UPMRC Fitter Maintainer (Civil) Paper with solution -2021

Answer.1. Increase wear resistance

Explanation:-

Hardening is a metallurgical metalworking process used to increase the hardness of a metal. To increase the wear resistance of steel, hardness should be increased by alloying or heat treatment.

Answer.3. High-speed steel

The various pipe Material are

 Cast-iron (CI) pipes:- Cast-iron pipe is used for non-pressure, sanitary, and stormwater gravity drainage service, above and below grade.

Carbon steel (CS) pipe is available in a variety of alloys. Steel pipe is manufactured either seamless (extruded) or welded. Wall thickness, known as “schedule,” ranges from schedule 5 (thinnest) to schedule 160 (thickest). Steel pipes can be joined by welding or with flanges or threaded joints.

Copper Tube is available as either hard (annealed) or drawn (soft) temper, seamless copper (CU) tubes can be joined by soldering, brazing, flared joints, and flanges.

Plastic (PL) has become the material of choice for piping systems used to convey a variety of liquids, including sewage, water, liquid fuel, and fuel gases.

Plastic materials used for pipes are either thermoplastic or thermosetting. Thermoplastics, the most commonly used pipe materials, soften when heat is applied and reharden when cool, so the pipe can be extruded or molded into shapes. Thermosetting plastics must be cured by heating or with a curing chemical to achieve permanent shapes; once shaped, they cannot be reformed.

Answer.1. Bend the pipe

Solution

Bending is a process by which metal can be deformed by plastically deforming the material and changing its shape.

Pipe bending or tube bending is a process starts with loading a Pipe into a pipe bender and clamping it into place between two dies, the clamping block, and the forming die. The Pipe is also loosely held by two other dies, the clamp die and the pressure die. The process of Pipe bending involves using mechanical force to push stock material pipe or tubing against a die, forcing the pipe or Pipe to conform to the shape of the die. Often, stock tubing is held firmly in place while the end is rotated and rolled around the die.

Answer.1. Finishing operation

Explanation:-

Lapping is a surface finishing process used for producing geometrically accurate flat, cylindrical and spherical surfaces. The removal of metal takes place by abrading action. Lapping is used for

• Removing small amounts of material from the surfaces of tools,
• Removing small defects and surface cracks left during previous operations,
• Eliminating small distortions.

Lapping is performed manually or by machine. The abrasive carry out the cutting operation. It is sprayed over the workpiece and the lapping operation is carried out by applying light pressure on the lapping tool. The material of the lapping tool is softer than the workpiece.

Answer.1. Finishing Operation

Explanation:-

Honing is a micro finishing process of removing very little material. The material is removed by means of abrasive stones. The primary purpose of honing is to remove scratches that are left after grinding.

Answer.2. X-belt

Types of Belts

Though there are many types of belts used nowadays, the following are important types of belts:

Flat belt: Flat belt is rectangular in cross-section. It is mostly used in factories and workshops, where a moderate amount of power is to be transmitted from one pulley to another. Flat-belt drives have an efficiency of about 98%. They can transmit power when the two pulleys are not more than 8 m apart.

V belt: A V belt is trapezoidal in cross-section. The groove on the rim of the pulley of a V belt drive is made deeper to take advantage of the wedge action. The belt does not touch the bottom of the groove. The V-belt drive has a better torque-transmitting capacity as compared to the flat-belt drive. Also, multiple V-belt systems, using more than one belt on a single pulley, can be used to increase the power-transmitting capacity.

Circular belt or rope: This belt is circular in cross-section. It is used with grooved pulleys. The rope is gripped on its sides as it bends down in the groove, reducing the chances of slipping. Pulleys with several grooves can also be employed to increase the power-transmitting capacity. The material used for circular belts is cotton, hemp, manila or wire.

Timing or synchronous belt: Timing belts have teeth cut on their inner surface. They require toothed wheels like gears. The teeth cut on the belt fit into the groOves on the wheel. A timing belt enables positive drive because it does not stretch or slip and transmits power at a constant velocity ratio. It is extensively used in low power applications.

Answer.4. Half belt drive

Explanation:-

Different type of belt drive

1. Open belt drive
2. Crossed belt drive
3. Quarter turn belt drive
4. Belt drive with idler pulley
5. Compound belt drive
6. Loose and fast pulley drive
7. Cone or stepped pulley drive

Answer.1. To connect two pipes with different diameter

Explanation

A coupling is a short piece of pipe whose ends are threaded on the inside (some plastics are not) used to connect straight sections of pipe. 

A reducer is a coupling for two pipe sections of different diameters.

A bushing also connects pipes, and/or fittings, of different diameters, but unlike the reducer, it is threaded on the outside of one end and on the inside of the other. This allows a larger pipe to screw onto the outside and a smaller pipe to screw into the inside of the bushing.

An elbow is an angled coupling or bushing used to change flow direction, usually by 30°, 45°, or 90°. An elbow that is an angled bushing is referred to as a “street” elbow.

Answer.4. Be 5 mm away from the work

Explanation:-

The surface of the metal to be cut should be free of grease and oil, and the heating flame held above the edge of the metal to be cut, farthest from the operator, with the nozzle at right angles to the plate. The distance of the nozzle from the plate depends on the thickness of the metal to be cut, varying from 3 to 5 mm for metal up to 50 mm thick, up to 6 mm for metal 50 to 150 mm thick. Since the oxide must be removed quickly to ensure good, clean-cut, it is always preferable to begin on the edge of the metal.

Answer.4. Belt Drive

Explanation

Belts are used for transmitting power from one shaft to another shaft. The belts may be flat belts, vee belts, etc. Other methods of transmitting power are ropes and chains. The belts and ropes are running over the pulleys. The pulleys are mounted on the two shafts.