Stainless Grade Equivalents

Bob La Londe · 2011-04-12T03:15:19+00:00

I have need of stainless for various applications and to be frank the local stores just don't stock much. The box stores have a modest selection, but its all no grade listed Hillman crap. Their stainless is worse than their packaged screws if that's possible.I would like to have some idea what to search for for grades equivalent to steel grades. Like what stainless bolt would I look for to be roughly equal to a grade 8 steel bolt? A grade 5? Never mind grade 2. Like I said, "the box stores have Hillman crap."

Apr 12, 2011 24 Replies

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Harold & Susan Vordos 15 years ago

I'm afraid I'd have to agree, but you may not enjoy success buying such a critter. However, if one chooses to make high strength stainless hardware, you might consider exploring 17-4 PH, as well as 416 stainless. Each is heat treatable. 416 is a sheer pleasure to machine, and capable of achieving a Rockwell C hardness of 35. 17-4 PH can be considered a stainless replacement for chrome moly (4140), and capable of achieving a tensile strength of up to 200,000 psi, and a hardness of 44 Rc.

There are other options, including A286.

Harold

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Pete Keillor 15 years ago

Hmmm. I can't recall the grade of stainless we used in cell tooling, but that sounds kind of familiar. Anybody know a SS that handles 700 C without losing too much strength? We used it to make all sorts of tools for working in a very large experimental electrolytic cell.

I remember operating a clamshell bucket about 2' across, mounted on a

4" dia. piece of stainless. The clamshells had connecting rods to a sliding collar which was actuated with other rods to pneumatic cylinders 5 or six feet higher attached to the lifting bracket bolted to the central shaft. The whole thing was suspended from the smaller bridge crane in the building.

We'd remove a 6' on a side hatch over the sludge chamber, lower that tool in after suitable heatup, flip a switch for the air solenoid on the crane pendant, then raise the closed clamshell full of sludge and molten salt and dump through a hatch into a sludge cart on rails below. It was something to see at night, although certainly no steel mill.

Made lots of other tools out of the stuff, too. Most stainless loses a lot of strength at that temp.

Pete Keillor

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Jeff 4 years ago

Monster Bolts has a great Metric Bolt Grade Markings and steel strength chart that quickly and easily shows the differences between stainless and alloy steel materials. Of note, there are different A2 variations. Both A2-70 and A2-80 may be called A2, but A2-70 (700 Mpa) and A2-80 (800 Mpa) vary by almost 15% in absolute strength.

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Jeff 4 years ago

there is a great Metric Bolt Grade Markings and steel strength chart that shows the differences between stainless and alloy steel materials.

Of note, there are different A2 variations. Both A2-70 and A2-80 may be called A2, but A2-70 (700 Mpa) and A2-80 (800 Mpa) vary by almost 15% in absolute strength.

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