Welding Technology Interview Question and Answers
Welding Technology related questions and Answers for Oral , Interview , viva Examination .
1. Define welding. List out its uses.
- Welding is the process of joining similar or different metal by heating.
- Welding is used in the fabrication of automobile bodies, air craft, machine frames, boilers, ship building, railway wagons, etc.
2. What are the types of welding? Give example.
1) Plastic welding or pressure welding
Example : Electric resistance welding.
2) Fusion welding or non – pressure welding.
Example : Electric arc welding, gas welding.
3. List out the equipment needed for arc welding.
1. Welding generator(D.C)
2. Electrodeholder 8. Apron
3. Electrode 9. Chipping hammer
4. Cables 10. Wire brush
5. Earthing clamps
6. Protective shield or transformer(A.C) 7. Gloves
4. What are the types of consumable electrodes?
1. Bare electrodes: They are not coated with flux.
2. Lightly coated electrodes: A light layer of flux is coated on the electrodes.
3. Heavily coated electrodes: Flux is coated on the electrodes to a thickness of 1 mm to 3 mm.
5. Give the expansion of MIG and TIG
MIG – Metal Inert Gas welding
TIG – Tungsten Inert Gas welding
6. What are the advantages of atomic hydrogen welding?
1. High quality weld joint can be obtained.
2. Smooth and uniform weld is formed.
3. Very high heat is produced.
4. The life of tungsten electrode is more as A.C. supply is given.
7. What is plasma? List out the advantages of plasma arc welding.
Ionised gas jet is called plasma. It produces high heat and is used for joining metal together.
Advantages of plasma arc welding :
1) All metals can be welded by this method.
2) No filler rod is needed.
3) Welding speed is high.
4) Work pieces with more thickness can also be welded.
5) High quality welding joint can be obtained.
8. Write the applications of plasma arc and submerged arc welding.
- Stainless steel, carbon steel, monel metal, titanium, copper, brass, etc. can be welded by plasma arc welding method.
- Submerged arc welding is used for welding low carbon steel and alloy steel.
9. What is electro slag welding? Give its applications.
- Electro slag welding is a process of joining two thick metal plates by the heat generated when electric current is
passed through molten slag.
- Boiler plate, turbine shaft, stainless steel and carbon steel can be welded by this method.
10. What is resistance welding? List out the types of resistance welding.
- In resistance welding, the metal is heated to plastic stage due to the heat generated by the electric resistance.
- The types of resistance welding are :
1. Butt welding
2. Spot welding
3. Seam welding
4. Projection welding
11. Give the difference between upset butt welding and flash butt welding.
In upset butt welding, the metals to be welded are clamped in copper jaws so that there is a light contact at the ends of metals. In flash but welding, the metals to be welded are clamped in jaws so that there is a small air gap between the ends of metals.
12. What is spot welding? Give its applications.
- Spot welding is a type of resistance welding which is used for joining overlapping sheet metals by making weld at
- Boxes, cans, automobile frames and air conditioners can be welded by spot welding.
13. What is seam welding? List out its applications.
- Seam welding is a process of making weld continuously between two overlapping sheet metals.
- Seam welding is used for welding radiators, drums, leak proof tanks, automobile silencers, etc.
14. What is thermit? Give the applications of thermit welding.
- Thermit steel is a mixture of aluminium powder and iron oxide in the ration of 1:3.
- Thermit welding is used for joining heavy parts, rails, pipes, shafts, cables and worn out machine frames.
15. What is solid state welding? Give its types.
Solid state welding is the process of joining metals in solid state without melting them. The types of solid state welding are
1. Friction welding 3. Diffusion welding
2. Ultrasonic welding 4. Explosive welding
16. List out the applications and advantages of friction welding.
Friction welding is used for welding aero engine parts and gas turbine shafts. It is also used for welding pinions to shafts, rods to yokes, flanges to pipes, etc.
1) The initial cost is low.
2) Dissimilar metals can be welded.
3) It is a simple and fast process.
4) High quality weld can be obtained.
5) The power consumption is less.
17. List out the applications of ultrasonic welding.
1. It is used for welding metals up to 3 mm thick.
2. Thin sheets can be joined with thick sheets.
3. Electrical and electronic components can be welded.
4. Plastic components can also be joined.
5. It is used for welding in nuclear reactor and aircraft parts.
18. What are the techniques uses in diffusion welding?
1. Hot pressure technique
2. Gas pressure technique
3. Vacuum furnace technique
19. List out the advantages and disadvantages of explosive welding.
1. It is a simple and fast process.
2. The welding strength is high.
3. Large surfaces can be welded.
1. It a risky process. So high carefulness is needed.
2. High brittle metals cannot be welded.
3. It is not suitable for welding metals of low melting point
20. What is the principle involved in electron beam welding? Give its applications.
In this method, welding is done by the heat produced when the high velocity electron beams are focused on the object.
1. It is used for welding automobile and aero plane parts.
2. It is used for welding high temperature metals like tungsten, molybdenum and tantalum.
3. Pressure vessel and turbine parts can be welded.
21. What is LASER? List out the advantages of laser beam welding.
LASER means Light Amplification by Stimulated Emission of Radiation. It is a beam of light having a single wave length.
1. The temperature can be controlled easily.
2. Welding can be accurately done.
3. No distortion occurs.
4. Heat treated components can be welded without affecting its properties.
5. The weld is not affected by oxidation.
22. What is gas welding? Name the gases used in gas welding.
Gas welding is a process of joining metals by the heat of the flame formed when oxygen burns with another gas
The following gases are used to produce flame in gas welding.
1) Oxygen – acetylene
2) Oxygen – hydrogen
3) Air- acetylene
23. List out the equipment need for gas welding.
1. Gas cylinders 2. Pressure regulators 3. Pressure gauges 4. Hoses 5. Welding torch
24. What are the three types of flames in gas welding?
1) Neutral flame 2) Carburising flame 3) Oxidising flame
25. What is neutral flame? Give its application.
- The neutral flame is produced when equal quantity of oxygen and acetylene gases are used.
- Neutral flame is used for welding steel, cast iron, aluminium, copper and stainless steel.
26. When carburising flame is produced? State its applications.
- Carburising flame is produced when the quantity of acetylene is more than oxygen.
- Carburising flame is used for welding steel, alloy steels, non-ferrous metals, nickel and monel metal.
27. How oxidising flame is produced? List out its applications.
- Oxidising flame is produced when the quantity of oxygen is more than acetylene.
- Oxidising flame is used for welding brass, bronze, manganese and steel.
28. Give the applications of oxygen cutting and arc cutting.
- Oxygen cutting is used to cut and remove runner and riser from steel castings.
- Arc cutting is used for cutting cast iron, alloy steel and nonferrous metals.
29. What is hard facing? List out its applications.
Hard facing is a process of coating a hard metal powder on the surface of soft metals.
1. It is used for coating tungsten carbide and chromium carbide on the surface of cutting tool.
2. It is used in reconditioning of worn out machine parts by coating required metal on it.
3. It is used for coating hard metal in the die surface.
30. What is bronze welding? Give its applications.
- Bronze welding is an intermediate process between brazing and welding
- Bronze welding can be done in cast iron, steel, copper, bronze and brass.
31. Differentiate between soldering and brazing.
- Soldering is the process of joining two similar or dissimilar metals by using a low melting alloy called solder. Solder is an alloy of tin and lead.
- Brazing is the process of joining two similar or dissimilar metals by using a high melting alloy called spelter. Spelter is a mixture of copper and zinc alloy.
32. List out the types of brazing.
1. Torch brazing 3. Furnace brazing
2. Dip brazing 4. Induction brazing
33. What are the types of welded joints?
1. Butt joint 2. Lap joint 3. ‘T’ joint 4. Corner joint 5. Flange joint
34. What is edge preparation? Give shapes of edges.
Edge preparation is the process of making the edges to be joined to correct shape. This gives a good welded joint.
Shapes of edges :
1) Square 2) Single and double ‘V’ 3) Single and double ‘U’
35. List out the non-destructive and destructive methods for welded joints.
Non destructive testing methods :
i) Magnetic particle test ii) X-ray test iii) Ultrasonic test
Destructive testing methods :
i) Nick brake test ii) Bend test iii) Tensile test
36. What are the applications of magnetic particle test, X-ray test and ultrasonic test.
- Magnetic particle test is used to find out cracks and slag inclusions.
- X-ray test is used to fine out defects like porosity, blow holes and cavities.
- Ultrasonic test is used to find out defects like cracks, blow holes and porosity by using ultrasonic waves.
37. List out the various defects in welding.
1) Incomplete fusion 2) Slag inclusion 3) Crack 4) Undercut 3) Porosity and blow holes
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