1) What is the primary gas used for shielding in Plasma Arc Welding?
Argon
Oxygen
Nitrogen
Hydrogen
2 ) Which of the following factors does NOT affect the plasma arc temperature in Plasma Arc Welding?
Gas flow rate
Arc current
Shielding gas composition
Electrode material
3) Which plasma gas composition is commonly used for welding stainless steel in Plasma Arc Welding?
Argon+Hydrogen
Argon+Helium
Argon+Nitrogen
Argon+Carbon Dioxide
4) Which of the following electrode materials is commonly used for keyhole plasma welding in Plasma Arc Welding?
Tungsten
Copper
Aluminum
Carbon
5) What is the purpose of the pilot arc in Plasma Arc Welding?
To initiate the plasma arc
To preheat the workpiece
To stabilize the plasma arc
To control the arc current
6) The correct arrangement in ascending order of current modes during PAW process for different applications is:
Micro-plasma < Medium current < Keyhole
Micro-plasma > Medium current > Keyhole
Medium current < Micro-plasma < Keyhole
Micro-plasma < Keyhole < Medium current
7) How the current varies with time during PAW process?
Decrease, remains constant, increase
Decrease, increase, remains constant
Increase, decrease, remains constant
Increase, remains constant, decrease
8) Which of the following is true about Flux Cored Arc Welding (FCAW)?
It is a type of welding process that uses a flux-cored electrode
It is primarily used for thin sheet metal applications
It requires the use of shielding gas during the welding process
It produces clean and precise welds with minimal spatter
9) What is the purpose of the flux in the flux-cored electrode used in FCAW?
To provide additional alloying elements to the weld
To generate shielding gas during the welding process
To remove impurities from the base metal
To stabilize the arc and protect the molten weld pool
10) In FCAW, what is the purpose of the contact tip at the end of the welding gun?
To provide electrical insulation
To guide and direct the welding wire
To generate shielding gas
To regulate the arc voltage
11) During thermit welding, what type of reaction takes place between the fuel and the oxidizing agent?
Combustion reaction
Oxidation-reduction reaction
Exothermic reaction
Acid-base reaction
12) Mixture of Argon and Oxygen during the FCAW process results in:
Broader welds
Deep penetrated profile
Shallow penetrated profile
Both (b) and (c)
13) For welding thinner sheets using FCAW process, the contact tip to work distance (CWTD) should be:
Increased then decreased
Decreased
Increased
Remains constant
14) Thermit welding is a form of _____
Arc welding
Forge welding
Fusion welding
Gas welding
15) Which process is variant of MIG welding and uses tubular electrode containing flux in the core?
PAW
MIG welding
MAG welding
FCAW