BS EN 993-6:2018 pdf download.Methods of test for (dense] shaped refractory products
4 Significance and use
This test is intended to be used for research, material development, manufacturing process control and design data acquisition purposes. The strength level determined by the test is calculated on the basis of linear elastic bending of a thin beam on the assumption that the material being tested is elastically homogeneous and isotropic, and shows linear (Hookean) stress-strain behaviour. The modulus of rupture may be significantly affected by a large number of factors associated with the microstructure of the material, the surface finishing procedure applied in preparation of the test pieces, the size and shape of the test piece, the orientation of the test piece during testing, the geometry and functions of the testing jig, the rate of load application and the relative humidity of the ambient atmosphere. Comparisons of the results between different determinations should accordingly not be made if one or more of these parameters differ between the two determinations. As a consequence of the brittle nature of refractories, there is usually a considerable range of results obtained from a number of nominally identical test pieces. Caution in the interpretation of test results is hence required. For many purposes, and as described in this standard, the results of the MOR test may be described in terms of a mean value and a standard deviation. Further statistical evaluation of results is required for design data acquisition, and may be desirable for other purposes. In particular, any extrapolation of modulus of rupture data to other geometries of stressing, to multiaxial stressing, to other rates of stressing or to other environments should be viewed with caution. This method places closely defined restrictions on the size and shape of the test-piece and on the function of the test apparatus in order to minimize the errors that can arise as a consequence of the test method. The method relates primarily to shaped and fired refractories. If it is to be applied to chemically bonded or tar-bonded bricks, they will usually require some form of preliminary heat treatment. This preliminary treatment is a matter of agreement between the interested parties and shall be described in the test report. This method is also applicable to unshaped refractories, more specifically on test pieces prepared according to the requirements of EN ISO 1927-5 and EN ISO 1927-6.