Few Important Questions on Welding asked in PSUs

Q1-In atomic hydrogen welding, hydrogen acts as
(a) A heating agent
(b) One of the gases to generate the flame
(c) An effective shielding gas protecting the weld
(d) A lubricant to increase the flow characteristics of weld metal

Q2-The welding process which uses a blanket of fusible granular flux is
(a) Tungsten inert gas welding
(b) Submerged arc welding
(c) Electroslag welding
(d) Thermit welding

Q3-In which of the following welding processes, flux is used in the form of granules?
(a) AC arc welding
(b) Submerged arc welding
(c) Argon arc welding
(d) DC arc welding

Q4- The welding process in which bare wire is used as electrode, granular flux is used and the process is characterized by its high speed welding, is known as:
(a) Shielded arc welding
(b) Plasma arc welding
(c) Submerged arc welding
(d) Gas metal arc welding

Q5-In MIG welding, the metal is transferred into the form of which one of the following?
(a) A fine spray of metal
(b) Molten drops
(c) Weld pool
(d) Molecules

Q6-Which one of the following welding processes uses non- consumable electrodes?
(a) TIG welding
(b) MIG welding
(c) Manual arc welding
(d) Submerged arc welding.

Q7-Which of the following arc welding processes does not use consumable electrodes?
(a) GMAW
(b) GTAW
(c) Submerged Arc Welding
(d) None of these

Q8-Following gases are used in tungsten inert gas welding [ISRO-09]
(a) CO2 and H2
(b) Argon and neon
(c) Argon and helium
(d) Helium and neon

Q9-Too high welding current in arc welding would result in
(a) Excessive spatter, under cutting along edges, irregular deposits, wasted electrodes
(b) Excessive piling up of weld metal, poor penetration, wasted electrodes
(c) Too small bead, weak weld and wasted electrodes
(d) Excessive piling up of weld metal, overlapping without penetration of edges, wasted electrodes

Q10-Pinch effect in welding is the result of
(a) Expansion of gases in the arc
(b) Electromagnetic forces
(c) Electric force
(d) Surface tension of the molten metal

Q11-Arc blow is more common in
(a) A.C. welding
(b) D.C. welding with straight polarity
(c) D.C. welding with bare electrodes
(d) A.C. welding with bare electrodes

Q12-In a linear arc welding process, the heat input per unit length is inversely proportional to
(a)Welding current
(b)Welding voltage
(c)Welding speed
(d)Duty cycle of the power source

Q13-In arc welding, d.c. reverse polarity is used to bear greater advantage in
(a) Overhead welding
(b) Flat welding of lap joints
(c) Edge welding
(d) Flat welding of butt joints

Q14-In manual arc welding, the equipment should have drooping characteristics in order to maintain
(a) Voltage constant when arc length changes
(b) Current constant when arc length changes
(c) Temperature in the are constant
(d) Weld pool red-hot

Q15-In arc welding, the arc length should be equal to
(a) 4.5 times the rod diameter
(b) 3 times the rod diameter
(c) 1.5 times the rod diameter
(d) Rod diameter

Q16-In arc welding, penetration is minimum for
(a) DCSP
(b) DCRP
(c) AC
(d) DCEN

Q17-Thick steel plate cut with oxygen normally shows signs of cracking. This tendency for cracking can be minimised by
(a) Slow speed cutting
(b) Cutting in two or more stages
(c) Preheating the plate
(d) Using oxy-acetylene flame

Q18-Oxyacetylene reducing flame is used while carrying out the welding on
(a) Mild steel                      (b) High carbon steel
(c) Grey cast iron               (d) Alloy steels

Q19-The edge of a steel plate cut by oxygen cutting will get hardened when the carbon content is
(a) Less than 0.1 percent
(b) Less than 0.3 percent
(c) More than 0.3 percent
(d) Anywhere between 0.1 to 1.0 percent

Q20-In oxy-acetylene gas welding, for complete combustion, the volume of oxygen required per unit of acetylene is
(a) 1
(b) 1.5
(c) 2
(d) 2.5

Q21-By which one of the following methods gray cast iron is usually welded?
(a) TIG welding                  (b) MIG welding
(c) Gas welding                  (d) Arc welding

Q22-The temperature of a carburising flame in gas welding is that of a neutral or an oxidising flame.
(a) Lower than
(b) Higher than
(c) Equal to
(d) Unrelated to

Q23-In Oxyacetylene gas welding, temperature at the inner cone of the flame is around
(a) 3500°C
(b) 3200°C
(c) 2900°C
(d) 2550°C

Q24-The ratio of acetylene to oxygen is approximately………. for a neutral flames used in gas welding.
(a) 1 : 1
(b) 1 : 2
(c) 1 : 3
(d) 1.5 : 1

Q25-The correct sequence of the given materials in ascending order of their weldability is
(a) MS, copper, cast iron, aluminium
(b) Cast iron, MS, aluminium copper
(c) Copper, cast iron, MS, aluminium
(d) Aluminium, copper, cast iron, MS

Q26- The major difficulty during welding of aluminium is due to its
(a) high tendency of oxidation
(b) high thermal conductivity
(c) low melting point
(d) low density