The Science of Stick Metal Arc Welding
While there are many different types of welding, the goal is always to join together two pieces of material. In the case of stick metal arc welding (SMAW), a metal stick which generates an arc of electrons from an electric power source is used. This arc, which works like a torch, then becomes a tool that cuts through metal. Here's a deeper look at the science of stick metal arc welding.
Basic SMAW Fundamentals
Primary advantages of SMAW include versatility, affordability and simplicity. This type of welding is used for a wide range of projects.
The power source for a SMAW project can be either AC or DC for both stationary and portable welding machines. Since direct current is more stable than alternating current due to providing a steady flow of electrons in one direction, it creates a more smooth welding experience. On the other hand, AC is easier to use and more energy-efficient. The metal rod driven by an electrical source serves as an electrode. Different types of welding rods, identified usually by a letter and four digit numbers (as in E7018), have different functions and amperage capabilities.
Some of the variables that determine successful welding performance includes rod angle positioning, arc motion, speed, temperature, and precisely managing the weld pool. This puddle results from the base metal reaching its melting point. It is protected from damaging contaminants in the atmosphere by the shielding gas from flux, which keeps the metal surface clean. It's important for the joint surface to be free of paint, rust, dirt, dust, oil and moisture.
Confident, focused and steady manipulation of the weld puddle is essential to achieve professional results. Therefore, it's crucial to be relaxed instead of tense, which can lead to erratic motion. A welder, for the sake of performance and safety, must be comfortable and free of distractions.
Fast freeze rods have a strong arc which helps remove surface impurities. The welder can use an uphill, downhill, side-to-side or circular motion during the welding process. It's a useful approach for pipe welding, tacking up weld joints, working with rusted metal or filling gaps. Filler rods don't penetrate metal as deeply as fast freeze rods but allow for easier melting and are useful for quicker jobs. Many other electrodes that come in various sizes can be used, depending on the purpose.
The welding machine is attached to a ground clamp. The rod can be used like a match to strike the area where the weld is conducted, but the welding machine must first be calibrated for the rod. As current flows through the rod, the temperature of the arc can get as hot as 7,000 degrees Fahrenheit or hotter.
Welding gives off UV radiation from the arc, similar to sunlight. So you need to be very careful not to burn yourself or the effect may feel like a sunburn. It is vital to protect your body, hands and eyes from being exposed to the arc. Cancer can develop from multiple burns, so it's essential to have a clear understanding of the risks involved.
Heavy clothing and goggles that allow clear vision will help protect your skin and eyes. Professional welders make sure they use the proper gloves designed specifically for SMAW. It's also important for welders not to breathe in toxic fumes, so a ventilation fan is useful in confined welding areas.
Any type of welding requires experience and skill to achieve professional results. When you need a skilled professional to help with your projects, contact Southwest Industrial Rigging at 602.278.6281 for your rigging, welding and fabrication needs.