Welded joints stand out as the most versatile type of joints, capable of joining any two sections in any situation with utmost efficiency. Over the past few decades, these connections have gained popularity due to their numerous advantages and the advancements in automatic welding techniques and expertise. In this article, we will explore the advantages and disadvantages of welded joints in steel structures, providing a comprehensive analysis of their merits and limitations.
Advantages of Welded Joints
Strength:
As the welding process involves the fusion of base metals, creating a joint that is often as strong as, if not stronger than, the base material itself. In some types of welded joints, the strength of the weld is equal to that of the parent metal in the case of butt weld joint.
Rigidity and Durability:
The welding provides exceptionally rigid and durable joints in comparison to bolted and riveted joints. When two metal pieces are welded together, the welding process melts and fuses the base materials, creating a continuous and strong bond. This fusion results in a joint that is highly resistant to bending, twisting, and shearing forces, providing enhanced structural integrity.
Economical:
Welded joints offer cost-effective solutions in terms of labour and material expenses. Welding eliminates the need for additional components like filler plates, gusset plates, and connecting angles commonly required in other types of joints. Additionally, welded joints allow for the use of smaller-sized members compared to those required in riveted connections, making them more practical and efficient.
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Easier Fabrication:
The use of welded joints or connections, particularly in the case of a circular steel pipe, simplifies the fabrication process of complex structures. When dealing with intricate designs or complicated structural elements, welding provides a more efficient and practical solution.
Adding the advantages of easier fabrication, welded joints offer greater flexibility when it comes to making alterations or additions to existing structures. Welding allows for modifications to be made directly to the welded joints, facilitating easier integration of new elements or adjustments without compromising the overall integrity of the structure.
Reduction in structure Weight:
This is another advantage which is contributed by two primary key factors: the elimination of additional fasteners and the ability to use smaller-sized members. In contrast to riveted and bolted joints, welded joints eliminate the need for additional fasteners like bolts or rivets. This reduction in fasteners can significantly decrease the overall weight of the structure.
Aesthetically Appealing:
Aesthetics may not always be the primary consideration in structural design, but the visual appeal of welded structures can play a significant role in architectural, industrial, and artistic contexts. Welded structures often exhibit a more aesthetically pleasing appearance as the welded joints create a smooth and seamless transition between the connected components in comparison to riveted and bolted ones.
This seamless transition is due to the elimination of additional protruding fasteners or visible connections, which otherwise can create a more fragmented or cluttered appearance. The presence of these fasteners may result in irregularities or interruptions along the surface of the structure, affecting its overall visual cohesiveness.
Also, read: Comprehensive Guide To Tension Members In Steel Structure
Disadvantages of Welded Joints
Requirement of Skill Labour:
Welding requires skilled labourers who possess the necessary knowledge, training, and experience to perform the welding process correctly. Skilled welders are proficient in understanding welding techniques, interpreting welding symbols, selecting appropriate welding parameters, and operating welding equipment safely. The precision and quality of a welded joint heavily depend on the skills and proficiency of the welder.
Another disadvantage under the same category is the inspection of welded joints. This also demands skilled labour for necessary inspection and welding works while semi-skilled labour can do the riveting work (Punima. p789).
Expansion and Contraction:
Materials used in construction, such as steel, are subject to temperature variations, which cause them to expand or contract. These thermal changes can exert significant stress on the structure if not properly accommodated. In welded connections, where two or more components are joined together, the lack of flexibility can result in stress concentrations.
Material Distortation:
Welding involves the application of high heat to melt and fuse the base materials. During this process, the localized heating and subsequent cooling can cause uneven temperature distribution across the welded joint and the surrounding material. This uneven heating and cooling can lead to thermal expansion and contraction discrepancies. The uneven distribution of heat can cause the material to undergo distortions, such as warping, buckling, or bending.
Also, read: Types Of Steels And Their Usage In Construction
