Shape-memory alloy makes its way from space to sea

If metal that changes shape with a gust of warm air sounds like something that came from outer space, that’s because it did.

The metal — known as shape-memory alloy — has been used in aerospace for decades, but it’s just beginning to make its offshore drilling debut.

Fullerton, Calif.-based Aerofit is pitching the metal as a way to transform the connection of pipes and couplings, replacing welding to dramatically speed up the process and ensuring tight, unbreakable fittings.

The secret behind the magic is that the metal has a kind of memory triggered by temperature changes, allowing it to be one shape when cold, and another when warm.

Aerofit produces ribbed sleeves, made of a titanium-nickel blend it calls Tinel, that are smaller in diameter than the pipes they are intended to connect. When dipped in liquid nitrogen, these cold couplings can be expanded and widened temporarily so they easily slip over the pipe.

“As long as we keep it cold, it’s going to stay expanded, and we can pass the pipe through,” said Peter Lewis, a technical sales engineer with Aerofit who was presenting at an Offshore Technology Conference panel on adaptive technology.

As the pieces warm up, they effectively remember their original cold-forged size and shrink back to the smaller diameter, creating a permanent, unmovable clamp in the process.

A big benefit, Lewis said, is that the process is near error-proof.

“It doesn’t matter if it was installed on Monday morning or five minutes before the end of the shift on Friday evening,” Lewis told the OTC attendees. “The coupling doesn’t care. It works exactly the same; it is always going to work.”

“It is not process dependent,” Lewis added. “The user just has to put it in the right place.”

In aerospace applications, the technology is especially well-suited for working with metals on highly refined, specialized equipment — such as satellites — where welding could be destructive.

In the oil and gas industry, the couplings can replace potentially thousands of welds on a single Christmas tree used at wellheads. Workers have to be trained in safe handling of the cold components, usually deformed and presented at the worksite in liquid nitrogen, about 200 degrees below Fahrenheit.

It generally isn’t cost effective for massive pipes; the sweet spot tends to be in pipes under two inches in diameter.

The same alloy and couplings are undergoing testing now in a subsea environment, subject to a non-disclosure agreement with Aerofit. But the company is just starting to branch out into oil and gas applications. As such, this is the company’s first time presenting or showing at OTC, though business development manager Myrone Vasquez said he visited the massive industry trade show last year.