AS 1774.11:2015 pdf download.Refractories and refractory materials- Physical test methods Method 11: Determination of thermal expansion.
4 Contact method with cylindrical test piece
4.1 Principle
The amount of dimensional change of the cylinder test piece is continuously measured by using a contact type measurement instrument while heating at the specified rate in a heating furnace, and the linear thermal expansion rate, curve of linear thermal expansion rate, average coefficient of linear thermal expansion, and coefficient of linear thermal expansion are obtained.
4.2 Apparatus
4.2.1 Thermal expansion test apparatus
4.2.1.1 General
The circular pressure rod (1), test piece (5), and supporting rod (9) of the thermal expansion test apparatus shall be set in a heating furnace and all central axes aligned vertically. This alignment shall be maintained throughout the test as shown in Figure 1 and Figure 2. The structure of the apparatus shall be such that the thermal expansion of the test piece produced when a pressure of 0,01 MPa is applied to the direction of this central axis and the temperature is raised can be calculated from the relative change amount of the length of detecting tubes (7) and (8) contacted with the spacers (2) and (6) of the upper surface and the lower surface of the test piece. The contact force shall not change more than ±1 N.
4.2.1.2 Constitution of thermal expansion test apparatus
The apparatus shall be comprised of the following. a] Fixed pressure rod (1): The fixed pressure rod (1] shall be a cylindrical refractory material of at least 45 mm outside diameter. In the apparatus in Figure 3, the hole of concentric circle for passing through the tubes for detecting the upper and lower positions shall be provided. Care shall be taken so as not to contact with the hole of the upper lid of the heating furnace.
b) Supporting rod (9): The supporting rod (9) shall be a cylindrical refractory material of at least 45 mm outside diameter. In the apparatus in Figure 1 and Figure 2, the hole of concentric circle for passing through the tubes for detecting the upper and lower positions shall be provided.
c) Disk-type spacers (2) and (6): The disk-type spacers (2) and (6) shall be the refractory material inserted for preventing the test piece from adhering to (1) and (9) by fusion due to chemical reaction, for example a disk of at least 50 mm outside diameter and 5 mm to 10 mm thickness of the aluminosilicate refractory such as high temperature sintered mullite or alumina, or the basic refractory such as magnesia or spinel. The hole of concentric circle passing through (7) shall be provided at (6) in the apparatus shown in Figure 1 and Figure 2, and at (2) in the apparatus shown in Figure 3. Both ends of(1) and (9) shall be processed so as to be flat and in parallel position, and the spacers (2) and (6) contacted with it shall be processed to make them vertical to the central axis.
When the test piece ready to react with other refractory material, such as silica especially, is measured, the foil of platinum or platinum rhodium alloy (9) of approximately 0,2 mm in thickness may be placed between the test piece and both spacers as shown in Figure 2.
d) Tube for detecting the lower position of test piece (8): The tube for detecting the lower position of test piece (8) shall be the alumina tube of which the tip penetrates the supporting rod (9) in apparatus in Figure 1 and Figure 2 or the pressure rod (1) in the apparatus in Figure 3 and is contacted with the lower disk-type spacer adhering closely to the lower surface of the test piece, and shall be capable of moving freely so as not to make contact with the supporting rod.
e) Tube for detecting the upper position of test piece (7): The tube detecting the upper position of test piece (7) shall be the alumina tube of which the tip penetrates the supporting rod (9), the lower disk type spacer (6), and test piece (5) in the apparatus in Figure 1 and Figure 2 and is contacted with the upper disk-type spacer adhering closely to the upper surface of test piece, and shall be capable of moving freely so as not to be contacted with those. In the apparatus in Figure 3, the structures of these d) and e) are reversed.AS 1774.11 pdf download.