24352. Vacuum steel degassing units are lined with
24353. Pyrometric cone equivalent (PCE) value (Segar cone) of 'superduty refractories' is more than 33 which corresponds to a temperature of __________ °C.
24354. Which is the stable form of silica below 870°C ?
24355. Which one expands on heating ?
24356. Refractoriness/fusion points of 'superduty' refractories is __________ °C.
24357. Outer combustion chamber of blast furnace stove is lined with __________ bricks.
24358. Presence of MgO in alumino-silicate refractories __________ its refractoriness.
24359. Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of __________ °C.
24360. Walls, roofs & combustion chambers of annealing furnaces are made of __________ bricks.
24361. Fireclay bricks are used in the
24362. Water content in ground refractory material to be shaped into bricks by hand moulding is about __________ percent.
24363. Chromite refractories
24364. Firing temperature is minimum (1250-1400 °C) for __________ bricks.
24365. With increase in the alumina content, the refractoriness of high alumina refractories
24366. A steel member used in the furnace construction to take the thrust of the brickwork is called
24367. The ‘Blue print’ of the Indian Constitution is the?
24368. With increase in the porosity, thermal spalling resistance of fireclay brick
24369. Thoria is an expensive refractory material and is radioactive in nature. Thorium oxide is used in the manufacture of
24370. Maximum alumina content in high alumina refractory can be as high as __________ percent.
24371. Refractories are dried in the
24372. Cermets are combination of ceramic and metallic materials due to which they have high strength & resistance to high temperature. Cermets are used in the
24373. Hot metal runner in blast furnace are lined with __________ bricks.
24374. Spray test determines the __________ of refractories.
24375. The linear thermal expansion of __________ bricks upto 1000 °C is very low of the order of ≤ 0.5 percent.
24376. Fusion point of an acidic refractory material is
24377. Which is required in an insulating refractory ?
24378. 'Super refractories' are made from pure
24379. Chromite refractories are
24380. Which is the most stable crystalline form of silica at room temperature ?
24381. Silica refractories
24382. PCE value (Segar cone) of superduty refractories is more than 33, which is equivalent to a temperature of __________ °C.
24383. Which of the following is not an acidic refractory ?
24384. Insulating refractories should have
24385. Cold crushing strength of refractories depends upon its
24386. Tar bonded dolomite bricks
24387. Electrical resistor bars are made of
24388. Which is not an alumino-silicate refractory?
24389. Periclase refractory contains mainly
24390. Si percentage in silica refractories used in the walls of coke oven is about
24391. Silica bricks are attacked by basic slags at high temperature. Which of the following is not used solely as a binding material?
24392. High thermal conductivity of a refractory material is not important, when it is to be used in the
24393. Maximum safe working temperature for fireclay bricks is about __________ °C.
24394. Ferromagnetic ceramic material is not used in the
24395. Maximum water percentage in refractory mix meant for hand moulding may be as high as __________ percent.
24396. Fireclay bricks are never used in the
24397. With increasing alumina content, the fusion point of high alumina refractories
24398. Chrome magnesite bricks are used in the
24399. Machine moulding of dry mixture of refractories requires a pressure of the order of __________ kg/cm2.
24400. Except __________ , all other refractories are bad conductors of electricity (i.e, have low electrical conductivity).