Welding

Welding

Welding

07/11/16

“How can we make a high strength connection between two mechanical parts using heat?”

When trying to mate two parts, engineers often run into an issue. Sometimes, conventional methods such as brazing and soldering are not enough, and a more powerfull process is required. However, thanks to the ingenuity of humanity, a new process has been made to solve this road-block. What if we took the two conjoining surfaces, melted them a bit, and then attached the two heated areas together? Not only is this process very effective, but it also very convenient. Scientists and Engineers have termed this process welding. There a many types of welding

One possible methods of welding uses an electrode (a welding rod) to carry electric current to weld the metal. The wire for the electrode is covered in flux for protection, and an electric arc is created along the electrode the melt the metal, generating temperatures of nearly 3600 degrees Celsius!. In addition to the high intensity heat, the subject metal is shielded to be protected from reactive elements in the atmosphere. This process has been termed Shield Metal Arc Welding. This method is often used in steel erection, heavy equipment repair, construction, and pipeline welding. The advantages of using SMAW is that it’s portable, low cost, has no need for a shielding gas and can work on unclean materials, while the disadvantages are that it requires a high level of skill to use, generates a large amount of waste and does not work on thin metals.

Another welding method can be achieved by using a non-consumable tungsten electrode to heat the base metal and create a molten puddle, all while being protected by a shielding gas. This process has been termed Gas Tungsten Arc Welding, since both gas and tungsten are used in this process. The common applications for this method is aerospace welding, piping systems, and motorcycles. The advantages of this method include the fact that it produces clean, high quality welds, it can weld very thin materials (in contrast to SMAW welding), It can fuse a large number of alloys, it creates splatter free weld, and has highly aesthetic weld beads. The drawbacks of using  GTAW is that it requires high operator skill, it is very costly, has lower deposition rate, needs an external gas, and materials must be completely clean.

Next up, is an interesting combination of the above mentioned methods. This method uses a continuously fed electric current to melt a joint (like the SMAW), while being protected by a shielding gas (like the GTAW). This process is known as Gas Metal Arc Welding. GMAW is often applied to small to large manufacturing, auto-body uses, and fabrication. The strengths of using this process include being very efficient (therefore producing little waste), needs lower heat inputs, a minimal weld cleanup, and being comparatively easy to learn. The drawbacks of using this method include a requirement for a shielding gas, having limiting positions, high equipment cost, can not wield thick materials, and material must be free of dirt and the like

The final process is very similar to GMAW, but with one fundamental difference: it uses a tubular filled wire filled with flux instead of a solid wire. Engineers have termed this process Flux-Cored Arc Welding. This method comes in two variants, self-shielding which only uses the flux to protect the arc with no gas and dual-shielding that uses both the flux and the gas. FCAW can often be found being used with thick materials, steel erection, and heavy equipment construction or repair. The strengths of this process include a higher electrode efficiency, lower heat inputs, minimal weld cleanup, reduced welding flames, and no need for external shielding gas. However, the drawbacks of this system must be discussed, as it creates slag, is not recommended for thin materials, generates a lot of smoke, and has a high price tag for the equipment

All in all, welding is a fascinating and diverse process that has implementations in many disparate possibilities.

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