3D Printing Doubles the Strength of Stainless Steel (sciencemag.org)

sciencehabit writes: Researchers have come up with a way to 3D print tough and flexible stainless steel, an advance that could lead to faster and cheaper ways to make everything from rocket engines to parts for nuclear reactors and oil rigs. The team designed a computer-controlled process to not only create dense stainless steel layers, but to more tightly control the structure of their material from the nanoscale to micron scale. That allows the printer to build in tiny cell wall-like structures on each scale that prevent fractures and other common problems. Tests showed that under certain conditions the final 3D printed stainless steels were up to three times stronger than steels made by conventional techniques and yet still ductile.
The work was done using a commercially-available 3D printer, according to Science magazine. "That makes it likely that other groups will be able to quickly follow their lead to make a wide array of high-strength stainless steel parts for everything from fuel tanks in airplanes to pressure tubes in nuclear power plants."

Comments

Re: Metal and Plastic

[DontBeAMoran]

That very similar to what happened to me. I needed eight plastic end caps for square metal tubes. I could've gone online to order injection-molded ones at $2 a pop, pay $20 for shipping and wait almost a week to receive them or just 3D-print them myself at $2.50 a pop and have them the day I needed them. Bonus points: I could have them in any colour I wanted as long as I had filament in that colour!

...but I didn't have the colour I wanted on hand, so I went online and paid $40 for a spool of filament, paid $20 for shipping, waited a week to receive it and then spent the day printing them.

The morale of the story is, if you have a 3D printer, make sure you have your favorite colours of filament in stock. Not everything has to be black or white.

what "steel yourself" really means

[epine]

Just last night I read an entire chapter of Rust: The Longest War (2016) devoted to Harry Brearley, one among many to discover stainless steel, but the first who completely refused to shut up about it.

It was obvious to many involved that stainless steel cutlery (and certain engine parts) was the way of the future, but it took decades for most innovations in steel to find widespread commercial adoption, because every new steel at first mainly served to ruin available tooling.

I'm sure there was a slow back and forth between improved tooling, and adjusting the stainless steel to best get along with the improved tooling, but it was always slow work, and usually outside of the five-year investment cycle that made your boss loud and proud of your accomplishments.

That's why it finally took a nutter to not shut up.

Jonathan Waldman has done quite a bit of research and his writing style has an engaging tone, but there's also some kind of weird semantic deficit in his narrative structure that's difficult to diagnose in a single pass.

Be prepared for loosely grouped splotches of colour. This book has high geek appeal, but will irritate actual historians and engineers.

Re: Metal and Plastic

[Solandri]

Even at a thousand times the cost of other methods, that would still be quite useful.

While there are a myriad of factors which go into selecting the proper material for a design, the general criteria that steel is best at is strength per unit cost. If you can pay more, more exotic materials like titanium, tungsten, chromium, or amorphous ("glass") metals are stronger per unit volume than steel. If you need lighter weight, aluminum and magnesium tend to have more strength per unit mass. If you need temperature resistance, niobium, molybdenum tend to be better. etc.

That said, a 2-3x strength increase is just huge, and could upset some of the generalities I listed above. It's been a decade since I delved into materials science, but a 2-3x stronger steel could displace both glass metals for strength per volume, and aluminum for strength per weight.

The latter would have serious implications for the aerospace industry. The big drawback of aluminum (other than relatively low melting point, which isn't an issue in subsonic flight) is that it has a fatigue limit. With a steel structure, you can design it so that repeatedly flexing it no longer causes it to weaken. Aluminum has no such point - flexing it will always cause it to weaken (which is why it was stupid to make Curiosity's wheels out of aluminum). Fatigue failure of aluminum has been the cause of numerous airliner accidents, from the original de Havilland Comet, to Aloha 243, to JAL 123 (greatest loss of life from a single aircraft accident). It's why pressurized airframes are retired and destroyed after about 75,000-100,000 flights. If 3D printed steel has a higher strength per weight than aluminum, it would revolutionize aircraft design.

Why one material?

[John.Banister]

If they have micron scale control, why continuously print from one material? Couldn't they make a structural center alloy that makes a gradual change (in a subsurface adjustment zone) into a protective surface alloy? In the center, they could even print micro-scale collection of overlapping unyielding hard plates for ultra impact resistance joined by a perfectly formulated softer steel for macro-scale malleability.