The Impact of Teaching Oxy-Fuel Welding on Gas Metal Arc Welding Skills

Industrial technology programs around the country must be sensitive to the demands of manufacturing and industry as they continue to replace “vocational” curriculum with high-tech alternatives. This article examines whether or not teaching oxyacetylene welding in the industrial technology classroom is required to learn arc welding processes. The results of this study suggests that there appears to be little impact, in terms of gas metal arc welding skills, associated with removing oxyacetylene welding from the curriculum. Because the gas metal arc welding industry is growing globally and industrial technology curricula are under time constraints that often limit the amount of time devoted to welding, faculty should consider suspending oxy-fuel welding to allow more time in gas metal arc welding instruction. Disciplines Agriculture | Bioresource and Agricultural Engineering | Engineering Education Comments This article is from The Journal of Technology Studies, 34, no. 1 (Spring 2008): 2–11. This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/abe_eng_pubs/52 2 The Impact of Teaching Oxy-Fuel Welding on Gas Metal Arc Welding Skills Sergio D. Sgro, Dennis W. Field and Steven A. Freeman T h e J o u rn a l o f Te c h n o lo g y S tu d ie s Industrial technology programs around the country must be sensitive to the demands of manufacturing and industry as they continue to replace “vocational” curriculum with high-tech alternatives. This article examines whether or not teaching oxyacetylene welding in the industrial technology classroom is required to lear n arc welding processes. The results of this study suggests that there appears to be little impact, in terms of gas metal arc welding skills, associated with removing oxyacetylene welding from the curriculum. Because the gas metal arc welding industry is growing globally and industrial technology curricula are under time constraints that often limit the amount of time devoted to welding, faculty should consider suspending oxy-fuel welding to allow more time in gas metal arc welding instruction. Introduction and Background Many industrial technology programs struggle to identify and institute cur ricular activities that adequately serve all of the needs of local and regional industry. In light of “new” technologies, such as CNC, CAD/CAM, and the ever-growing robotics and automation markets, it is no surprise that the perceived importance of vocational skills steadily decreases. But the emphasis during the past decades to pursue less physically demanding careers has resulted in profound labor shortages throughout almost all industries (Brat, 2006), particularly manual welding, as evidenced by a recent Wall Street Journal Online Marketplace article: The average age of welders, currently 54, keeps climbing. As a wave of retirements loom, welding schools and on-site training programs aren't pumping out replacements fast enough. As a result, many companies are going to g reat lengths to attract skilled welders, sending recruiters to far-away job fairs and dangling unprecedented perks. (Brat, 2006, p. 10) Industrial technology programs around the country must be sensitive to the demand for welders as they continue to replace “vocational” curriculum with high-tech alternatives. Entrylevel managers who understand the practical as well as the theoretical nature of technology are still required. “The primary distinguishing characteristic of technological knowledge is that it derives from, and f inds meaning, in activity” (Herschbach, 1995, para. 28). Much of the f acility and vocational equipment infrastructures in industrial technology programs remain intact, albeit a bit dusty, and they should be utilized to revitalize or reorganize hot metals curricula to meet the demands of industry. This article delves into welding education as its authors consider which processes, if any, are helpful for the student to lear n first if he or she is to become prof icient in arc welding. In particular, the researchers have chosen oxy-fuel welding (OFW), also known as oxyacetylene welding, and gas metal arc welding (GMAW) as the two test vehicles. Oxy-fuel welding is the oldest welding process that burns oxygen and acetylene in a flame to melt metal be yond its solid state. It has been largely superseded by arc welding (American Welding Society [AWS], 2004). Gas metal arc welding continues to grow globally (Pekkari, 2000) and is used extensively in “industrial manufacturing, agriculture, construction, shipbuilding and mining” (AWS, 2004, p. 148). Gas metal arc welding uses an electric power source, rather than a flame, to produce an arc that melts metal be yond its solid state. Literature Review State of the Welding Industry “The highly increased consumption of solid wires in 1999 over 1998 by almost 35 percent (in USA) reflects extremely good business conditions” (Pekkari, 2000, p. 3). Pekkari (2000) also explained the immense shift from manual metal arc (MMA) (also known as shielded metal arc welding or “stick”) to gas metal arc welding in the last quarter of the 20th century. In 1975, manual metal arc utilized just over 50 percent of all arc welding; by the turn of the century, the number had fallen to approximately 15 percent of arc welding. Contrary to its counterpart’s demise, gas metal arc welding has ballooned from approximately 20 percent of all arc welding to almost 60 percent (Pekkari, 2000). In fact, Pekkari continues this comparison with the following statement, “The number of arc welding 3 applications has continuously been growing since 1975” (2000, p. 5). More impor tant, many more shops and manufacturing facilities look to robotic welding for reduced production time and increased quality (Harris, 2005). In 2002, the U.S. Department of Commerce (2002) released a study entitled “WeldingRelated Expenditures, Investments, and Productivity in U.S. Manufacturing, Construction, and Mining Industries.” The first two major f indings of the report represent credible evidence regarding this study that industrial technology students must be adequately prepared to manage current welding technology as effectively as possible within the limited time allotted in the classroom. Those findings are as follows (U.S. Department of Commerce, 2002, p. 1): 1. Welding expenditures represent a substantial contribution to the U.S. economy. 2. By far, labor represents the largest proportion of total welding expenditures. Recently, The Wall Street Journal Online Edition published an article describing how manufacturers, both large and small, are dealing with a shortage in qualif ied welders (Brat, 2006). From an educational standpoint, teachers also should be prepared to purchase or update existing equipment that will aid in the prepara tion of the managers. The need to consider costs is an important component of curriculum considerations. Cost Considerations for the Metals Lab Incurred costs fall under four areas: equipment costs, energy costs, labor costs, and material costs (AWS, 2004). Of particular interest to this research are equipment costs and student contact time (actual time welding) on the equipment. The following is a general introduction to the equipment and its use. Oxy-fuel Welding Equipment Oxy-fuel welding equipment, also known as oxygen acetylene welding, is relatively inexpensive, portable, and versatile (AWS, 2004). It is used for welding, cutting, brazing, and soldering. A proportionally equal mixture of oxygen and acetylene is burned at a temperature of 5,589o Fahrenheit (Althouse, Turnquist, Bowditch, Bowditch, & Bowditch, 2003). Equipment costs, excluding rented gas cylinders, can range from several hundred dollars (torch outf it and gas regulators) to approximately $1,000.00. Students must f irst learn to light the oxyfuel flame, adjust the neutral flame, and heat up the base metal before beginning to weld. These steps alone, notwithstanding the dangers and nuances of gas regulators and the addition of filler metal, can absorb a lot of class time. This is especially critical for schools that have limited space and limited time in the cur riculum allocated to welding. In this situation, a student could spend most of his or her time adjusting the flame, heating up the base metal, or tr ying to understand the two-handed coordination of creating a puddle, adding f iller material, and moving the puddle. Gas Metal Arc Welding Equipment Unlike oxy-fuel welding, gas metal arc welding equipment can range from about $2,500 for a stand-alone welder up to $9,000 for a multi-process welding machine. Most gas metal arc welders now come equipped with recommended weld settings for wire speed and v oltage. Students are generally able to quickly set dials or similar apparatuses to the intended material thickness and begin welding. No time is needed to adjust the flame, heat up the base metal, or learn how to add f iller material into the weld puddle; this is done automatically. Travel speed comparison Given that welding is a physical activity, an important function in student learning is allotting as much practice time as possib le. One aspect of this learning time can be a function of the welding travel speed. “Travel speed is defined as the linear rate at w hich the arc is moved along the weld joint” (AWS, 2004, p. 183). Table 1 is an approximate travel speed comparison between oxy-fuel and gas metal arc welding of 0.1875 inch mild steel thick plate. Some of the time difference between welding T h e J o u rn a l o f Te c h n o lo g y S tu d ie s Table 1 Travel Speed Comparison – Oxy-fuel Welding Versus Gas Metal Arc Welding Welding Type Approximate travel speed (inches per minute) Oxy-fuel gas welding Gas metal arc welding 2.8 (Althouse, et al, 2003)