welding technology - nikhil

WELDING

BY-NIKHIL ANAND SRIVASTAVA3rd YEAR - MECHANICAL ENGG.SEC - JROLL NO - 02

Welding is the process of permanently joining two or more metal parts, by melting both materials.The molten materials quickly cool, and the two metals are permanently bonded. Spot welding and seam welding are two very popular methods used for sheet metal parts.

Introduction

GAS WELDING ARC WELDING RESISTANCE WELDING SOLDERING BRAZING

TYPES OF WELDING

Definition :- Metal joining process in which the

ends of pieces to be joined are heated at their interface by producing coalescence with one or more gas flames (such as oxygen and acetylene), with or without the use of a filler metal.

GAS WELDING

Arc welding is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point.

ARC WELDING

Resistance welding involves the generation of heat by passing current through the resistance caused by the contact between two or more metal surfaces. Small pools of molten metal are formed at the weld area as high current (1000–100,000 A) is passed through the metal.

In general, resistance welding methods are efficient and cause little pollution, but their applications are somewhat limited and the equipment cost can be high.

Resistance Welding

Spot welder

SOLDERING

Soldering is a process in which two or more metal items are joined together by melting and

flowing a filler metal (solder) into the joint, the filler metal having a lower melting point than the workpiece

BRAZING Brazing is a metal-

joining process whereby a filler metal is heated above melting point and distributed between two or more close-fitting parts by capillary action.

CARBURIZING FLAME -temp 3150 *C NEUTRAL FLAME -temp 3200 *C OXIDIZING FLAME -temp 3500 *C

TYPES OF FLAMES

TYPES OF FLAMES

Welds can be geometrically prepared in many different ways. The five basic types of weld joints are 1. Butt Joint 2. Lap Joint 3. Corner Joint 4. Edge Joint 5. T-Joint

Types of Joints

HEAT AFFECTED ZONE

An image of a cross section of a welded butt joint, with shading that shows the locations of the fusion zone (dark gray) and the heat-affected zone (middle shade of gray) in the base material (light gray)

A welding defect is any flaw that compromises the usefulness of the finished weldment.

A welding defect mainly weakens the weld joint.

Welding defect

TYPES OF DEFECT1. Cracks2. Distortion 3. Welding angular distortion 4. Welding shrinkage transverse

CRACKS

DistortionWelding shrinkage longitudinal

Welding angular distortion

Welding shrinkage transverse

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