Principle of Manufacturing Engineering sheet 5

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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:


المكان: 3CC9+F27، طريق المنصورة - دمياط، القديم الشرقي، المنصورة، الدقهلية 35511، مصر

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