Investigation of the Main Factors Susceptible to Influence the Modulus of Rupture Testing Results of Refractory Materials

Veronique Lardot, Francis Cambier, Jean-Pierre Erauw, Isabella Mastroianni

Belgian Ceramic Research Centre (member of EMRA), 7000 Mons/Belgium

Revision

Volume 7, Issue 4, Pages 95 - 103

Abstract

Since the adoption of former PRE recommendations as European standards, most testing methods used for the determination of critical mechanical and physical properties of refractory products have not been thoroughly reassessed whereas in the meantime, refractory products have evolved drastically. The adequacy of current testing standards to fulfil today’s requirements of the market has become questionable as for instance, current documents lack any statement regarding the accuracy and precision that can be expected from the test methods described. This is particularly true for the test methods used for the determination of the modulus of rupture (MOR) of refractory products. Accordingly, within the framework of the European project ReStaR, ”Review and improvement of testing Standards for Refractory products”, the current EN standards for the determination of the MOR of dense shaped, insulating (EN 993-6) and monolithic (EN ISO 1927-6) refractory products have been re-evaluated. In the first stage of this project, as reported here, various factors susceptible to influence the test results have been thoroughly screened through factorial designs of experiments and subsequent analysis of variance in order to identify the most significant ones. These factors have been chosen primarily (but not only) amongst parameters already addressed by the current version of the standards. So far, only the test bar geometry has been found to affect significantly the MOR testing results. Other factors, as for instance the loading rate, have had but a minor, non-significant effect within the range investigated.

Keywords

modulus of rupture, testing standard, design of experiments, interlaboratory tests

References

[1] Brochen, E.; Quirmbach, P.; Volckaert, A.: Re-StaR – Concerted effort in the European refractory sector to consolidate and make EN testing standards future-proof. refractories WORLDFORUM 7 (2015) [3] 85–86 [2] Erauw, J.P.; et al.: Reappraisal of current standard testing methods for the determination of the modulus of rupture (MOR) of refractory products (Proceedings of UNITECR 2015) [3] Davies, D.: The statistical approach to engineering design in ceramics. Proc. Brit. Ceram. Soc. (1973) [22] 429–452

Copyright

Göller Verlag GmbH