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

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

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.

GAS WELDING EQUIPMENT

1. Gas Cylinders

2. Regulators

3. Pressure Gauges

4. Hoses

5. Welding torch

6. Check valve

7. Non return valve

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

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.

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

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.

RESISTANCE SPOT WELDINGTop Electrode

Water

WeldNugget

Bottom Electrode

Resistance

Dis

tanc

e

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

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

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

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

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

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.

• 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

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

THANK YOU