CHAPTER 10 - Welded Joints - Introduction, Advantages, Welding Processes and Strength of Welded Joints

Oct 23, 2026

Chapter 10, Welded Joints, introduces welded joints as permanent connections formed by fusion of the edges, with heat supplied by gas burning or electric arc welding, and with or without filler material and pressure. It compares welded joints with riveted joints by outlining key advantages such as high efficiency, rigidity, and repairability, and key disadvantages including distortion from uneven thermal cycling and higher inspection difficulty. It then surveys welding processes (fusion vs heat-and-pressure), and explains fusion welding with thermit, gas, and electric arc methods.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages36

Reading Time1 h 31 min

AccessFree to download

10.1 Introduction

10.2 Advantages and Disadvantages of Welded Joints over Riveted Joints

10.3 Welding Processes

10.4 Fusion Welding

10.5 Thermit Welding

10.6 Gas Welding

10.7 Electric Arc Welding

10.8 Forge Welding

10.9 Types of Welded Joints

10.10 Lap Joint

10.11 Butt Joint

10.12 Basic Weld Symbols

10.13 Supplementary Weld Symbols

CHAPTER 10 Welded Joints 1.Introduction. 2.Advantages andDisadvantages of WeldedJoints over Riveted Joints. 3.Welding Processes. 4.Fusion Welding. 5.Thermit Welding. 6.Gas Welding. 7.Electric Arc Welding. 8.Forge Welding. 9.Types of Welded Joints. 10.Lap Joint 11.Butt Joint. 12.Basic Weld Symbols. 13.Supplementary WeldSymbols 14.Elements of a Weld Symbol. 15.Standard Location ofElements of a WeldingSymbol. 16.Strength of Transverse FilletWelded Joints. 17.Strength of Parallel FilletWelded Joints. 18.Special Cases of FilletWelded Joints. 19.Strength of Butt Joints. 20.Stresses for Welded Joints. 21.Stress ConcentrationFactor for Welded Joints. 22.Axially LoadedUnsymmetrical WeldedSections. 23.Eccentrically LoadedWelded Joints. 24.Polar Moment of Inertiaand Section Modulus ofWelds 10.1 Introduction A weldedjoint is a permanentjoint which is obtainedby the fusion of the edges of the two parts to be joinedtogether,with or without the application of pressure and afiller material.The heat required for the fusion of thematerial may be obtained by burning of gas(in case of gaswelding)or by an electric arc(in case of electric arcwelding).The latter method is extensively used because ofgreater speed of welding. Welding is extensively used in fabrication as analternative method for casting or forging and as areplacement for bolted and riveted joints.It is also used asa repair medium e.g.to reunite metal at a crack,to build upa small part that has broken off such as gear tooth or torepair a worn surface such as a bearing surface. 342■ A Textbook of Machine Design # 10.2 Advantages and Disadvantages of Welded Joints over Riveted Joints Following are the advantages and disadvantages of welded joints over riveted joints. Advantages 1.The welded structures are usually lighter than riveted structures.This is due to the reason,that in welding,gussets or other connecting components are not used. 2.The welded joints provide maximum efficiency(may be 100%)which is not possible incase of riveted joints. 3.Alterations and additions can be easily made in the existing structures. 4.As the welded structure is smooth in appearance,therefore it looks pleasing. 5.In welded connections,the tension members are not weakened as in the case ofriveted joints. 6.A welded joint has a great strength.Often a welded joint has the strength of the parentmetal itself. 7.Sometimes,the members are of such a shape(i.e.circular steel pipes)that they afforddifficulty for riveting.But they can be easily welded. 8.The welding provides very rigidjoints.This is in line with the modern trend of providingrigid frames. 9.It is possible to weld any part of a structure at any point.But riveting requires enoughclearance. 10.The process of welding takes less time than the riveting. Disadvantages 1.Since there is an uneven heating and cooling during fabrication,therefore the membersmay get distorted or additional stresses may develop. 2.It requires a highly skilled labour and supervision. 3.Since no provision is kept for expansion and contraction in the frame,therefore there is apossibility of cracks developing in it. 4.The inspection of welding work is more difficult than riveting work. # 10.3 Welding Processes The welding processes may be broadly classified into the following two groups: 1.Welding processes that use heatalone e.g.fusion welding. 2.Welding processes that use acombination of heat and pressure e.g.forge welding. These processes are discussed indetail,in the following pages. # 10.4 Fusion Welding In case of fusion welding,the parts tobe jointed are held in position while themolten metal is supplied to the joint.Themolten metal may come from the partsthemselves(i.e.parent metal)or filler metalwhich normally have the composition oftheparent metal.The joint surface becomeplastic or even molten because of the heat Fusion welding at 245℃ produces permanentmolecular b

FAQs

What is a welded joint and how is fusion achieved?

A welded joint is a permanent joint formed by fusing the edges of two parts to be connected, with or without pressure and filler material. The required heat comes from burning gas in gas welding or from an electric arc in electric arc welding.

What are the main advantages of welded joints over riveted joints?

Welded structures are usually lighter and can provide very high joint efficiency. Welded connections also allow easy alterations, offer smooth appearance, can be used where riveting is difficult, and produce rigid joints with less time than riveting.

What are fusion welding processes and what subtypes are discussed?

Fusion welding holds the parts in position while molten metal is supplied to form the joint as it solidifies and fuses. The chapter classifies fusion welding into thermit welding, gas welding, and electric arc welding, and explains each process.

Oct 23, 2026

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