1. INTRODUCTION TO WELDING
Mr. S.A Rizvi
Ph.D(P) Welding, IIT(BHU)
ME-Production, MIIW,MISTE,MIE
Workshop Superintendent UP
FoE&T Jamia Millia Islamia,New Delhi India
/10/14

2. What is Welding
A weld is defined by the American Welding society (AWS) as “a localized coalescence (the fusion or growing together of the grain structure of the materials being welded) of materials or nonmetals produced either by heating the materials to the required welding temperatures with or without the application of pressure, or by the application of pressure alone, and with or without the use of filler materials”
Welding—a joining process that produces coalescence of materials by heating them to the welding temperature, with or without the application of pressure alone, and with or without the use of filler material.

3. Classification of welding process

4. Welding classification

5. Welding Processes Oxyacetylene Welding (OAW)
Shielded Metal Arc Welding (SMAW)
Gas Metal Arc Welding (MIG/GMAW)
Gas Tungsten Arc Welding (TIG/GTAW)
Flux Cored Arc Welding (FCAW)
Resistance welding
Submerged Arc Welding (SAW)

6. Principle of Electric arc welding

7. Comparison of welding with other joining process.
Welding is a permanent joint where as riveting and bolting is a temporary joint.
Welding joint are lighter in weight as compared to riveting and bolting.
Welding joint have more tensile strength and rigid as compared to riveting and bolting.
Welding produce 100% efficient joint which is not possible by any other joining process.

8. Advantage of welding Welding is a permanent joint.
Efficiency of welding joint is 100%
Welding produce equal strength as parent metal.
Portable welding equipment is available.
A lot of similar or dissimilar metal can be join by welding.
Welding joint is stronger as base metal
Welding joint are lighter in weight.

9. Appearance of weld bead is very smooth.
Machining operation such as grinding etc can be performed very easy on welding surface.
Alteration and amendment is possible in existing structure by welding process
Cost of welding joint is very economical.

10. Limitation of welding Edge preparation is required before welding.
Ultraviolet and infrared rays produce during welding process.
Thermal stresses are produce in the weld material.
Heat treatment process is required to remove these stress.
Skill operator is need to operate the welding machine.
HAZ produce.

11. Welding joints (i) Butt joint (ii) Tee joint (iii) Lap joint
(iv) Corner joint
(v) Edge joint
(vi) Strap joint
(vii) Plug joint

12. Special jigs & fixture are required for holding a job for welding purpose
Fumes and smokes produce during welding process.
Proper lighting arrangement is required for welding process.
Proper ventilation also required.

13. Welding Positions (i) Flat position (ii) Horizontal position
(iii) Vertical position
(iv) Overhead position

14. Welding defects External Defect Internal Defect (I) Incorrect Profile
(ii) Cracks
(iii) Crater
(iv) Spatters and
(v) surface porosity
(vi) Incomplete filling groove
(vii) Distortion
(i) Below holes & Internal porosity
(ii) Cracks
(iii) Inclusions
(iv) Lack of fusion
(v) Incomplete penetration.

15. Inspection of a welding joint
Inspection before welding
Inspection during welding
Inspection after welding

16. Testing and inspection of welding joint
Testing and inspection of welding joint is very important as joint carry load of various nature in which the weld is subjected to stress of either a simple or complex character. inspection and testing are the two different things. we should confused with each other.

17. Welding inspection and testing
Welding joint can be tested by two way.
Destructive way and Non destructive way
In destructive testing welding joint may get permanent deformation. means welding object is no longer further use.
In Non destructive testing no physical change in welding structure it can be further used.

18. Testing Welding joint testing Destructive testing
Non destructive testing

19. Destructive testing Destructive testing are such as Tensile test
Compression test
Bend test
Impact test
Nick break test
Hardness test

20. Non destructive testing
Non destructive testing are such as
Florescent test
Dye penetration test
Visual inspection test
Ultrasonic test
Cycle test
X- ray test/γ-ray test Radiography Test)
Magnetic test
Eddy current test.

21. Selection of Joining Process
What determines what equipment to use for a job.
Availability equipment
Repetitiveness of the operation (how many passes)
Quality requirements (pipeline)
Location of the weld
Materials to be joined
Appearance of the finished products
Size of the parts
Time Available

22. Application of welding
Automobile industries
Building industries
Railroad industries
Pressure vessel and storage tank manufacturing
Aircraft industries
Petrochemical industries
Ship building industries
Pipe line industries.

23. Occupational Opportunities in Welding
Welders
Tack Welders
Welding Operators
Welding Helper
Welder Assemblers/welder fitters
Welding Inspection
Welding Shop Supervisor
Welding Salesperson
Welding Shop Owners
Welding Engineers

27. Related sides
Welding Technology Institute Of Australia Central  Metallurgical Research And Development Institute
Association Of Engineers And Architects In Israel
Japan Institute Of Welding
New Zealand Welding Committee
Chinese Welding Society
Singapore Welding Society
Welding Institute Of Thailand
Swedish Welding Commission
UK Section Of The IIW TWI

28. Cont. Bulgarian Welding Society www.bsz-bg.org
National Institute R & D Of Welding And Materials Testing (ISIM)
The Danish Welding Society
Nederland's Institute Voor Lastechniek
The Russian Welding Society
Welding Institute Of Yugoslavia
American Welding Society

29. Thank you