- 30% boiling KOH
- 30 grams sample
- 15 minutes
- 50% leached
Creep Test
RT to 1475°C @ 300°C/hour. Hold for 1 hour. Cool at 600°C/hour. Test bar dimensions: L-6", C/W -1/2", P-1/4"
| Pressure (p.s.i.) | Deflection (inches) |
|---|---|
| 200 | 0.095 |
| 150 | 0.076 |
Disclaimer
The information and data presented herein are typical or average values and are not a guarantee of maximum or minimum values. Applications specifically suggested for material described herein are made solely for the purpose of illustration to enable the reader to make his own evaluation and are not intended as warranties, either express or implied, of fitness for these or other purposes. There is no representation that the recipient of this literature will receive updated editions as they become available.
