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What’s new in the tube and pipe industry?

Figure 1
Seuthe incorporates slides to facilitate tooling changeover.

Few compounds play as large a role in the world economy as petroleum. Whether the price is high or low, it makes headlines and starts water-cooler conversations. The most recent petroleum boom lasted about 10 years and upended many traditional notions about crude oil and the petroleum industry. For example, the higher-than-usual price over the last decade made tar sands extraction viable, allowing Canada to solidify its position as the U.S’s largest supplier (it exceeds all of the Organization of Petroleum Exporting Countries [OPEC] combined). Second, the calls for energy independence from every politician over the last three or four decades quieted as horizontal drilling and hydraulic fracturing helped to expand domestic production, which pushed the domestic supply over the 50 percent mark. Third, it provided more than a few jobs in areas not traditionally known for drilling activity, notably North Dakota.

These days the industry isn’t faring so well.

“The oil industry is like an old, tired, out-of-tune stringed instrument,” said Cornelius Sawatzky, sales manager for Xiris Automation Inc., a manufacturer of inspection and quality control equipment, and the data bears out his assessment. The spot price for a barrel of crude, rarely more than $20 before 2005, peaked at more than $140 per barrel in the middle of 2008. After hovering around $100 per barrel for most of 2012, 2013, and 2014, it slid to less than $30 in early 2016. The number of rotary rigs operating in North America tells another part of the same story: It peaked at 2,026 in November 2011 and fell to 420 at press time (early May). Finally, the population of Williston, N.D., went from 12,000 before the boom to an estimated 40,000 at its height. When the boom ended, it ended quickly, and it changed the fortunes of property owners in Williston in a hurry. The occupancy rate of apartments and hotels in the area was estimated at 50 to 60 percent in late 2015.

Where do other industries stand these days? Automotive did really well in 2015, and it’s not hard understand why. When the crude oil price falls, so does the gasoline price, and everyone with a car notices. No price is posted more visibly than that of gasoline, so drivers are reminded, several times a day, that they have a little more disposable income in their budgets. Put a new roof on the house? Replace that aging furnace? Install a new floor in the kitchen? Nah. In 2015, the auto industry in North America sold more cars and light trucks than in any other year since 2000.

Manufacturing in general hasn’t been as strong as automotive, but it has been improving lately. The broadest measure of manufacturing activity, the PMI®, averaged 50.4 over the 12 months from May 2015 to April 2016. It was less than 50 from October 2015 to February 2016, meaning it was in decline, but it has been positive since then. The Credit Manager’s Index, which tends to lead the PMI, has been climbing since December, rising from 55.0 to 59.8.

This bodes well for all manufacturers and helped to set the tone for Tube® Düsseldorf 2016, April 4-8, Düsseldorf, Germany.

Making Tube and Pipe

In making tube and pipe, two processes dominate the market: forming and welding it on a mill or extruding it from an extrusion press. Some other processes are used for specialized circumstances, such as using a spiral mill for large-diameter, spiral-wound tube or a hydraulic press for making even larger diameters from plate in the UOE process. Several others exist, and many were on display in Germany.

Rounds. Tube mill manufacturer Seuthe believes that control over quality and the delivery schedule starts at home, so the company makes nearly everything for its mills, peripherals, and tooling. Its ability to machine or fabricate nearly everything it needs, right down to the electrical cabinets, means that it is free to design, build, and prove innovative features for its mills—laser mills for stainless steel and high-frequency electric resistance welding (HF ERW) mills for carbon steel—with little reliance on outside sources. It also means that the company can use a one-size-fits-one strategy for building mills and peripheral equipment, tailoring the equipment to the application.

  • Tube and pipe producers who make steel products on HF ERW mills are familiar with scarfing weld beads. Red-hot and razor-sharp, the external weld bead is a hazard in constant motion, moving at mill speed, and the internal weld bead usually becomes a big tangle that isn’t easy to remove from the ID.
  • Laser welding on stainless steel is an entirely different process. The mill runs slower and the welding-and-squeezing process doesn’t generate much excess material. For such mills, Seuthe uses a system of three abrasive belts—two that rotate clockwise and one counterclockwise—to grind down the weld bead. On the ID, the company uses a process called weld bead lamination. Rather than use a scarfing tool on a cantilevered arm to remove the internal weld bead, it uses a mandrel on a cable to condition it.

  • Setting the squeeze pressure on an HF ERW mill is crucial for making good welds. However, making tube is a dynamic process, so the proper amount of squeeze pressure changes as other variables change. A sensor that measures the squeeze pressure in the weld box allows the operator to keep close tabs on this crucial parameter.
  • Every drive system is customized to suit the mill and the products it makes. Some systems use one motor to drive the tooling on a series of stands, but others need more flexibility, so they have one motor per roll stand. Others have the highest possible level of speed control—one motor for each top roll and one for each bottom roll.
  • Saw blades aren’t inexpensive, and neither is coolant. To get the most life out of the saw blades, the company uses a misting system to dispense a precise amount of coolant.
  • On some mills, the roll stands are placed on slides to facilitate easy roll tooling changeover. To take a roll stand offline, a technician uses a wrench to move the roll stand (see Figure 1).

Another slick technology application prepares tube lengths for subsequent drawing operations. A sensor determines the tube’s precise wall thickness and adjusts the cut length so that after cutoff, each tube has the same weight. Because each length contains a consistent volume of material, the subsequent drawing operation produces tubes that are consistent in length.

Figure 2
Rattunde’s ACS® CFM Twin handles tube and bar stock up to 6.65 in. OD, depending on the specific model. Options after cutting to length include deburring, end finishing, and machining.

Small-diameter Rounds. T.H.E. Machines displayed its LSL 012, which makes tubes from 0.039 to 0.47 inch in diameter and wall thicknesses from 0.002 to 0.047 in.

Although this mill handles material that is far thinner than what most tube producers work with, it is essentially the same as any other weld mill. The machine unwinds the strip from a reel, centers it at the infeed to the mill, slits the material to the specified width if necessary, and forms it with a series of opposed roll tools. It uses a laser welder to join the edges; a camera captures the seam’s position and relays this information to a controller that adjusts the laser head’s location to keep the spot centered on the seam. The system floods the ID with an inert gas to protect the weld, and an annealer normalizes it shortly after welding is completed. The system can be fitted with an accumulator for continuous production.

The machine was designed for aluminum, steel, and stainless steel, but this isn’t the end of its applications. It also handles copper, nickel, chrome-nickel, chrome-nickel-molybdenum, titanium, and clad or coated materials.

Squares and Rectangles. Squares and rectangles often are formed indirectly. The forming stages that make a round tube are followed by additional shaping steps that turn the circumference into four flats and four corners. However, a cage forming mill uses a different process, forming squares and rectangles directly from strip.

Olimpia 80 displayed a cage-forming mill at the expo.The cage concept uses a single set of tooling to make any size tube in the mill’s stated range and computer numeric control (CNC) to adjust the tooling positions when changing from one size to another. In other words, it eliminates most of the tooling cost and all of the labor associated with product changeovers. All of the production parameters, including the angle radii, are adjusted from the operator’s console.

Olimpia 80’s model SCF 20-60 is capable of making squares from 0.79 to 2.36 in. and rectangles from 0.79 by 1.57 to 3.15 by 1.57 in., in thicknesses from 0.0039 to 0.16 in. The company’s largest model, SCF 120-300, makes sizes from 4.72 to 11.81 in. The company also uses the cage concept for round tubes. Its smallest, RCF 25-63, makes rounds from 0.98 to 2.48 in. diameter, in wall thicknesses from 0.03 to 0.12 in. Its largest, RCF 270-610, makes rounds from 10.63 to 24 in. dia. in wall thicknesses from 0.12 to 0.79 in.

Exhaust Tubing. Mention the word exhaust to a car enthusiast, and names like Borla, Eberspaecher, Cherry Bomb, Flowmaster, Magnflow, and Thrush® probably come to mind. However, the automotive aftermarket is just one segment of the exhaust industry. The market for commercial truck exhaust systems likewise is sizeable and destined to grow. The number of light-, medium-, and heavy-duty trucks in the EU-23 countries grew from 95,000 to 105,000 from 2012 to 2014. Part of this is a recovery from a downturn that started in 2011, so it’s conceivable that the number will climb to its previous height, 123,000, as the economies of Europe continue to recover.

A key component in truck exhaust systems is a short length of flexible tube, one that couples the exhaust pipe to the muffler. Wecotech developed a machine that uses a roll forming process to shape a strip, then rolls the strip into a circle. In this continuous processes, each revolution locks to the previous one, resulting in a tube that is essentially airtight. It’s compatible with systems that comply with the constantly evolving—European diesel emissions standards Euro IV (2005), Euro V (2008), and Euro VI (2013)—said Rocco Serini, customer consultant for the company.

Xiris’ Sawatzky noted that the commercial truck industry has potential for another reason. The heavy reliance on just-in-time manufacturing means that commercial vehicles get a lot of use, which shortens the replacement cycle.

“Manufacturing uses trucks like they’re going out of style,” he said.

Figure 3
Using a laser to make this bicycle frame allows the designer to incorporate features that would be time-consuming without a laser. Notches for hinge joints (top left) and tab-and-slot construction (bottom right) improve ease of assembly and the component strength. The laser also allows the manufacturer to remove some of the material in an eye-catching pattern (bottom left).

Rounds Made by Orbital Die Forming. Nakata displayed a new concept in a forming mill, one in which the tooling isn’t stationary. Two sets of forming tools, in the form of die blocks, are connected in series and circulate through the mill on two endless tracks. The company dubbed the process orbital die forming (ODF) and said that it’s ideal for making tube from thin or high-strength material.

According to the company, the process combines the advantages of a conventional weld mill (roll forming) and a hydraulic press (the UOE process). The tooling has much larger radii than conventional mill tooling, resulting in substantially less work hardening, similar to that of the UOE process. However, unlike UOE, which makes one length of tube at a time from plate, ODF is a continuous process and therefore has productivity on par with a conventional mill.

Software for the Forming Process and Beyond. The software used in manufacturing usually is used for activities like optimizing a manufacturing process, identifying forming difficulties, or predicting a finished component’s characteristics. It’s not often that these capabilities translate directly into saving peoples’ lives, but they can.

The managing director of software developer data M, Albert Sedlmaier, said that a crash tube in an automobile door can help prevent the door from collapsing in an accident. If the door retains its shape, it can allow the driver and passengers to exit the vehicle, potentially saving their lives.

The software, COPRA® FEA RF, can assist with this because its capabilities do more than simulate the stresses imparted by roll forming. In addition to quality control, error analysis, and control capability, it can help in every development step, from feasibility study to conception to implementation. The company’s products also simulate the entire production chain, including pre- and post-operations such as welding, stamping, punching, and bending.

In the case of the automobile door crash tube, the manufacturer had two tube designs: one with a single bend and another with two bends. In the case of one bend, the software worked with the material’s original properties. In the case of two bends, the software had to simulate the material’s entire forming history to determine the component’s strength after forming.

Bending and Measuring Tube and Pipe

Manufacturing seems to get more competitive every day, and tube fabricators have as many challenges as any other manufacturer—new materials, complex part geometries, cost pressures, and changing batch sizes. Schwarze-Robitec cited these difficulties as the reasons for developing a control system to help operators implement changes reliably. Introduced under the name NxG in 2015, the 2016 update, which simplifies bending and enables networking, is named NxG 2.0.

To make it compatible with Industry 4.0, the company integrated basic modules into the new controller. In addition to the standard statistics on bent components, it gathers and evaluates process data. For example, integrated sensors provide information on wear values or lubricant consumption, allowing the operator to draw conclusions about the expected bending result, the state of the bending tools, or the need for maintenance, contributing to machine uptime.

The human-machine interface (HMI) has been simplified to make it more intuitive and to improve process reliability. It uses icons to keep all machine operations clearly arranged and structured. It uses stylized, meaningful icons for the various operation categories, such as parameters for dimensions, the transport, and tool clamping or guide rails.

“This makes the development of bending programs or the input of tool data easier,” said Managing Director Bert Zorn. “Moreover, all entries are always inspected for validity,” which prevents interferences and crashes.

“We have a complete package of software and hardware interlinked,” Zorn said. “It is a crucial step towards flexible and, at the same time, stable processes.”

For bending long-length, small-diameter tubing for applications such as brake lines and air conditioner condenser tubing, transfluid® developed a robotic handling system and a bundle feeder unit that can process raw tube or tube that has been formed or fitted with flanges. The system uses two 7-axis robots to handle the tube. In handling a tube 14 feet long and 0.71 in. OD, the system can make 47 bends in slightly more than two minutes.

Tube and wire measuring system manufacturer Aicon introduced its latest machine, TubeInspect P16, at the expo. Equipped with 16 high-resolution cameras, it has a measurement area of 8.5 by 4 by 2.3 ft. The user places the component on the measurement table, and the system uses its 16 cameras to make a 3-D image of it. The software compares the print to the actual part to verify the part’s dimensional accuracy.

Suitable for tubes and wires up to 8 ft. in length, it provides measuring results in less than 10 seconds. Tubes up to 23 ft. long can be measured by repositioning the component and taking measurements in several steps. The machine helps to optimize the manufacturing processes by providing measurement data to the bending machines, thereby reducing costs through shortened setup times.

When measuring large objects, especially long, thin tube, accompanying software BendingStudio compensates for sag caused by gravity.

The company also launched the latest revision of its associated software platform BendingStudio 3.0. It connects all the data and processes needed to carry out the manufacturing of bent parts, from production and process planning to manufacturing and quality control. It is the only tool to combine these functions with emphasis on metrological processes, according to the company.

  • The software structure is clearer and easier to handle then earlier versions. Inspection plan setup is separate from measurement functions, so each user sees only the information relevant for the task at hand.
  • The new CAD-WIZARD enables the user to create bending elements for a bending machine from a component’s CAD data in IGES or STEP.
  • The program offers extended measurement options. Instead of wholly automatic measuring, the latest software allows the user to step in when needed, which can be helpful in reverse engineering.
  • Very long and complex parts with many bends that can’t be measured in a single step are measured by taking a series of overlapping measurements. The user repositions the part after each measurement, and the software combines the series into a composite measurement.

Cutting Tube and Pipe

Cutting technologies displayed in Düsseldorf ran the gamut from maximizing cutting speed to maximizing cutting intricacy.

Rattunde’s ACS® CFM Twin exemplifies high-speed cutoff and deburring, specifically for high-volume applications such as automotive. A gripper takes two tubes at a time and presents them to the saw for cutting, then rotates them 90 degrees for end facing. End facing options include a 90-degree face or a 90-degree face with ID or OD chamfer, or all three (see Figure 2). Depending on the process, it can produce more than 5,000 parts per hour.

The company also developed its own system for handling chips and smoke. It uses a cyclone action; the chips fall into a collector, and the smoke rises to an electrostatic system that captures it. It also has options for applications that have strict requirements for the finished appearance of each tube. For such an application, the company can provide a material handling options that prevents dings or burnish marks.

Visitors to TRUMPF’s booth saw a machine capable of complex cuts and a novel application. The company introduced its TruLaser Tube 5000 fiber, which uses fiber technology and the company’s RapidCut function, which superimposes the motions of the tube axis and those of the cutting head. It increases the machine’s productivity by 15 percent, according to TRUMPF.

The machine handles mild steel tube from 0.47 to 6 in. OD and up to 0.31 in. wall thickness, and up to 21 ft. long. Although the wavelength of a fiber laser needs a different level of protection than a CO2 laser, the company’s designers developed a system structure that has the necessary guarding yet provides easy access, according to Product Manager Christopher Boerner. The company also designed a new clamping system that handles the entire diameter range and sets the clamping pressure automatically, which effectively eliminates setup time, he said.

Also on display in the company’s booth was a product that illustrated laser capabilities and an unusual application for stainless steel. ElevenTwentySeven, a Belgian fabricator, designs and builds custom bicycles using component features that would be difficult, some perhaps impossible, without a laser (see Figure 3). For example, the seat tube and down tube have saddle cuts with tabs that the assembler inserts into slots on the crank housing. Each handlebar is formed from a single notched tube that the assembler bends to a 90-degree angle before welding. Making them from a single piece provides more strength than two-piece construction would have.

Another example of fabrication flexibility was displayed in BLM’s booth. Although BLM has been focused almost completely on tube fabrication since the company was founded, in 2015 it rolled out a laser cutting machine equipped with a table for flat products. In Düsseldorf it debuted the LT-Free, capable of cutting tube and other 3-D objects, notably deep-drawn, hydroformed, or stamped parts. The machine uses a single laser source and two cutting tables, and the cutting area can be divided into two booths if necessary. Variations include:

  • One booth, two 5-axis robots: Each cutting table is loaded and unloaded by its own robot.
  • One booth, one robot: The robot splits its time between the two cutting tables.
  • Two booths, no robot: The operator unloads a finished part, then fixtures a new part in booth 1 while the laser cuts in booth 2.

The company outfits the system with a 1-, 2, or 3-kW fiber laser, depending on the user’s needs.

New Alloys for Tube and Pipe

Ovako introduced M-steel® 280, a low-alloy steel developed for turning applications. The key is a calcium treatment that helps to control nonmetallic inclusions, according to the company. The result is an alloy that can be turned at high speed yet still maintain its mechanical properties, according to Ovako. The company has found that a tool used for machining the new alloy can last more than six times longer than the same tool used on a conventional steel.

The company cited reduced machining costs, increased production capacity, and good repeatability as key benefits.

Sandvik Materials Technology rolled out Sanicro 60, also known as alloy 625, for hydraulic and instrumentation (H&I) tubing and heat exchanger applications, specifically for customers installing equipment in harsh environments.

The high-strength, austenitic nickel-chromium alloy is intended for resistance to pitting corrosion, intergranular corrosion, and stress corrosion cracking in chloride-containing environments, including seawater and hot geothermal fluids. Its pitting resistance equivalent (PRE) exceeds 48.

Suitable for chemical processing, power generation, and high-temperature aerospace applications, the material also is available in seamless pipe and high-temperature tubes. It has extremely good corrosion resistance in severe oxidizing and nonoxidizing acids, including hydrochloric, nitric, and phosphoric, as well as in high-temperature applications. Its temperature range is more than 1,800 degrees F, from -321 to 1,500 degrees F.

The grade’s low-carbon content combined with high nickel, chromium, molybdenum, and nitrogen levels provides it with an outstanding resistance to corrosion in chloride-containing environments,

It is supplied bright annealed in sizes from 0.25 to 1.625 in. OD and wall thicknesses from 0.035 to 0.197 in. H&I tubing is available in straight lengths and coils, supplied annealed (grade 1) and solution annealed (grade 2) in most common sizes. The material grade can be welded using standard austenitic stainless steel welding processes. Postweld treatment isn’t necessary because it’s resistant to intergranular corrosion even after welding.

The world’s appetite for electricity is large and growing, and this didn’t escape Sandvik’s attention. While renewables are gaining ground, fossil fuels remain critical to fulfilling the world’s power needs. According to the latest edition of the BP Statistical Review of World Energy, dated June 2015, coal production worldwide grew nearly 40 percent from 2004 to 2014. The company’s alloy Sanicro 25 is intended specifically for the temperatures achieved in coal-fired power stations, supercritical boiler applications, and regeneration applications.

Sandvik also deployed its substantial metallurgy expertise at the expo when it introduced its welding handbook, 400 pages of welding information, available on its website and via a mobile phone application. It provides information and instructions for using the proper amount of welding heat, welding dissimilar metals, and troubleshooting and includes data sheets and safety sheets. It also takes much of the drudgery out of calculating ferrite numbers. The traditional process requires the welding engineer to use several sources to create a ferrite graph, but this application takes the work out of it by supplying the graph.

Looking to 2017 and Beyond

It would be an exaggeration to say that the entire tube and pipe industry’s fortunes rise and fall with those of the oil and gas market, but the two are linked. Sawatzky noted that the industry has plenty of potential, but nobody expects it to rebound anytime soon. In separate reports, the U.S. Energy Information Administration and the International Energy Agency predicted that the crude oil price would remain less than $80 per barrel until 2020.

Until the energy market recovers, tube and pipe producers and fabricators will have to keep an eye on the many other industries that use large amounts of tube and pipe.

About the Author
FMA Communications Inc.

Eric Lundin

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Elgin, IL 60123

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Eric Lundin worked on The Tube & Pipe Journal from 2000 to 2022.