PRESENTATION NAMEMANUFACTURING PROCESSES IDIFFERENT TYPES OF WELDING

PRESENTED BY: ZAIN-UL-ABIDIN………….(01103209) HUMAYUN HASSAN.......(01103081) SHOAIB NAWAZ…………..(01103212) UMAIR ASIF…………………(01103011)

LECTURER: MUNIM SHAUKAT

WELDING

Welding is a process in which two or more parts of same or different material are joined together with the help of heat or pressure is known as welding. The joint formed is known as welded joint.

TYPES OF WELDING

(1). THERMITE WELDING (2). ELECTRON BEAM WELDING(EBW) (3). SOLID STATE WELDING (a). COLD WELDING (b). ULTRA SONIC WELDING

THERMITE WELDING

Thermite welding is an exothermic welding process that uses thermite to melt metal, which is poured between two workpieces to form a welded joint.

REACTION

The aluminium reduces the oxide of another metal, most commonly iron oxide, because aluminium is highly reactive. The maximum reachable temperature is 3090 0C. The products are aluminium oxide, free elemental iron, and a large amount of heat. The reaction is used for thermite welding, often used to join rail tracks.

Fe2O3 + 2Al → 2Fe + Al2O3

TEMPERATURE VARIATION The reaction of the Thermite-

welding is started at about 1200 0C using a special ignition powder. The maximum reachable temperature is 3090 0C that has to be reduced quickly to about 2480 0C by the addition of non reacting pellets of ferroalloy.

SLAG

At 2500 0C the aluminum would vaporize. The aluminum slag (Al2O3), that has to remain liquid to float and separate from the metal, would solidify at 2040 0C (3700 0F) and less.

LABLED DIAGRAM

APPLICATION

• Thermite welding is mainly used in repair and

welding of large forgings and castings, pipes, mill housings and heavy rail sections.

• Applications are used to repair heavy sections

• Often used to join rail tracks

• Field welding of track

ELECTRON BEAM WELDING

Electron Beam Welding (EBW) is a fusion joining process that produces a weld by impinging a beam of high energy electrons to heat the weld joint. (EBW) is done in vacuum. 

PROCESS An EBW gun functions similarly to a TV picture

tube. The major difference is that a TV picture tube continuously scans the surface of a luminescent screen using a low intensity electron beam to produce a picture. An EBW gun uses a high intensity electron beam to target a weld joint. The weld joint converts the electron beam to the heat input required to make a fusion weld.

EQUIPMENTS

• Electron gun, generating the electron beam• Working chamber, mostly evacuated to "low"

or "high" vacuum• Work-piece manipulator (positioning

mechanism)• Supply and control/monitoring electronics

FUNCTION

The electron beam is always generated in a high Although, high vacuum welding will provide maximum purity and high depth to width ratio welds.

LABLED DIAGRAM

SOLID STATE WELDING

Solid State Welding is a welding process, in which two work pieces are joined under a pressure providing an intimate contact between them and at a temperature essentially below the melting point of the parent material.

TYPES OF SOLID STATE WELDING

COLD PRESSURE WELDING

ULTRA SONIC WELDING

COLD WELDING Cold or contact welding is

a solid state welding process in which joining takes place without fusion/heating at the interface of the two parts to be welded. Unlike in the fusion-welding processes, no liquid or molten phase is present in the joint.

PRINCIPLE

Cold welding is a method for joining non-ferrous metals and their alloys without using heat, fillers or fluxes. Round wire sections, dissimilar materials and materials of different sizes can all be welded with BWE's proven cold welding technology. A cold weld is generally stronger than the parent material and has the same electrical characteristics.

DIES IN COLD WELDING

The dies play an important role in the cold weld process. Firstly, they must grip the material firmly and, therefore, the inside of the cavity is either etched with an electric pencil or, when the die is to be used for welding large pieces of aluminium, grip marks are put in the cavity before the die is heat treated.

CHARACTERISTICS OF COLD WELDING

• At least one of the metals must be ductile without excessive work-hardening

• Total absence of applied heating

• Dissimilar metals can be joined

• Surface preparation is important

COLD WELDING PROCESS DESCRIPTION

• The parts to be welded are first cleaned.

• A short section of the part is sheared• The parts are clamped in a die with

some initial extension • A forging force is applied to

complete welding.

STAGES OF COLD WELDING

COLD WELDING EQUIPMENT

MANUALLY OPERATED COLD WELDING MACHINE

COLD WELDED PART DIAGRAM

APPLICATION• Cold welded butt joints are used in the

manufacturing of aluminum, copper, gold, silver, and platinum wire

• Most commonly, successive reels of wire are joined for continuous drawing to a smaller diameter

• Aluminum alloys used in cold welding

ULTRASONIC WELDING

Ultrasonic welding is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to work pieces being held together under pressure to create a solid-state weld.

Why to use US welding?• First - Ultrasonic assembly uses ultrasonic vibratory

energy which is transmitted through the parts to melt and bond thermoplastic materials And joining thin sheet gauge metals and other lightweight materials Second - This technique is fast, efficient, non-contaminating and requires no consumables. Third - In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together.

PRINCIPLE

In ultrasonic welding, frictional heat produced by the ultrasonic waves and force is used for the joining process. Ultrasonic waves (15 to 60 kHz) are transferred to the material under pressure with a sonometer. Welding times are lower than 3 s. The welding can proceed with or without the application of external heat.

ADVANTAGES

• Heat affected zone is minimized • Very thin materials can be welded • Surface deformation is minimum• Welding of glass is also possible • No defects due to gases, arc and filler metal• Equipment is simple and moderate skill is enough• Dissimilar materials can be joined

DISADVANTAGES

• Restricted to join thin materials • Competitively not economical • Materials being welded may tend

to weld to the tip and anvil

Application

• Manufacturing of toys• Joining of electrical and electronic components• Welding aluminium wire and sheet• Mobiles, sports shoes , laminations, cars etc• Packing , medical industries, computers.

PRESENTATION NAMEMANUFACTURING PROCESSES IDIFFERENT TYPES OF WELDING

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