ONLY GAS WELDING, RESISTANCE WELDING AND REDIANT ENERGY WELDING INCLUDED

1. BHAGWAN MAHAVIR COLLEGE OF
ENGINEERING AND TECHNOLOGY
• SEM:4th
• SUBJECT : METAL JOINING PROCESS
SUBMITTED BY: SHAH ANIMESH N. 150063119050
PATEL RAVINDRA 150063119041
SOLANKI VISHAL 150063119058
RANA YASH 150063119046

2. JOINING PROCESSES
• In this process; two or more metals are joint to each other. Or repair/join the broken parts.
• The joints are may be permanent like welding OR may be temporary like Riveting, brazing,
soldering…
• Joining process are….
• Screw-Fastening
• Welding
• Riveting
• Brazing
• Soldering

3. GAS WELDING
• Sound weld is obtained by selecting proper size of flame, filler material and method of
moving torch
• The temperature generated during the process is 33000c
• When the metal is fused, oxygen from the atmosphere and the torch combines with
molten metal and forms oxides, results defective weld
• Fluxes are added to the welded metal to remove oxides
• Common fluxes used are made of sodium, potassium. Lithium and borax.
• Flux can be applied as paste, powder, liquid, solid coating or gas.

4. GAS WELDING EQUIPMENT
1. Gas Cylinders
2. Regulators
3. Pressure Gauges
4. Hoses
5. Welding torch
6. Check valve
7. Non return valve

5. Oxyacetylene Welding
• Flame formed by burning a mix of acetylene
(C2H2) and oxygen
• Fusion of metal is achieved by passing the inner
cone of the flame over the metal
• Oxyacetylene can also be used for cutting metals.
• CaC2 + 2H2O = Ca (OH) 2 + C2H2
C2H2+2.5O2= 2CO2+H2O(vapour)+ 306.800 cal /mol

6. ADVANTAGES:- DISADVANTAGES:-
 Simple equipment • Limited power density
• Portable • Very low welding speed
• Inexpensive • High total heat input per unit length
• Easy for maintenance and repair. • Large heat affected zone
• Severe distortion
• Not recommended for welding reactive
metals such as titanium and zirconium.

7. TYPES OF FLAMES
• Oxygen is turned on, flame immediately changes into a long white inner area (Feather)
surrounded by a transparent blue envelope is called Carburizing flame (30000c)
• Addition of little more oxygen give a bright whitish cone surrounded by the transparent
blue envelope is called Neutral flame (It has a balance of fuel gas and oxygen)
(32000c)
• Used for welding steels, aluminum, copper and cast iron
• If more oxygen is added, the cone becomes darker and more pointed, while the
envelope becomes shorter and more fierce is called Oxidizing flame
• Has the highest temperature about 34000c
• Used for welding brass and brazing operation

8. Oxyfuel Gas Welding
Fig : Three basic types of oxyacetylene flames used in oxyfuel-gas welding and cutting
operations: (a) neutral flame; (b) oxidizing flame; (c) carburizing, or reducing flame.
The gas mixture in (a) is basically equal volumes of oxygen and acetylene.

9. RESISTANCE SPOT WELDING
Top Electrode
Water
Weld
Nugget
Bottom Electrode
Resistance
Distance

10. ADVANTAGES:- DISADVANTAGES:-
• Adaptability for Automation in High-Rate
Production of Sheet Metal Assemblies
• Difficulty for maintenance or repair
• High Speed
• Adds weight and material cost to the product,
compared with a butt joint
• Economical
• Generally have higher cost than most arc
welding equipment's
• Dimensional Accuracy • Produces unfavorable line power demands
• Low tensile and fatigue strength
• Eccentric loading condition

11. Seam welding is similar to spot welding.
Equipment is very similar both in terms of welding
current production, control and pressing force.
however, differs from spot welding mainly because
of the rolling welding wheel. In most applications,
wheels on both sides of the work piece produce
the weld.
SEAM WELDING

12. Projection Welding (RPW) is a
resistance welding process which
produces coalescence of metals with the
heat obtained from resistance to
electrical current through the work parts
held together under pressure by
electrodes.
PROJECTION WELDING

13. FLASH WELDING
• In flash welding the two pieces of
metal to be joined are clamped in
dies which conduct the electric
current to the work the ends of the
two metal pieces moved together until
an arc established

14. UPSET WELDING
Is refferd to as butt welding. In this process the
metals to be welded are brought into contact under
pressure an electric current is passed through them,
and the edges are softened and fused together

15. PERCUSSION WELDING (PEW)
Percussion welding is a process in which heat is
produced from an arc that is generated by the
rapid discharge of electrical energi between the
workpieces and followed immediately by an
impacting force which weld the pieces together.

16. • When overlaying with a laser an optical
arrangement is used to focus the laser beam on
the work piece and heat it. Simultaneously hard
facing material in the form of powder is
introduced into the laser beam and melted. Due
to the narrow heat affected zone and the fast
cooling rate the heat input is low, thereby
producing an almost stress free overlay.
• The beam is focused towards the joint which
causes the materials to change from solid to
liquid state. Upon cooling it returns to a solid
state.
LASER WELDING PROCESS

17. ADVANTAGES:- DISADVANTAGES:-
• Low possibility of HAZ in the joint • Joints must be accurately positioned
• No need for filler metal • Maximum weld penetration is limited (19-
21mm)
• Reduce Latency • High reflectivity and high thermal
conductivity of materials like Aluminum
effect the weld ability of the joint
• No tool wear
• LBW is not influenced by magnetic fields