Question

Test piece for determining the RUL of a refractory brick is heated in

• A. Oxidising atmosphere
• B. Reducing atmosphere
• C. Neutral atmosphere
• D. Electric furnace

Hint:

In material testing, the name of the equipment used is often a key piece of information. For high-temperature mechanical tests on ceramics like RUL or Creep tests, an electric furnace is the standard choice for providing a controlled heating environment.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The question asks about the heating environment for a specific standard test for refractory materials called RUL, which stands for

Refractoriness Under Load. This test measures the deformation (softening and failure) of a refractory material when it is subjected to a constant load at high temperatures. The question asks where the heating is performed.

Step 2: Detailed Explanation:
The RUL test procedure involves: 1. A standard-sized cylindrical or rectangular test piece is cut from the refractory brick. 2. This test piece is placed in a furnace and a constant compressive load (typically 2 kg/cm² or 0.2 MPa) is applied to it. 3. The furnace is then heated at a controlled, constant rate (e.g., 10°C/minute). 4. The deformation (subsidence) of the test piece is continuously measured as the temperature increases. The key part of the question is the heating environment. - Options (A), (B), and (C) describe the type of

atmosphere inside the furnace (oxidizing, reducing, or neutral). While the choice of atmosphere can be important for certain research purposes as it can affect the chemical stability of the refractory, standard RUL tests are primarily concerned with the thermo-mechanical behavior. The type of atmosphere is a secondary condition. - Option (D) describes the

type of furnace used for heating. For high-temperature tests like RUL, which require precise and uniform temperature control up to very high temperatures (often > 1500°C), an

electric furnace is the standard apparatus. Electric furnaces (typically with silicon carbide or molybdenum disilicide heating elements) provide clean, controllable, and uniform heating, which is essential for the reproducibility of the test. Fuel-fired furnaces are less suitable due to difficulties in precise control and potential chemical interactions from combustion products. The question asks where the piece is heated. The most direct and correct answer describing the apparatus is the electric furnace, which is the standard equipment for this test. The other options describe the condition *within* the furnace, not the furnace itself.

Step 3: Final Answer:
The test piece for determining the RUL of a refractory brick is heated in an Electric furnace. This corresponds to option (D).