21. In brazing process, the liquid metal fills the gap by which one of the following means?
22. Match the following:
Process
Characteristics
P. Ultarasonic welding
1. Most commonly used process
Q. Plasma arc welding
2. Use of explosives
R. Thermit welding
3. Highest temperature
S. Shielded metal arc welding
4. Solid state process
5. Use of chemical energy
| Process | Characteristics |
| P. Ultarasonic welding | 1. Most commonly used process |
| Q. Plasma arc welding | 2. Use of explosives |
| R. Thermit welding | 3. Highest temperature |
| S. Shielded metal arc welding | 4. Solid state process |
| 5. Use of chemical energy |
23. Which of the following is not a solid state metal joining technique?
24. Match the following:
Group 1
Group 2
P. Thermit welding
1. Globular metal transfer
Q. Arc welding
2. Mechanical energy converted to heat energy
R. Welding in solid state
3. Exothermic process
S. Friction welding
4. Diffusion bonding
| Group 1 | Group 2 |
| P. Thermit welding | 1. Globular metal transfer |
| Q. Arc welding | 2. Mechanical energy converted to heat energy |
| R. Welding in solid state | 3. Exothermic process |
| S. Friction welding | 4. Diffusion bonding |
25. Which one of the following carbon equivalent in steel is considered good for weldability?
26. Match the welding processes in Group 1 with the principal mechanism in Group 2.
Group 1
Group 2
P. Seam welding
1. Ionisation and plasma
Q. Explosive welding
2. Exothermic reaction
R. Gas welding
3. Interfacial deformation
S. TIG welding
4. Interfacial resistance heating
5. Interfacial diffusion of atoms
| Group 1 | Group 2 |
| P. Seam welding | 1. Ionisation and plasma |
| Q. Explosive welding | 2. Exothermic reaction |
| R. Gas welding | 3. Interfacial deformation |
| S. TIG welding | 4. Interfacial resistance heating |
| 5. Interfacial diffusion of atoms |