What is Welding?
Welding is joining two metals together by melting the base metal and the filler metal at a high temperature. Filler material, which is a pool of molten material, is used in the process of welding. The filler material helps establish a strong linkage between the base metals. The shielding process is used after welding to prevent the base and filler components from being oxidised. Several energies are used in weldings like gas flame, electron beams, ultrasound, LASER, and friction.
Advantages and Drawbacks of Welding
Advantages
- Welding establishes strong, durable, and permanent joint links.
- The process of welding results in an excellent finish.
- This technique produces a stronger weld than the base material when used with filler material.
- Welding can be performed at any place.
- Welding is an affordable and economical process.
- Sectors like construction, iron and steel, automobile, and several other industries have a huge demand for welding.
Drawbacks
- Welding is a difficult process; therefore, it should be performed under the safety and security guiding principles.
- Joined material through welding can’t be ripped to pieces easily.
- Welding requires skilled labour, which is hard to find, and a good electric supply.
Alloy Used for Welding
An alloy of tin and lead, which is called solder, is used for welding purposes. It has a low melting point.
- A typical modern solder consists of 0.75% copper and 99.25% tin.
- A mixture of (50-70%) tin, (30-50%) lead, antimony and copper were used in the old form of solders.
- Lead is a cheap metal, which also reduces the overall cost of the alloy. Lead is used in welding because it decreases the liquid point of an alloy.
Important Questions on Welding
1) In upset butt welding, what kind of resistance is experienced?
a) Thermal resistance
b) Air resistance
c) Electrical resistance
d) Frictional resistance
Correct Option: (c)
Explanation: In upset butt welding, the part to be welded is put in the jaws made of copper, which produces a solid contact. Current flows at this point of contact, and because of the electric resistance, this current gets transformed into heat.
2) Using the flash butt welding process, which can be easily welded among the following metals?
a) Carbon steel
b) Tin
c) Pig irons
d) Lead
Answer: d
Explanation: The welding of materials like steel and other iron alloys can be easily welded using the flash butt welding process, except for cast iron. Also, the materials like tin, lead and zinc can’t be welded using the flash butt method.
3) Which of the following materials are used in making the electrodes of spot welding?
a) Aluminium and copper
b) Tungsten and zinc
c) Chromium and zinc
d) Only aluminium
Correct Option: (a)
Explanation: In spot welding, the electrodes employed are required to hold a large quantity of thermal and electrical conductivity. Hence, they are primarily made up of copper and aluminium.
4) The metals to be welded in spot welding are connected using ________.
a) Mechanical pressure
b) Electric field
c) Magnetic field
d) Through direct interaction
Correct Option: (a)
Explanation: The metal or the alloy parts which are to be welded using the spot-welding process are heated in their zones. Mechanical pressure is applied to bring these parts in contact, causing them to connect.
5) For making rail tracks, thermit welding is used.
a) True
b) False
Correct Option: (a)
Explanation: Thermit welding is named fusion welding, which is used in the production of pipes, rail tracks etc. A superheated melt operates in thermit pressure welding.
6) What is the name of the junction between base metal and weld face?
a) Toe
b) Root
c) Foot
d) Puddle
Correct Option: (a)
Explanation: The intersection or junction of the base metal and weld face is identified as ‘toe’. The junction should be as minor in size as possible for better welding.
7) Which portion of the weld joint is melted by welding?
a) Toe
b) Root
c) Foot
d) Puddle
Correct Option: (d)
Explanation: By striking an arc on the deck surface, the “puddle” weld begins that causes the formation of a hole in the deck. Then by depositing electrode material on the beam, the welding operation continues, which allows the molten “puddle” to involve the penetrated deck.
8) What are the alloys used in the procedure of welding?
An alloy of tin and lead, called solder, is used for welding purposes. It has a low melting point.
- A typical modern solder consists of 0.75% copper and 99.25% tin.
- A mixture of (50-70%) tin, (30-50%) lead, antimony and copper were used in the old form of solders.
- Lead is a cheap metal that also reduces the alloy’s overall cost. Lead is used in welding because it decreases the liquid point of an alloy.
9) What are the advantages of welding?
Some advantages of welding are:
- Strong, durable, and permanent joint links are established by welding.
- The process of welding results in a great finish.
- This technique produces a stronger weld than the base material when used with filler material.
- Welding can be performed at any place
- Welding is an affordable and economical process
- Sectors like construction, iron and steel, automobile, and several other industries have a huge demand for welding.
10) Define Welding.
A fabrication process that uses high-temperature heat to join materials like metals is known as welding. So, basically, by melting the base metal and the filler metal at a high temperature, two metals can be joined together; this process is known as welding.
Practice Questions
1) What is filler material?
2) What do you mean by LASER?
3) List some advanced methods of welding.
4) What is magnetic pulse welding?
5) Define forge welding.
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