PRESENTATION ON

WELDING PROCESSES

GUIDED BY:- PROF. HITESH PATEL

MANUFACTURING PROCESS-2

SUBMITTED BY:HIMANSHI GUPTA(140120119057) / ME / A2PRACHI SHARMA(140120119216) / ME / A2

(2141908)

GANDHINAGAR INSTITUTE OF TECHNOLOGY

WELDING

•  Welding is a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone, and with or without the use of filler material.• Welding is used for making permanent joints.• It is used in the manufacture of automobile bodies, aircraft frames,

railway wagons, machine frames, structural works, tanks, furniture, boilers, general repair work and ship building.

TYPES OF WELDING

 PLASTIC WELDING OR PRESSURE WELDING:• The piece of metal to be joined are heated to a plastic state and forced

together by external pressure • Example: Resistance welding

FUSION WELDING OR NON-PRESSURE WELDING:• The material at the joint is heated to a molten state and allowed to

solidify • Example: Gas welding, Arc welding

CLASSIFICATION OF WELDING PROCESSES

CHARACTERISTICS OF WELDING

a) Deposition rateb) Deposition efficiencyc) Operation factord) Penetratione) Welding speedf) Heat inputg) Power density

SUBMERGED ARC WELDING

INTRODUCTION

• Submerged arc welding (SAW) is a method in which the heat required to fuse the metal is generated by an arc formed by an electric current passing between the electrode and the workpiece. • There is no visible arc and no sparks, spatter or fume. • The electrode may be a solid or cored wire or a strip. • SAW is normally a mechanised process.

WORKING

• The submerged arc welding flux feeds through the hopper tube and continuously distributes itself over the seam a short distance ahead of the welding zone.• The wire feed mechanism begins to feed the welding into the joint at

a controlled rate.• An electric arc is established as the current flows between the

electrode and the work.• The carriage is started(manually or automatically) to travel along the

seam.

SET UP

• Current: The total welding current can range between 100 and 3600 amps.• Wires in one molten pool: From 1 to 6.• Voltage: 20-50 volts. • Speed: 30-350 cm/min. • Deposition rate: 2-100 kg/hr.

ADVANTAGES

• High quality• Little risk of undercut and porosity • No spatter • Very little risk of lack of fusion due to deep and safe penetration • High deposition rate• High thermal efficiency • No radiation • High welding speeds are possible

LIMITATIONS

• Precise joint preparation required• No observation of arc and process during welding is possible • High operational effort • It can not be used for plates less than 5mm thickness • Flux is subjected to contamination and adsorption of moisture• Solidification cracking• Irregular wire feed

APPLICATIONS

This welding method can be used for:- • Fabrication of Boiler Pressure Vessel. • Railroad tank cars. • Structural shapes and cylinders. • Circular welds. • Beam Production. • Ship Building. • Circumferential welding in wind tower fabrication. • Longitudinal pipe welding.

HYPERBARIC WELDING

INTRODUCTION

•A chamber is created near the area to be welded and the welder does the job by staying inside the chamber• It produces high quality weld joints • The gas-tungsten arc welding process is used mostly for pipe

works•Gas metal arc welding is the best process for this welding

WORKING• It is carried out in chamber sealed around the structure to be welded• The chamber is filled with a gas at the prevailing pressure, to push

water back• The welder fitted with breathing mask and other protective devices on

the pipe line• Mask filled with a breathable mixture of helium and oxygen in the

habitat• The area under the floor of the habitat is open to water, so hyper baric

welding is termed as “HABITATWELDING”.

ADVANTAGES

• Better diver safety • Better quality welds • No build up of hydrogen and oxygen pockets • Allows for heat treatment before and after welding • Non destructive testing • Surface monitoring possible

DISADVANTAGES

• Requires large, complex equipment• Chamber has to be fabricated differently for different applications • Cost is very high and increases with depth • More energy requirement• Shark attack or other sealife attack• Drowning• Explosion from gas pockets

APPLICATIONS

• Offshore construction for tapping sea resources• Temporary repair work caused by ships collisions or unexpected

accidents• Salvaging vessels sunk in the sea• Repair and maintenance of ships • Construction of large ships beyond the capacity of existing docks. • Repair and maintenance of underwater pipelines.

STUD WELDING

INTRODUCTION

• Stud welding is a high-speed metal fastening process in which a metal fastener can be applied by a welding arc to another piece of metal.• Weld studs come in a variety of designs and shapes for a wide range of

applications.• A weld stud can be end-joined to a metal work piece instantaneously

for a high quality, high strength permanent bond. • The base metal and the welded fastener do not need to be the same

material. • Stud welding is less expensive than other fastening methods.

SET UP

The equipment required for stud welding is composed of the following:• A direct current Power Supply• A Controller• A Weld Gun• Cables to tie the system components and base metal togetherIn most systems, the power supply and controller are combined as one

component called the "Welder".

ARC STUD WELDING

• Arc Stud Welding is generally used to weld large diameter fasteners to rougher and thicker base metals.

CAPACITOR DISCHARGE STUD WELDING

• Capacitor Discharge Stud Welding is generally used to weld smaller diameter fasteners to thin base metals.

APPLICATIONS• Weld Studs fasteners are used in a wide variety of industries:• Aerospace• Appliances• Automotive• Construction• Electronics• Forging Process• Insulation Installation• Offshore• Petrochemical• Shipbuilding• Toys• Transportation

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