Shaped Refractories / Mullite Bricks
M-70 Mullite Bricks
M-70 is the 68-72% Al₂O₃ grade in Shanker Agencies’ mullite bricks range, rated for continuous service to 1750°C. The nearest export designation is SK 38.
Also meets SK 30, SK 32, SK 34, SK 35, SK 36, SK 37 requirements. Those are lower duties, so a lighter grade may be the more economical choice.
M-70 technical specification
Typical values for M-70 mullite bricks. Test methods vary by property and product family, so confirm the applicable standard against the manufacturer datasheet before specifying.
| Property | M-70 |
|---|---|
| Al₂O₃ content | 68-72% |
| Apparent porosity | 16-20% |
| Cold crushing strength | 70 MPa |
| Refractoriness (PCE) | SK 37 |
| Max service temperature | 1750°C |
Grade designations and equivalents
How M-70 is referenced across Indian and export naming conventions.
| SAPL grade code | M-70 |
| Indian trade names | 70% alumina |
| Export SK equivalentNearest SK step, minimum 70% Al₂O₃ | SK 38 |
| Also meetsExceeds these requirements, a lower grade may suit those duties | SK 30, SK 32, SK 34, SK 35, SK 36, SK 37 |
| Alumina content | 68-72% Al₂O₃ |
| Measured refractoriness (PCE)This brick’s own cone value, not its SK trade grade | SK 37 |
| Max service temperature | 1750°C |
Reading an SK code correctly. SK (Seger Kegel) is a cone designation, and each step carries an accepted minimum Al₂O₃ content in trade practice. The dependable way to match an SK enquiry to a grade is that minimum alumina figure, which is how the equivalence above is derived. Note that a brick’s measured PCE and its SK trade grade are two different numbers and will not always agree. Suppliers also differ at the margins, most often around SK 34. When comparing offers, check Al₂O₃ and PCE together rather than the SK code alone.
SK series to mullite bricks reference
Standard SK steps with the SAPL grade that meets or exceeds each one. Grades are matched at or above the minimum alumina for the step, so an SK enquiry is never answered with an under-spec material.
Where M-70 is used
Full mullite bricks range
Compare M-70 against every grade SAPL stocks in this family.
Installation notes
- 1Use high-alumina or mullite mortar of matching Al₂O₃ content for jointing
- 2Maintain 2–3 mm joints; allow expansion of 6–8 mm per metre
- 3Controlled dry-out: 25°C/hr to 110°C, hold, then 30°C/hr to operating temperature
- 4Ideal where load-bearing creep resistance is critical (stove checkers, kiln decks)
Disclaimer: values are typical and compiled by Shanker Agencies Pvt. Ltd. from standard industry data and published manufacturer specifications. They are indicative, not a guarantee. Confirm the exact grade datasheet before specifying. For a certified datasheet or quotation, contact info@shankeragencies.com or +91 98999 57888.