316L Stainless Steel: The Metal du Jour of the Apple Watch

“With stainless steel, we’ve given a traditional material a new expression.”

Using these words, with a backdrop of Epic Music, Apple’s SVP of Design Jonathan Ive concludes his introduction of the Apple Watch with a flourish, in a video featured on Apple’s site.

apple watch stainless steel closeup
Screenshot from Apple Inc’s video of the 316L stainless steel used in the Apple Watch…but of course one can’t embed it on their site, so you’ll have to watch it on theirs. www.apple.com

Launched concurrently with Apple CEO Tim Cook’s speech unveiling the Apple Watch this March, a series of videos highlights the “game-changing-ness”(as they see it) of the Watch, but the ones of interest to us were, of course, those that spotlight the aluminum and stainless steel used in the gadget’s construction process.

FREE Download: The Monthly MMI® Report – covering the Stainless/Nickel markets.

What Is 316L Stainless Steel?

Not only is it strong, shiny, it’s extra-hard too – much like Arnold Schwarzenegger in his iron-pumping salad days.

So how is 316L different from vanilla 316 series stainless? Whereas straight-up 316 is an austenitic chromium-nickel combo containing moly, for corrosion resistance, 316L has a lower carbon content, which helps the metal post-welding, while retaining corrosion resistance. (A main difference between 316 and 304 being that 316 can handle higher temperatures better.)

According to AK Steel,

Type 316L is an extra-low carbon version of Type 316 that minimizes harmful carbide precipitation due to welding. (Ed. note: to be technically specific, whereas the composition of 316 contains a max of 0.08% carbon, 316L contains a max of 0.03%.)

Typical uses include exhaust manifolds, furnace parts, heat exchangers, jet engine parts, pharmaceutical and photographic equipment, valve and pump trim, chemical equipment, digesters, tanks, evaporators, pulp, paper and textile processing equipment, parts exposed to marine atmospheres and tubing.

Type 316L is used extensively for weldments where its immunity to carbide precipitation due to welding assures optimum corrosion resistance.

Another typical yet niche use: watch casings, now including Apple Watch.

Steel Parts of the Apple Watch

As Ive lays out in the video, Apple’s planned obsolescence just got a bit tougher – or at least the material of its latest product has.

Apple takes 316L stainless and then customizes it through “a series of alloying and processing steps” to make their cases even stronger, putting it through a cold-forging process. Impurities are minimized, hardness is ensured. The forgings are then milled in a “12-station multi-access milling machine” achieving “highly accurate uniformity across the case.” It’s then expertly “polished to a mirror finish.”

The Milanese watch-band loops are each woven together from fine steel coils to create a ‘flowing mesh’ with a fabric-like feel, while the links bracelet is made up of around 140 individual parts.

All of this won’t help you when you lose it in a cab or have it stolen, but it sure tries its mightiest to justify the $549 base price!

Why 316L for Apple Watch?

According to our in-house stainless expert, Katie Benchina Olsen, sweat is salty so it makes sense to use a stainless that resists chlorides. “My husband Jeff (not a stainless expert) says that the stainless Apple Watch will protect it from even the sweatiest of wearers,” she said. Another reason for 316L could be that if one were to get ketchup or some other sauce on it, it will resist pitting better.

Are You a Metal Buyer? Need to Track 316L Stainless Surcharges?

Because we got ’em.

According to Olsen, mills actually produce 316/316L, meaning it’s dually certified; in other words, 316L is certified to 316, as it meets the 316 standard as well.

Our MetalMiner IndX℠ features upwards of 25 price points for 316/316L-and-related surcharges, including the following:

  • 316,316L,316LN-Coil from AK Steel 
  • 316/316L 2.5-Coil from Allegheny Ludlum
  • 316/316L-Bar from Outokumpu
  • 316/316L-Coil from NAS
  • 316L 11 Ni-Coil from Outokumpu
  • 316L 16.25 Chrome-Coil from Allegheny Ludlum
  • 316L 2.5 Moly-Coil from Outokumpu
  • 316L w/2.75min Mo-Coil from AK Steel
  • 316L-Other from Carpenter

Perhaps Apple’s suppliers have checked out our IndX℠, the largest database of stainless surcharges in the world…have you?

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