questions Principle of Manufacturing Engineering
1) Answer all the
following questions:
1.
What
is welding? How is it classified?
Welding is a process for joining two
similar or dissimilar metals by fusion.
2.
What
are the advantages, disadvantages and applications of welding joints over other
joints?
ADVANTAGES
OF WELDING
1. Welding is more economical and is much faster process as
compared to other
2. Welding, if properly controlled results permanent joints having
strength equal or sometimes more than base metal.
3. Large number of metals and alloys both similar and dissimilar
can be joined by welding.
4. General welding equipment is not very costly.
5. Portable welding equipments can be easily made available.
6. Welding permits considerable freedom in design.
7. Welding can join welding jobs through spots, as continuous
pressure tight seams, end-to-end and in a number of other configurations.
8. Welding can also be mechanized
DISADVANTAGES OF WELDING
1. It results in
residual stresses and distortion of the workpieces.
2. Welded joint needs stress relieving and
heat treatment.
3. Welding gives out harmful radiations
(light), fumes and spatter.
4. Jigs, and fixtures may also be needed to
hold and position the parts to be welded
5.
Edges preparation of the welding jobs are required before welding
6.
Skilled welder is required for production of good welding
7. Heat during welding produces
metallurgical changes as the structure of the welded joint is not same as that
of the parent metal.
3.
Explain
the various types of joints commonly used in welding.
4.
Sketch
a gas welding set-up.
5.
Give
the advantages, limitations and applications of gas welding?
1. It results in residual stresses and
distortion of the workpieces.
2. Welded joint needs stress relieving and
heat treatment.
3. Welding gives out harmful radiations
(light), fumes and spatter.
4. Jigs, and fixtures may also be needed to
hold and position the parts to be welded
5. Edges preparation of the welding jobs are
required before welding
6. Skilled welder is required for production
of good welding
7. Heat
during welding produces metallurgical changes as the structure of the welded
joint is not same as that of the parent metal.
6.
Sketch
an oxygen cylinder. How does it differ from acetylene cylinder?
7.
Write
short notes on following with neat sketch:
1)
Types
of Welding Flames
1. Neutral welding flame (Acetylene
and oxygen in equal proportions).
2. Carburizing welding
flame or reducing (excess of acetylene).
3. Oxidizing welding flame (excess of oxygen).
2)
Friction
Welding
In this process, the heat for
welding is obtained from mechanically induced sliding motion between rubbing
surfaces of work-pieces as shown in Fig. 6.24. In friction welding, one part is
firmly held while the other (usually cylindrical) is rotated under simultaneous
application of axial pressure. As these parts are brought to rub against each
other under pressure, they get heated due to friction
3)
Welding
Defects
1. It results in residual stresses and
distortion of the workpieces.
2. Welded joint needs stress relieving and
heat treatment.
3. Welding gives out harmful radiations
(light), fumes and spatter.
4. Jigs, and fixtures may also be needed to
hold and position the parts to be welded
2) State which of the following statements is true and which is false:
1-
Welding
is a process for joining two similar or dissimilar metals by fusion. (
2-
Large
number of metals and alloys both similar and dissimilar can be joined by
welding. (
3-
Skilled
welder is not required for production of good welding. ( x
)
3) Name the basic
types of oxy-acetylene flames.
4) Name the
defects in welding joints are given in shown:
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