It’s time to transform sparks and metal into art and engineering, one weld at a time.
Shielded Metal Arc Welding (SMAW) has rightfully earned its moniker as the grandfather of welding. Its longevity in the industry is a testament to its unparalleled versatility and accessibility. Few welding processes can match SMAW’s adaptability across various scenarios, making it a cornerstone skill for welders of all levels.
The Fundamentals of SMAW
At its core, SMAW requires a surprisingly simple setup. An electrode, an electrode holder, a ground clamp, a welding cable, and a constant current source are all that are needed to get started. This basic equipment belies the process’s impressive capabilities. Whether you’re working with a transformer rectifier in your garage or a heavy-duty generator at a remote job site, SMAW gives you the power to join a diverse range of metals in locations where other processes simply can’t reach.
Mastering the Perfect Bead
Creating the ideal SMAW bead is an art form that requires a delicate balance of several factors. Amperage, polarity, and arc length must all be precisely controlled while maintaining a steady hand at the crucial moment. Experienced welders develop an almost intuitive sense of their craft, recognizing the distinct sounds and visual cues that indicate a quality weld.
Listen closely, and you might hear the unique sound of a root opening going into a pipe, slowly fading as it ties into the tack. The gentle crackle of an E7018 electrode, as it forms a fillet weld, tells its own story. And when a bead made with a 308-16 welding rod reveals its lustrous surface as the slag peels away effortlessly, it’s a silent confirmation that amperage, voltage, travel speed, and technique have all aligned perfectly.
Building a Strong Foundation: The SMAW Curriculum
At institutions like the Mahoning County Career & Technical Center in Canfield, Ohio, SMAW is often the first welding process students encounter. The curriculum is designed to emphasize adherence to industry codes and standards, preparing students for AWS certification upon course completion. Let’s explore the key components of mastering SMAW.
Lesson 1: Amperage and Electrode Selection
Understanding amperage and electrode selection is crucial for successful SMAW. The curriculum typically focuses on two types of electrodes: the E6010 and the low-hydrogen E7018. Each has its own characteristics that influence machine setup and welding technique.
To determine the right amperage, students learn a simple yet effective method. They take the nominal diameter of the electrode, convert it from a fraction to a decimal, and use this number as a guide for setting the amperage. For instance, a 3/32-inch electrode converts to 0.09375 inches, suggesting a starting amperage of around 93 amps.
Beyond this basic calculation, students are taught to navigate Welding Procedure Specifications (WPS) to find appropriate amperages and other weld parameters. They’re also introduced to various resources, from manufacturer-created apps to textbook tables, all designed to support their developing SMAW technique.
Lesson 2: Refining SMAW Techniques
Mastering SMAW involves learning various techniques for initiating the arc, creating beads, and manipulating the weld pool. Students are taught both the scratch start and tap techniques for initiating the arc, while also learning the importance of avoiding arc strike marks that could lead to weld rejection.
The stringer bead method serves as an introduction to creating a weld bead. This fundamental technique helps students master critical aspects such as arc length, work angle, travel speed, and pool control. As they progress, students learn about different weave patterns – including U, J, and circular – and various weld pool manipulations.
Proper care and handling of electrodes is another crucial aspect of SMAW. Students learn about the special requirements of low-hydrogen electrodes and the industry standards governing their use. They also study proper weld cleaning techniques, referencing section 5.30 of the D1.1 standard.
Lesson 3: Embracing Modern Welding Technology
While SMAW is one of the oldest welding processes, modern technology has enhanced its capabilities. Students are introduced to advanced welding machines from various manufacturers, learning about features that can improve their SMAW welds.
Arc force control, also known as the dig function, is one such feature. It helps prevent electrode sticking when the arc length is too short, improves pool control during out-of-position welding, and can reduce or eliminate undercutting.
Another beneficial feature is the hot start function. This provides additional current at the start of the weld, ensuring quick and reliable starts, immediate joint penetration, and improved tie-ins on previous welds or tack welds.
Understanding these technologies adds depth to students’ knowledge, bridging the gap between traditional techniques and modern industry practices.
Lesson 4: Ensuring Weld Quality
Quality is paramount in welding, and SMAW is no exception. Students learn to perform visual inspections of their welds, identifying discontinuities and rejectable defects. They become proficient in using nondestructive examination gauges and learn to assess weld bead profiles, including leg and throat sizes for fillet welds and weld reinforcement for butt joints.
The lab class standard typically mirrors the visual criteria set by the D1.1 structural code. This allows students and instructors to assess welds, identify necessary corrective actions, and determine root causes for any discontinuities.
Conclusion: SMAW as a Career Cornerstone
Shielded Metal Arc Welding is more than just a technique – it’s a fundamental building block for a successful welding career. The principles learned in SMAW transfer to all other welding processes, making it an invaluable skill for any aspiring welder.
From simple repairs to complex, x-ray-level code work, SMAW’s versatility makes it an indispensable tool in a welder’s arsenal. By mastering SMAW, welders develop a deep understanding of what constitutes a quality weld and how to consistently produce high-quality results.
The integration of modern technologies ensures that this time-honored process remains relevant and viable in today’s welding industry. As the gateway to numerous opportunities in welding, proficiency in SMAW can open doors to a rewarding and diverse career.
In the end, success in welding all starts with knowing how to lay down a quality shielded metal arc weld. With dedication, practice, and a solid educational foundation, aspiring welders can master this fundamental skill and set themselves up for a bright future in the welding industry.
Source : December 2022 Volume 101 Number 12 PG 64 “How to Make a Quality Shielded Metal Arc Weld”