In the process of design and planning of engineering projects, the engineers involved have to determine what equipment and material is perfect for that specific task. One of those decisions includes whether to use welds or bolts for the job, which is stronger?
Welds seem to be much stronger than bolts, nuts or rivets because when welding, you heat the material and stimulate its molecules. The extreme heat force results in the fusion of two or more distinct nuclei sharing a common electricity cloud.
In most constructions, the type of joints used depends on the overall design. Still, there are different points to consider when making these decisions. In this article, I’ll compare welds and bolts side by side, using several factors. I’ll also state the advantages and disadvantages of welding over bolts.
Comparison Between Welds and Bolts
Joint Adaptability Comparison: Welded joints are tougher than bolted joints, because of the persistence of the cross-section. Bolted joints on the other hand, are linked with plates or angles, and the deviation of these elements during load transmission adds flexibility. As a result, bolted joints give room for more activity with fewer silhouette problems.
A disadvantage with bolted joints is the supplemental machinery needed for installation, and this restrains their usage. Welding is more adaptable, as almost any two joints can be welded together and new components added to current fusions with ease.
Structural Implementation Comparison:
Welded joints by the standard are firmer than bolted joints, by and large, because their substance doesn’t have the openings required for bolted joints. When it comes to joint capability, the creation process is the determinant factor. While bolted joints provide unsophistication, welded joints offer better strength.
I’ll recommend welded joints when the silhouette performance of a job is more important than cost.
Survey Difficulty in Both Methods: In bolted joints, surveyors must confirm that the bolt projection is zilch or positive. This is because having the rim of a bolt inside the nut is wrong. Surveyors must ensure to fasten the bolts, and when needed check if the rims are taken off.
Welding surveyors’ procedures differ from project to project. The visual survey is the most popular and it is performed prior, during, and post welding. Other survey techniques require professional equipment, which costs more and requires certified surveyors.
As a statement of fact, the survey of welded joints is more expensive and difficult to manage.
Cost Comparison: The price of both bolted and welded joints depends on the job at hand, but bolted joints are normally the less expensive choice. The cost of bolted joints often varies with steel prices, but their production process is automatically efficient, compared with welded joints.
Welded joints are only performed by certified engineers, and their rates per hour can be on the high side. On the contrary, the workmanship cost involved with fastening bolts is much lesser. If the cost of the project is a major concern, bolted joints will commonly be the preferred option.
Installment Process Comparison: There are essential distinctions between the installment process of bolted joints and welded joints. Construction supervisors must take note of them in order to oversee the project effectively.
As normal, bolted joints are easier to regulate, and are often installed with an impact extraction or a simple spud extraction.
Bolted joints are also repaired with ease, and this helps to save time in unforeseen situations. Bolted joints give a fastener installment in the filling as well. Welding is done manually by a professional welder. Different tool types and power sources will be required, depending on the kind of weld.
Safety Comparison: Shielded metal arc welding (SMAW) is a popular safety technique. It is a procedure where an electric arc is generated between an overlayed metal conductor and the steel components to be fused. Welding is carried out in the project field or in a factory, but there are precise grade and safety demands in both cases.
Welding is a dangerous job and optimum precautions are necessary to eliminate accidents. Welders stand the risk of visual impairment, fume/gas inhalation, electrocution, and UV radiation exposure. In contrast, bolting has no particular risk associated other than working at elevations.
Workplace safety measures are imperative join-type regardless, but welding involves more task-related risks. While bolted joints are simple and cost-effective, they lack structural efficiency. On the other hand, welded joints are firmer but cost more and are difficult to manage.
Advantages of Welding Over Bolts
- Welding is a durable attachment technique. After completing a weld, you will have to damage or rapture the parts to be able to disassemble or destroy it.
- Bolting two elements doesn’t make them permanent. Their parts can be easily dismantled if one of them is destroyed or has expired.
- Depending on what welding technique is used, welding can produce a ceaseless joint with lower strain concentrations. While bolting will often possess strain concentrations on each of the bolts.
- Since welding can be incessant, it is applied in conditions in which a hermetic seal is needed. To achieve a hermetic coat with a bolted joint demands extra elements, specifically seals.
- Welding joints can connect either similar or dissimilar joints. For example, aluminium and steel.
- Welded joints components are fastened tightly so they can create leak proof joints without leakage.
- Welding joint elements possess high load carrying capacity even though the joint equipment has lesser weight.
Disadvantages of Welding Joints
- Welded joints are fragile and so their fatigue endurance is less than the joint components.
- Due to unequal heating and cooling of weld components during the welding, the members may distort. Thus generating additional stress.
- Experienced labour and electricity are essential for welding. This makes the cost of the process increase.
- The inspection of welding work is more difficult and costlier than the riveting work.Inspection process of welding process is very difficult because this process is operated at high temperature.
- Some flaws like incomplete penetration, slag, and internal air pockets are not easy to detect.
In conclusion, I don’t consider any option superior to the other, since the most appropriate option changes in line with the project. Ultimately, the type of joint required will depend on project specifications and the owner’s discretion.
