Manufacturing Technology I Set 5

Answer: carburizing flame

Explaination:
for brazing, soldering and flame hardening carburizing flame is used.

Answer: highest temperature

Explaination:
the inner cone of the flame has the highest temperature (3500°c). the outer flame has the lowest temperature.

Answer: exothermic reaction

Explaination:
the oxy acetylene gas welding is a type of exothermic reaction. 1 mole of acetylene can produce kj/mol of heat.

Answer: c2h2

Explaination:
the chemical formula of acetylene is c2h2. 1 mole of acetylene can produce kj/mol of heat.

Answer: duty cycle

Explaination:
amount of time during which the transformer will be used for welding under normal loading condition is known as the duty cycle.

Answer: open circuit voltage

Explaination:
amount of current required to generate the arc under no load condition is called short circuit current (scc).

Answer: tungsten inert gas welding

Explaination:
in tungsten inert gas welding process a non-consumable electrode is used, which is made of tungsten.

Answer: v = f(l)

Explaination:
v= a+bl, where ‘v’ is the arc voltage and ‘l’ is the length of arc in cm, a

Answer: to prevent sticking of molten metal

Explaination:
flux is used to completely

Answer: ionized

Explaination:
in plasma arc welding the gas

Answer: 0.30

Explaination:
ηtotal = ηmelting * ηheat transfer, where η denotes efficiency. there are two types of efficiencies, one is melting efficiency and another is heat transfer efficiency.

Answer: magnetic field

Explaination:
the deflection of the arc in arc blow is by a magnetic field. electric field, hydrostatic field does not affect the deflection of the arc.

Answer: 1.4

Explaination:
n = (p×total efficiency)/(q×a), where p represents power, q represents heat transfer, and a represents the cross-sectional area.

Answer: gas metal arc welding

Explaination:
gas metal arc welding uses constant voltage. tungsten inert gas welding does not use constant circuit voltage.

Answer: ceramic rings

Explaination:
in order to prevent oxidation and retain molten metal in stud welding ceramic rings are used.

Answer: size of electrode

Explaination:
the parameters control the quality of weld are size of electrode and the current that produces sufficient heat to melt the base metal and minimizes electrode splatter.

Answer: shielded metal arc welding

Explaination:
shielded metal arc welding can be a low hydrogen process or non-low hydrogen process, while submerged arc welding, gas-shielded metal arc welding, flux core arc welding are low hydrogen process.

Answer: affects the weld

Explaination:
hydrogen causes weld to crack. hence most of the welding processes are low hydrogen welding process.

Answer: cannot be used for metal sheets under 1.5mm thickness

Explaination:
the following are some

Answer: short set-up time

Explaination:
the following are some advantages of submerged arc welding: (i) high deposition rate, (ii)high quality welds with good ductility, high impact strength, good corrosion resistance, (iii)good for welding long joints(in excess of 1m), (iv)no eye protection required. some disadvantages are : (i) long set-up time, (ii)slag removal needed, (iii)used for flat or horizontal fillets only.

Answer: high deposition rate

Explaination:
gas-shielded metal arc welding is also called metal-active gas welding. the following are some advantages of gas- shielded metal arc welding : (i) suitable for metals as thin as 0.58mm, (ii)all welding positions can be used, (iii) no need to stop welding to change the consumed electrode, (iv)high deposition rates. some disadvantages are : (i)welding equipment is expensive and

Answer: structure and chemical composition of electrode

Explaination:
the structure and chemical composition of electrode wire is the differentiating factor between flux core arc welding and gas-shielded metal arc welding processes. unlike gas-shielded metal arc welding, flux core arc welding electrode wire is not solid and consists of thin-walled metal tube filled with flux.

Answer: slag removal required

Explaination:
the following are some advantages of flux core arc welding: (i)high deposition rates, (ii)can be used to groove angles as narrow as 30˚, (iii)welds in all positions can be made, (iv)has excellent weld pool control. some disadvantages are: (i) slag removal required, (ii) generates large volume of fumes and smoke.

Answer: shielded metal arc welding

Explaination:
submerged arc welding, gas- shielded metal arc welding, flux core arc welding, electro slag welding can be used when welding is done in fabrication shop. for field applications, shielded metal arc welding is preferred.

Answer: multiple electrodes may not be used

Explaination:
the following are some advantages of electro slag welding: (i) high deposition rates, (ii) multiple electrodes may be used, (iii)low distortion. some disadvantages are: (i) welds flat or vertical joints only, (ii) complicated set-up, (iii)cooling water is needed.