Answer: d [Reason:] Among the following, Barium Chloride is not a refractory sand, as it is counted under foundry fluxes, whereas all remaining sands are refractory sands.

Answer: a [Reason:] Silica sands are considered to be having the best moulding material. It has its occurrence in variety of crystalline modifications.

Answer: c [Reason:] Ganister is another name for silica sand. As, silica is obtained from carbon-ferrous sandstone, also known as dinas.

Answer: a [Reason:] Quartz gets melted completely at 1725°C. After reaching this temperature, the quartz would then start undergoing transformations.

Answer: a [Reason:] Even when the silica sand are packed as mould cavity, they show enough porosity and permeability, and hence are porous sands.

Answer: c [Reason:] It is one of the disadvantages of silica sand, that it has its thermal expansion temperature at 1063°F. At this temperature, the volume of the sand starts to increase.

Answer: d [Reason:] Conductivity, thermal expansion and size of the particle are few of the factors needed to be considered while selecting a refractory and not permeability.

Answer: a [Reason:] Silica sand has this as one of its advantages, that it can be used again and again for making moulds. This repetitive use of silica sand, makes production even more inexpensive.

Answer: a [Reason:] Silica sand has this as one of its advantages, that it is available without any difficulty in abundance. Hence, the cost of silica sand is also low.

Answer: b [Reason:] Silica sand is most freely available, without any difficulty in abundance. Hence, the cost of this sand is low.

Answer: a [Reason:] The air furnace or the reverberatory furnace, is an acid-lined reverberatory furnace. This furnace can be used for the manufacture of malleable iron and gray iron castings.

Answer: b [Reason:] In the air furnace or the reverberatory furnace, a pulverized bituminous lump coal is used as a fuel. If not a bituminous coal, oils are used for the same purpose.

Answer: a [Reason:] Reverberatory furnace is used for the production of malleable iron and gray iron castings. The minimum capacity of an air furnace or a reverberatory furnace is around 5 tons.

Answer: a

Answer: b [Reason:] The given figure is that of an air furnace or a reverberatory furnace. The question mark in the picture is depicting a skimming door.

Answer: c [Reason:] The question mark in the picture is depicting a fire bridge. This bridge is used for holding the molten metal. The given figure is that of an air furnace or a reverberatory furnace.

Answer: d [Reason:] The question mark in the picture is depicting a hearth. The given figure is that of an air furnace or a reverberatory furnace. This hearth finds its place above the fire bridge in the apparatus.

Answer: a [Reason:] The given figure is that of an air furnace or a reverberatory furnace. The question mark in the picture is depicting a firing door. Air and fuel are flown through this door only.

Answer: c [Reason:] The question mark in the picture is depicting a few bungs. These bungs insure the proper charging of the metal. The given figure is that of an air furnace or a reverberatory furnace.

Answer: a [Reason:] Malleable iron and high test gray iron castings are few such examples which can be produced using the reverberatory furnace or the air furnace.

Answer: b [Reason:] An indirect electric arc furnace cannot be used for melting zinc, but for melting steel, cast iron or copper and its alloys, this method can be used.

Answer: c [Reason:] An indirect arc furnace or a rocking furnace has its capacity ranging from a few kilograms to up to 2 tons. It is generally used for smaller melts.

Answer: a [Reason:] In the operation of indirect electric arc furnace, the liquid metal level has to be kept below the pouring sprout level. To accomplish this, the angle of rocking adjusts itself in different manners and maintains the liquid level.

Answer: a [Reason:] In a rocking furnace, the heat is first radiated from the hot refractory walls and the arc and conduction when the furnace starts rocking from the wall lining.

Answer: a [Reason:] In an indirect electric arc furnace, the rocking of furnace causes the melting to speed up, it also causes uniform composition of melt and does some damage to the refractory lining. This process does not cause overheating, instead it avoids it.

Answer: c [Reason:] Inside the furnace, before beginning the actual process, the pig iron is charged. Above this charged pig iron, the scrap is then placed.

Answer: d [Reason:] In an indirect electric arc furnace, the electrodes are made up of graphite generally. When the scrap is placed, these electrodes are brought near for the current to jump.

Answer: c [Reason:] The graphite electrode is designed in such a way that its diameter gets reduced at the middle of the electrode. This reduction in diameter causes a high amount of resistance in the electrode, hence generating large amount of heat.

Answer: a [Reason:] It is one of the advantages of the indirect electric arc furnace, that it does not essentially need a costly metal, but can operate even on low cost scrap metal.

Answer: a [Reason:] The rocking furnace operation or the indirect electric arc furnace operates without making noise. There are electrodes needed for this operation and some amount of electricity, making it costly.

Answer: a [Reason:] The concept of rotary melting furnace was first developed in Germany, and later because of its success, was adopted by the U.S.A and other countries of Europe.

Answer: b [Reason:] The rotary melting furnace is a cylindrical shell made up of steel shell. The rotary melting furnace is used for rotating or rocking purposes.

Answer: b [Reason:] The rotary melting furnace is used for rotating and rocking purposes. This furnace makes a complete rotation about itself every minute, hence the speed of rotation of a rotary melting furnace is 1 rpm.

Answer: c [Reason:] The refractory lining must be renewed, as the constant heating processes may cause it to damage. After approximately, 200 to 300 heats, the refractory lining should be renewed for a smooth operation.

Answer: c [Reason:] In this given figure of a rotary melting furnace, the question mark is depicting the refractory lining, which is just below the steel shell. This lining has to be renewed after a certain usage.

Answer: a [Reason:] The question mark is depicting the steel shell, which is the outer body of the furnace. The shape of this furnace is typically cylindrical.

Answer: b

Answer: d [Reason:] In this given figure of a rotary melting furnace, the question mark is depicting the molten metal, which is then being heated and further treated for the production of malleable cast iron.

Answer: b [Reason:] Here the question mark is depicting the burner. This burner is situated at the opening of the furnace at its mouth. The burner simply burns the fuel and air mixture for heating operations.

Answer: b [Reason:] A typical rotary melting furnace cannot have a capacity of 80 tons, the reason being, its minimum capacity to be 1 ton, and maximum capacity to be up to only 50 tons.

Answer: d [Reason:] In casting processes, there are many occasions on which a lot of material is wasted. Among the following, TIG welding, MIG welding and gas welding, are a few methods used in salvaging welding.

Answer: c [Reason:] In salvaging techniques, when a particular part has to be welded. Before the beginning of the weld, the defective part has to be prepared for it. Chipping, grinding and gouging are a few types of doing it.

Answer: b [Reason:] It is observed that, when the material which has been wasted, to be able to bring it to use, with the help of salvaging techniques, welding serves as the most appropriate operation than all others.

Answer: a [Reason:] When filler metals are considered, one has to be very careful while operating on it, as they play an important role in the weld characteristics. The thermal resistance has to be taken into account, but not as much as chemical resistance or corrosion resistance or the appearance of it.

Answer: d [Reason:] The process of soldering is very much similar to that of brazing, except for the temperature difference. In soldering process, the solder gets melted, when the temperature goes below 800°F.

Answer: c [Reason:] Caulking and impregnation are one of the techniques used for salvaging defective castings. Among the following, linseed oil, sodium silicate and synthetic resins are regularly used as impregnants, but not sodium carbide.

Answer: b [Reason:] Sodium silicate is a type of an impregnant, used for salvaging. The use of sodium silicate to immerse in the cast is termed as impregnation. The temperature at which this immersion should take place is between 175°F to 200°F.

Answer: b [Reason:] In impregnation technique of salvaging casts, the material has to be kept immersed inside the sodium silicate solution at a temperature between 175°F to 200°F, for about 2 hours to 4 hours.

Answer: a [Reason:] Salvaging techniques, use the generated waste from casting processes in useful means by performing various operations on it like, welding, brazing and so on. Welding operation for salvaging is most suited for high alloy steels and more to iron.

Answer: a [Reason:] There is some sort of preparation required to the defective parts of the metal, before it is put for welding. When non-ferrous materials are to be prepared, filling serves as an option, before it is welded. Grinding is also one of the options for preparing non-ferrous materials.