BS-EN-993-7 pdf free download
BS-EN-993-7 pdf free download. Methods of test for dense shaped refractory products – Part 7: Determination of modulus of rupture at elevated temperatures.
4 Principle
Test pieces taken from items (bricks) are heated to the test temperature. After being maintained at this temperature until a specified temperature distribution is reached, the test pieces are loaded at a constant rate of increase of tensile stress until failure occurs.
5 Apparatus
5.1 Loading device.
5.1.1 The loading device shall have two bearing edges to support the test piece and one for the application of the load. The three bearing edges shall be parallel to each other. For normal test pieces, the distance between the bearing edges supporting the test piece shall be 125 mm ±2 mm, with proportionate separations for other test piece lengths (see 6.2). The load bearing edge shall be placed centrally between the two supporting bearing edges to an accuracy of± 2 mm (see Figure 1). The bearing edges and test pieces shall be free from any reaction on contact at the test temperature.
5.1.2 The bearing edges shall have a length at least 5 mm greater than the breadth of the test pieces and a radius of curvature of 5 mm ± 1 mm. Since the bearing edges become flattened with use, they shall be examined periodically to ensure that their radii remain within these limits.
5.1.3 The distance between the two supporting bearing edges (see Figure 1) shall be measured at room temperature to an accuracy of ±0,5 mm.
NOTE This value is taken into account in the calculation of the modulus of rupture.
5.1.4 The loading device shall be capable of applying a load uniformly across the centre of the test piece and of increasing it at a constant rate. Means shall be provided for recording or indicating the load at failure to an accuracy of ±2 %.
5.2 Furnace.
5.2.1 The furnace shall be one of the following types:
a) batch type, in which a number of test pieces is heated to the test temperature together and tested in turn;
b) sequential type, in which the test pieces are heated to the test temperature one after another as they pass through the apparatus.
5.2.2 In either case, the furnace shall be capable of providing the temperature control and the overall heating of both the loading device and the test pieces, as required by 7.1.
5.2.3 The atmosphere in the furnace shall be air or some other specified gas, as agreed between the parties concerned in the test.5.3 Temperature measuring device. 5.3.1 The temperature of a test piece shall be measured using a calibrated thermocouple located in the proximity of the midpoint of the tensile face of the test piece. 5.3.2 The difference between the temperature measured by the thermocouple and the temperature at the midpoint of the tensile face shall first be established and shall be checked periodically in accordance with the procedure given in annex A. 5.4 Drying oven. 5.5 Cailipers, capable of measuring to an accuracy of ±0,1 mm for measuring the test piece dimensions. 5.6 Thermocouple, in accordance with EN 60584-1. 6 Test pieces 6.1 Number The number of test pieces to be tested for each item (brick) at each test temperature shall be agreed between the interested parties and shall be the same for each item; it shall be stated in the test report. 6.2 Shape and size 6.2.1 Unless otherwise agreed, the test piece shall be a rectangular bar with a cross-section of 25 mm ± 1 mm x 25 mm ± 1 mm and a length of about 150 mm. The longitudinal faces of each test piece shall be parallel to each other within a tolerance of ±0,5 mm and the sides of a cross-section of the test piece shall be parallel to each other within ±0,2 mm. Care shall be taken to ensure that the test pieces have smooth surfaces and clean edges. If other sizes of’ test piece are to be used, the dimensions shall be altered in steps of 5 mm, with a minimum of 100 mm for the length and a minimum of 10 mm for the width and for the height.BS-EN-993-7 pdf download.
