Getting together on the tube

It may be one of the less exciting materials in terms of transport manufacturing, but without precision tubes our planes, trains, automobiles and ships would soon grind to a halt.

Companies supplying these materials to the aerospace sector have to provide high grade products which pass many industry and customer certifications. Two of the most established companies in the precision tube industry are UK-based Fine Tubes and its US sister company, Superior Tube.

In recent years the two have worked increasingly closer in order to offer their customers a more comprehensive service.

“Previously, the owners operated the companies as separate entities,” explains Fine Tubes' aerospace product manager, Paul Mallet (pictured top). “Fine Tubes dealt with the European market and Superior Tube dealt with the US. Now that both mills are part of Ametek, we have been promoting cooperation and now work as partners collaboratively to serve our customers.”

Ametek recently announced the acquisition of both Fine Tubes and Superior Tube. The two mills join Ametek as part of its Electromechanical Group (EMG); a differentiated supplier of electrical interconnects, precision motion control solutions, medical components, specialty metals, thermal management systems and floor care and specialty motors.

Superior Tube's aerospace product manager, Wade Burchell adds: “When we get enquiries we look to see which location best suits the customer's requirements and who can provide a better service, although if it's an existing customer of the respective companies we don't disrupt those relationships.”

As a result of this cooperation, Fine Tubes and Superior Tube are able to offer customers a full service from the initial consultation through to final delivery anywhere in the world.

The companies' breadth of services include: R&D, technical advice on the selection of materials, design, toolmaking and parts development, alongside facilities that include pilger mills, weld mills, draw benches, coil drawing capabilities, bull blocks, controlled atmosphere annealing and heat treatment furnaces. Other facilities include a pickling and passivation plant, eddy current and ultrasonic inspection and radiographic examination.

Long history

Both companies' association with aerospace dates back to their origins. One of Fine Tubes early projects was supplying tube for the Vickers Viscount turbo prop airliner in the 1950s.

Superior Tube has supplied products for the Bell X1 rocket plane which broke the sound barrier, NASA's Apollo programme and the F-15.

“Superior Tube started in 1934, and we have supplied aerospace companies almost as long,” Burchell says. “For aerospace we supply super alloys including Waspaloy, and we are also certified to supply stainless steel 21-6-9. Our main customers currently are the big aerospace OEMs. We are also involved in the nuclear industry but a lot of those nuclear applications are for ships and aircraft carriers.”

In the aerospace market the companies' tubing is used mainly for engine components and hydraulic systems.
Mallet explains: “The largest volumes tend to be supplied to customers working on these applications but our precision tubes are also used for conveying fuel, oil, and air. There are also mechanical applications for operating flaps and slats in wings. Some tubing is also used for structural support.”

Aerospace places additional demands on tube suppliers such as Superior and Fine Tube.

“You have to reach the specification requirements, but most of the time we go beyond these to demonstrate a level of even higher quality not necessarily required for the application,” Mallet affirms. “We also have to be technically competent in order to develop solutions for our customers.

“The driver for most aircraft in terms of material solutions is weight savings, so anything that offers this benefit is at a premium. That can mean either higher strength alloys, thereby allowing you to have thinner wall products or lighter alloys. This is why titanium has become popular. Even if you have the same size tube, in terms of OD and wall thickness, you save weight.”

Customer communication

There are ongoing exchanges to find ever lighter and stronger materials from Fine Tubes' customers such as Rolls-Royce and its suppliers down the supply chain.

Mallet continues: “We constantly try to bring new alloys to the table. For example, Fine Tubes was the first European producer of titanium grade 9 for hydraulic tubing, and we are one of the few mills that makes titanium grade 5 tube for the aerospace industry.”

New materials can be applied both to new build projects and in some instances upgrading to newer materials on older designs.

“We build relationships with our customers based on engineering expertise when evaluating cost or weight savings,” Burchell comments. “One customer wanted to make a part with a convoluted shape out of very thin walled tube. They approached us to see if we could provide a different alloy to see if there would be a weight reduction. Eventually they rejected the new alloy because although it saved weight, its durability and lifespan was less and countered any cost saving in the long term. However, it proves the engineering excellence and expertise that is resident at our sites to help provide tailored solutions which are a benefit to our customers.”

One of Fine Tubes' more recent projects has been supplying tube used on Airbus's A380 and A350 planes that can work at higher pressures.

“One way of saving weight is to use higher pressure in the hydraulics,” Mallet explains. “A traditional plane, for example the A320, operates at 3,000psi. On the A380 and on the A350 they work on 5,000psi systems. These higher pressures systems function with smaller diameter tube, replacing the traditional larger diameter and heavier tubing. It also produces quicker reaction times when the pilot presses the controls.”

The companies supply both seamless and welded tube for aerospace, depending on the material or application. Most of the welded tube is seam integrated (i.e. by redrawing the material through cold working, homogenisation occurs strengthening the weld and substantially reducing the external visible seam.

So what are the latest developments on the horizon for both Fine Tubes and Superior Tube?

Mallet says: “There is the prospect of new grades of titanium with higher strength and less weight. We have carried out development work to show that we can successfully produce tubes in these higher strength grades and that they can be bent successfully.”

Burchell concludes: “We have recently won a contract with a major OEM, which is a first for Superior, supplying high grade stainless steels, which is a very positive development. We are also working on welded titanium products.

“The biggest strength for both companies is the quality that we offer. There are a lot of tube companies out there but if you want to customise products for size, wall and precision requirements, then you have to come to someone like Superior Tube or Fine Tubes. In aerospace you have tighter tolerances and you have to be able to produce exactly what is required because that is a big factor in weight reduction. And of course quality also has a very important impact on reliability.”

www.finetubes.com

www.superiortube.com