АНГЛИЙСКИЙ ДЛЯ СВАРЩИКОВ

What Is Orbital Welding

The term Orbital-Welding is based on the Latin word ORBIS = circle. This has been adopted primarily by aerospace and used in terms of Orbit (noun) or Orbital (adjective) for the trajectory of a man-made or natural satellite or around a celestial body. The combination Orbital Welding specifies a process by which an arc travels circumferentially around a work piece (usually a tube or pipe). The concept Orbital Welding is basically a loosely defined term that is usually used for processes only, where the arc is travels at least 360 degrees around the work piece without interruption. Consequently, processes, which interrupt the full 360-weld sequence such as for better puddle control (often used for MIG/MAG welding, using the down - hand welding sequence in 2 half-circles), can not truly be called orbital welding.

Possibilities and Limitations From welding terminology Orbital Welding belongs to the category semi-mechanized (TIG-) welding. Because of the need for good control of the weld puddle, the Orbital-Welding process is only practiced with the TIG

process and relevant rules like selection of gases, cleanness, weldability of specific materials and consequential mechanical strength specifications such as tensile and bend loading, are very important.

Orbital-welding is presently used whenever the quality of the weld joint has the highest priority. These demands are not only limited to mechanical strength and X-ray qualification, but also to the important aspects of the aesthetics of the weld seam. For any users a uniform, flat and smooth root-pass is the main reason for using this process. Consequently, it is favoured in the following areas: chemical industry, pharmaceutical industry, bio-technology, high-purity water systems, semiconductor industry, aircraft - and aerospace industry. Moreover, because of the weld joint's uniform outside shape and almost complete absence of need for any post-polishing, Orbital-welding is even used for bends on door-handles, hand-guards, or in dead foot-elements for champagne-glasses! Interested applicants for this technology should certainly note that they have to confirm a couple of indispensable premises.

The following presents the basic rules for this process, valid for all manufacturers and systems.

Even knowing that some competitors are announcing features, which would potentially violate the basic physical laws of nature and knowledge, moreover, making promises and statements which are at least detected as impossible to meet when the welding system must work under high duty - cycle production conditions. Indiscriminate and exactly defined dimensions with tolerances must be thorough and complete. The much liked standpoint, that the welded tubes and pipes are in accordance to DIN or ASME standards are not acceptable criteria. These qualifications only define tolerances in percentage to the wall thickness relating to pressure loading and not to weldability using the Orbital-Welding-Process.

For the Orbital-Welding-Process absolute tolerance values are necessary, and furthermore, the more complicated the application, the tighter the tolerances must be. This means, that for an easy application like welding a stainless steel tube of 53 x 1,5 mm, a tolerance in alignment of about 0,5 mm (about 30% of the wall thickness) can be compensated, but for much more critical applications like welding a carbon-steel pipe of 114,3 x 3,6 mm, the same percentage can result in unacceptable weld quality. Therefore, the question of acceptable tolerances should be researched and defined for each application individually.

That Orbital-Welding can be used successfully and economically is proven by the constantly increasing number of users. Field experience has shown that Orbital-welding can be justified based upon economic reasons alone, where the welds can be done in squared-butt no-gap preparation utilizing a single pass. With advanced digital welding systems this is possible up to a wall-thickness of 4 mm, and with welding systems with lower performance capabilities (limited levels, no pulse-synchronized cold-wire - feeding), up to 3 mm.

Joint preparation is simple but requires high quality with an exact 90'b0 angle to the tube/pipe axis; a high quality saw cut is usually enough. Of course, the joints should be deburred and cleaned out of corrosion, oil, tinder, etc. With appropriate quality-demands, this should be even obvious for manual welds! The tube joints will be then fit together without any visible gap. This can be done with small autogenous tack-welds or with internal or external clamping fixtures. For larger wall-thickness it is necessary to bevel the weld-joints, far as possible in a U-shape. Since a very precise and uniform root pass is important, a weld joint is prepared with an. I. D. related and fixed bevelling-machine. Manual grinding or the use of bevelling saw blades is not precise enough for repeatable welding results. Because an Orbital-Welding job usually requires a lot in time and money, the Orbital - multi-pass-welding is not used very often and only where it is strictly recommended on quality reasons. A good qualified manual welder will, in most cases, be faster than an Orbital-welding-system. Additionally, an Orbital-system for multi-pass welds will be much more expensive and even more complicated than a system without this option.

Visual inspections of the weld-seam clone can never be sufficient as the sole criterion. Other quality controls, such as, corrosion, consistency, mechanical strength must also be considered. Also, allowed tolerances in contents of alloys on specific materials, such as sulphur content, can result in significantly different welding results, even when the material code is the same. Usually, you can expect that stainless steel materials up to 3 mm wall - thickness can be done without filler-wire. For higher wall-thickness applications, you have to decide on a case-by-case basis. In some eventualities even carbon steel can be done without filler-material, although it's even recommended on the thinner wall-thickness to use filler-wire in any way.

After reading activity

Find the English equivalents in the text for the following word combinations:

противоречить законам физики, обращаться вокруг обрабатываемой детали, иметь первостепенное значение, контроль сварочной ванны, красивый внешний вид сварного шва, гладкий и ровный проход при заварке корня шва, шлифовка вручную, приемлемый допуск,

недопустимое качество сварки, квалифицированный сварщик, содержание серы, механическая прочность, искусственный спутник, система высокой очистки воды, обязательное условие.

Speaking

True or false?

1. Orbital Welding is a process, where the arc travels at least 360 degrees around the work piece with some interruptions.

2. MIG/MAG welding, using the down-hand welding sequence in 2 half­circles, refers to orbital welding.

3. Puddle control is very important for Orbital welding.

4. The number of Orbit Welding users stays the same for a long period of time.

5. Aerospace industry is the only area of Orbital Welding application.

6. Joint preparation is not necessary.

7. Orbital-welding-system is very fast and cheap.

8. Filler-wire is used for all wall thickness applications.

Describe Orbital welding by completing the following sentences:

1. The term Orbital comes from the Latin word ORBIS and means... . 2. The Orbital Welding is a process in which an arc travels... . 3. By category it belongs to... . 4. It is practiced only with... . 5.Orbital-welding is presently used in such areas as. . 6. It is used to produce. . 7. The basic rules for

this process are. . 8. Absolute tolerances in Orbital-Welding Process are

important because. . 9. Wall-thickness of 4 mm is possible. . 10. Joint

preparation includes. . 11. Orbital-multi-pass-welding is rather expensive

and its use is only justified when. . 12. Filler-wire is necessary to use only

Answers from a survey of industry leaders give valuable feeedback on the state of welding for the year 2000 and beyond.

By Andrew Cullision and Mary Ruth Johnson

The pulse of the welding community beats strongly heading into the 21st century and overall projections for the future are generally optimistic, but a few gray clouds roam the horizon. Those sentiments were expressed by respondents to a recent Welding Journal survey. To get a firm feel for that pulse of present and future conditions in the world of welding, the Editors queried AWS Sustaining Member companies, which include producers of a variety of welded products, providers of research and design services and manufacturers of welding equipment, consumables and accessories.

The Editors would like to thank all those who took the time to put down their thoughts and ideas on paper. The responses were diverse, direct and, most of all, very interesting. Those questions and a summary of their answers are presented below.

- Do you believe welding will be used more or less in the next decade? If more, where do you see the growth? If less, why do you believe so?

The majority of respondents feel welding is here to stay and will be used more in the future, although many qualified their answers, and there were a few dissenting voices as well. Steve Sumner, manager marketing product development, Lincoln Electric Co., replied positively, "Welding will continue to be used more in the future because it has proven to be a productive and cost-effective way to join metals." He went on to speculate that "the consumer welding market will continue to provide opportunities for growth," with home improvement and the retail infrastructure to support it becoming a "burgeoning market." One respondent felt that for cost- competitive reasons industry will continue to replace mechanical joining with semiautomatic and automatic joining processes, giving a definite boost to welding. David Landon, corporate welding engineer, Vermeer Manufacturing Co., said, "More, because welding is the most effective way to join materials for structural integrity. Growth will be in alternative materials such as plastics, composites and new alloys." Phil Plotica, senior V. P., sales and marketing North America, ESAB Welding and Cutting Products, replied,

"Overall, I expect welding growth will keep pace with growth in the GNP. Some specialized segments, such as aluminum, will grow faster than others, while the continuing developments in nonmetallic materials will slow some segments."

The feeling that growth will be in specialized areas was repeated often. Areas that were mentioned included welding automation, GTA welding because of the increasing need for accuracy and precision in welding new metals; GMA welding with mixed gas shielding; sheet metal industry; construction industry; infrastructure repair; transportation industry; marine structures; aerospace; and automotive, especially its use of aluminum alloys. Some feel the growth will primarily be in countries with emerging economies, while the growth in the United States will be relatively stagnant. Terry O'Connell, V. P. sales and marketing, Genesis Systems Group, commented, "The U. S. welding market is flat to declining. Growth is expected in Mexico and other developing countries. Labor shortages in the U. S. will contribute to a steady growth in the robotic welding market." Joe Scott, president, Devasco International, Inc., echoed the sentiment, "Less in the U. S. with expectations of a slight decline in the economy, as well as the continuing transition to a service/information economy. Outside the U. S., growth is expected as economic stability returns to troubled regions and their need for infrastructure grows."

The perspective of some, though, is that welding will be used less in the future. Chris Anderson, product manager, Motoman, Inc., opined, "There will be less welding in the next decade. The number of welded products will remain the same, but designs will be more efficient to minimize the amount of welding."

- Which welding process (es) will see an increase in use and which will see a decrease in use during the next decade?

There was much speculation as to which processes would see more use in the future, but almost unanimously the process chosen for decline was shielded metal arc welding (SMAW). A very few speculated a decline in the use of gas metal arc (GMAW) and gas tungsten arc welding (GTAW).

A significant group felt the continuous wire processes (FCAW, GMAW) would experience the most use. The GTAW process was the next most mentioned. One of the reasons stated for its increase was "the need for high-quality work on thin materials."

Don Connell, welding engineer, Detroit Edison, stated, "Any process that can be automated will increase." Landon also had the same perspective, "GMAW will increase along with automation." But he also speculated, "Low-fume generating processes will increase." The concept of increased use of automation at the expense of semiautomatic operation was voiced throughout.

The laser beam welding process was mentioned for future growth, and the specialized process friction stir welding was also targeted for expanded use. Other processes mentioned for increased use were resistance welding, plasma arc welding and capacitor discharge welding.

- Do you foresee a shortage of skilled welders in your area of business during 1999; in the next decade?

Without question, the majority of replies indicated there is a shortage now and there will be a shortage in the future. The breakdown was 72% consider the situation problematic now and for the long term, 14% did not see a shortage and the remaining 14% either see no shortage now, but expect one in the future or see a shortage for 1999, but not for the future.

John Emmerson, president, Magnatech Ltd. Partnership, made a typical comment for those who see a far reaching problem, "There is a shortage of skilled welders everywhere in the world, and it is only getting worse as each year passes. Despite the fact that welding is used in virtually every industry, it seems virtually ignored as a manufacturing science. Connecticut [the state of location for Magnatech], for example, dropped its Vo-Tech welding classes in 1997. In addition, population dynamics in recent years in the U. S., Europe and Japan indicate that the next decade will see a much smaller number of young people entering the work force. This, by itself, will result in fewer welders."

ESAB's Plotica had a similar take on the situation, "There is a shortage of skilled welders now in most major market areas, and this shortage will worsen unless substantial programs are implemented to promote welding as an attractive career choice for young people."

Landon of Vermeer Manufacturing stated, "We have had a shortage for the past five years. I see no turnaround, and we will not see a turnaround until the establishment acknowledges welding as a viable career path. To meet our immediate demands, the company has developed its own welder training program. The company is also involved in proactive programs that make instructors at high schools and area colleges aware of welding as a viable career."

Connell of Detroit Edison, does not see an immediate problem, as he encouragingly stated, "There is a renewed interest in the boilermaker's welding program, bringing in a good influx of people. I don't foresee a shortage in 1999." Another respondent took a contrary view, noting a shortage of skilled welders in 1999, but projecting a leveling of demand in the next decade.

J Julio Villafuerte, director research and development, Tregaskiss, had a slightly different perspective. "The need for plain skill welders will decrease slightly with the slowdown of manual welding. However, the need for welding engineers will increase dramatically as welding automation becomes more prominent."

- Where do you see the use of welding automation heading in your industry?

If there is any one thing to bank on for the future, it is the increased use of automation in welding operations. There was an overwhelming affirmative from our respondents on this point, although it was not completely universal. The perspective of those few who did not see increased use might be expressing an influence from their particular industry. A structural steel fabricator mentioned the difficulty in automating for weldments that do not have a high degree of repetitiveness and variations in fitup and joint geometry. Another individual felt automation will not replace welding equipment for manual operations if the equipment is developed to be fast, safe and economical.

But by far the majority feel the same as Magnetech's Emmerson, who stated, "We see more and more companies of all sizes automating applications that were being done manually. Many are exploring their first use of automation, and the declining number of skilled welders will continue this trend." The lack of, or declining numbers of, skilled welders was frequently mentioned as reason for the growth of automation.

Philip Winslow, V. P. sales and marketing, Hypertherm, Inc., noted another often stated reason, "Usage will increase, primarily because of the consistency it gives to welding and cutting operations, especially with CNC (computer numerical control) and robotically controlled processes." Lincoln's Sumner was emphatic in his assessment, "Automation is the single most important growth sector in the welding industry. The drive for higher productivity and reduced costs will keep automation at the forefront." Other reasons for the increasing use of automation included safety and the effort to remove the welder from tiring, repetitive conditions and long-term exposure to fumes.

Chip Cable, president, Bug-O-Systems, isolated shipbuilding and the trucking and railroad industries as areas that will experience growth in automation. A fabricator of offshore steel structures has targeted automation for heavy tubular splices, plate girders and process piping. Small companies and job shops are anticipated to at least try robotics and CNC equipment.

- What are the strengths of the welding industry? What are its weaknesses?

Although our respondents listed plenty of strengths and weaknesses for the welding industry, Plotica of ESAB, perhaps best summed up the two most commonly held opinions. Regarding the industry's strengths, he said, "We are a well-established, mature industry, with a solid track record in technology and process advancements." And as to its weaknesses, "We are not attracting enough young people into welding careers," Plotica said. "Welding is still perceived by many as a crude and dirty process."

While many saw the industry's maturity - the reputation of welded components for being reliable and economical, the industry's commitment to research and development and the dedication of its work force - as signs of its strength, nearly as many others saw it as a weakness. They believe the industry is set in its ways and slow to change. According to one respondent, the industry's strength is that the people involved in it are "slow to change, with a show me attitude." On the other side of the coin, he said, "Its weakness is that they're slow to change even after you show them." And while a number of respondents lauded the industry's commitment to research and development, others claimed it's too esoteric and takes too long to transfer from the academic level to the factory floor.

Thomas C. Conard, president of Alexander Binzel Corp., had another take on the industry's weak spots. He noted welding is not a separate industry in and of itself but instead makes up part of many other industries. The implication here might be that welding lacks a clear-cut image and direction.

- What business improvements during the next ten years would be in your company’s best interests?

As might be expected, there were nearly as many different answers to this question as there were respondents. These ranged from broad-based desires, such as a wish for growth in any field that uses metallic materials, to a more narrow focus, such as wanting increased use of electronic commerce and supply chain management. Better trained workers, improved communication techniques, designing for manufacturability and lessening the time it takes to get new products to market were all mentioned as in companies' best interests. Several persons called for increased automation.

Several respondents said a change in the government's role with regard to their operations would improve their businesses. This could occur either through less government involvement or through such things as restriction of imports, "reasonable environmental legislation that does not drive up the cost of doing business," tort reform in product liability and lower taxes.

"We spend a tremendous percentage of our income toward research and development," explained Emmerson of Magnatech. "The continuation of tax credits for small company R&D would be beneficial. We note that several of the Canadian provinces are very aggressive in nurturing technical innovation and the growth of small companies, and allow virtually all R&D expenditures to be written off against income. I believe there would be an explosion of new development and company growth if any of the state governments undertook similar tax credit programs."

- What has to be done in the future to keep the welding industry healthy?

More than 50% of the respondents believe improving the image of welding so top students will be drawn to the industry and bettering training methods for welders and welding engineers are the keys to welding's future.

We need to "totally revise the public education system in the United States to acknowledge the trades as an acceptable alternative for students," according to Connell of Detroit Edison. This echoed the opinion of David Yapp, team leader, arc welding and automation, Edison Welding Institute, who said there needs to be "a radical change in education at all levels." He added, however, "This is not likely to happen without strong leadership and commitment."

In fact, respondents touched on a variety of aspects related to training - all with an eye toward welding's future. In the opinion of Jackie Morris, quality manager at Bender Shipbuilding & Repair Co., Inc., the level of cooperation between manufacturers and schools must improve so that manufacturers' needs are met. Genesis' O'Connell said the welding industry needs to do two things: "Enhance ease of use through technical training and technology advancement," and "concentrate on making welding the low cost, best performance choice for material joining." For the question regarding welding's weaknesses, Anderson stated it's "often not scientifically applied, which leads to overdesigned weldments and process parameters that are not optimized." Anderson touched on the topic again in answer to the above question, when he said, we must "continue to educate students on the basics of the process and how to implement it. (We must) teach the economics of welding to designers so they understand the costs of a weld."

Respondents also mentioned improved salaries for welders, staying ahead of environmental and health issues and more practical research and development as ways the welding industry can help itself stay healthy.

- Are you optimistic or pessimistic about the future of your particular industry?

Overwhelmingly, the respondents to the survey said they were optimistic about the future of their industries. In fact, 92% of respondents indicated they are at least guardedly optimistic about the future. One respondent summed up his reasons this way: "Metallics will be around for a long time and they will need to be joined."

Much the same opinion was held by Lincoln's Sumner. "I am optimistic," he said. "Even though we are mainly tied to the steel industry, which has seen a slight decline, we have much more to learn about welding and furthering the process of joining metals. I believe products and services that the welding industry provides will continue to be in demand worldwide."

Paul D. Cunningham, president of Weldsale, indicated he was optimistic because "gains in technology via software and the Internet will help increase productivity in the U. S.A." Winslow of Hypertherm foresees a bright future: "If we improve our understanding of our worldwide customers' needs, we have a road map to unrestricted growth."

However, some respondents, such as Thomas A. Ferri, a welding process specialist with Airgas, expressed optimism while adding a word of caution. Ferri said he was "optimistic so long as we know our industry needs some changes." Morris of Bender said he was "optimistic in that shipbuilding and repair is a sound profession with an increasing market; pessimistic in that environmental restraints are greatly increasing operating costs and decreasing profit margins. There is a need for better dialog between industry and the private sector."

- During the 1990s, the trend has been for company buyouts and mergers. Do you see that trend continuing and is it healthy for your industry?

Not all of the respondents answered both parts of the above question. From the answers received, three times as many respondents believed the trend for company buyouts and mergers will continue. Several stated, however, that the pace will slow from that of the early 1990s. Besides slowing down, "a certain degree of counteraction, i. e., divestitures, may also begin to take place," according to Plotica. "For the most part, the buyouts and mergers have been healthy by providing resources and growth opportunities to small- to medium-sized companies that would have not been possible otherwise." With regard to it being a positive trend, most respondents agreed with Plotica. In fact, three times as many respondents stated it is a healthy trend as opposed to those who believe it is not good for industry. "Every buyout and merger has victims and winners," one respondent said. "It also creates opportunities. Ultimately the industry does become more efficient, which is healthy."

It appeared, however, that respondents who work for welding equipment and consumables manufacturers rather than end users were more likely to consider it a negative trend. "The welding industry is getting smaller every year," one respondent wrote. Another said, "Who's left to buy without creating an antitrust monopoly issue?"

Langdon of Vermeer presented a case for both sides. On the positive side, Langdon said, "Larger companies have more resources for research and development. Also, mergers present a larger buying power and, in some cases, allegiances to manufacturers. Some of the buyouts that we are seeing, especially in the equipment rental industry, could be a real boon to our company." On the negative side, "less competition," he said.

While stating that "company buyouts and mergers can have very positive benefits for the industry and the consumer," Emmerson also put in a word of caution. "To use an overworked phrase," he said, "if there are no 'synergies' between a group of companies beyond the fact that they are associated with the welding industry, the risk is that the performance of small, newly acquired companies will suffer as their original owners bail out and no strong management fills the void."

Sumner voiced the opinion of several respondents when he said, "I believe that these consolidations have fostered an environment that is healthy for the industry with more focused competition between larger manufacturers. This competition is good for all of us to help move the industry forward and provide customer solutions."

Conclusion

Since time machines still exist only in the stories of H. G. Wells and other works of science fiction, no one can tell us exactly how welding will fare in the 21st century. However, the people who responded to the Welding Journal survey represent a cross section of fabricators of welded products and producers of welding equipment and related products. Together they offer a wide range of experience and knowledge. Answering the questions separately, in their respective cities, they still formed a consensus. They agree the future looks promising for welding. It remains and will continue to be a productive, cost-effective manufacturing method. However, steps must be taken to bring more skilled personnel into the industry, or changes must be made to accommodate for the lack of skilled personnel (e. g., welding automation). They also indicated the welding industry must embrace all of the modern-day technological tools to keep pace with the rest of the world.

Continue the list of optimistic and pessimistic scenarios for welding technology development in the future.

1. Производители сварочного оборудования, приспособлений и присадочного материала уверены, что их рынок сбыта будет в дальнейшем расширяться.

2. Технологии получения механических соединений будут вытесняться в промышленности полу - и автоматическими технологиями соединений, что приведет к дальнейшему развитию сварки.

3. Для сварки новых металлов потребуется большая точность.

4. Даже на малых предприятиях могут появиться роботы и оборудование с числовым программным управлением.

5. Для успешного развития сварочных технологий необходимо привлекать высококвалифицированный персонал.

6. Стремление к увеличению производительности и сокращению расходов делает необходимым дальнейшую автоматизацию сварочного производства.

7. Поглощение и слияние компаний, занятых в сфере производства сварочного оборудования и расходных материалов, будет в ближайшее время продолжаться.

8. Научные исследования и опытно-конструкторские разработки положительно сказываются на качестве сварочного оборудования и расходных материалах.

9. Сварка в настоящее время остается одним из эффективных и рентабельных технологических процессов.