This week we will begin digging into the wonderful world of how stainless steel fasteners are name and hopefully have some laughs along the way!
Today we’ve got part 2 of our series exploring the differences between the various types of stainless steel. Let’s pump some stainless steel!
(But like, without the steroids… or maybe with… Pete is back here rage-pecking at his keyboard as he responds to y’all’s RFQs #boomers)
So, first what do I mean by nomenclature? It’s a system of naming things. In science they’ve got biological nomenclatures for assigning scientific names to discovered species or chemical nomenclatures for assigning names to specific compounds.
So let’s talk about the names of stainless steel fasteners and which ones cross-over between the various standardizing bodies like ASTM, DIN, ISO, ANSI, JIS, etc.
Say my name, say my name!
18-8 stainless steel is sitting in class on the first day of school. The teacher calls out “18-8” are you here? 18-8 raises it’s hand and say’s…
“It’s pronounced A2”
I tried really hard to say my student's names right, but back when I taught high school science, I ran into names that were not pronounced like they are spelled all the time. Eh, blame it on Euro-centricism, I guess? This was always a disaster on the first day of school...
You guys have seen that Key and Peele skit right? if not, you NEED to: https://www.youtube.com/watch?v=Dd7FixvoKBw
I would always play this for my kids on the first day of class. It’s worth giving a watch during the work day (unless you work for one of those lame companies that don’t allow their employees to watch YouTube at work – then you’ll have to wait until you get home). You can thank me later.
Break it down now!
A2 Stainless Steel is recognized by the following standardization organizations: AS (Australia), GB (China), GOST (Russia – and seems fitting for some reason), IRAM (Argentina), ISO (International), JIS (Japan), NBR (Brazil), PN (Poland), SAE (USA), and UNI (Italy), along with several other more proprietary standardizations.
The letter “A” stands for austenitic as opposed to “C”, which stands for Martensitic, and “F” which stands for Ferritic. We will explore the differences between these in a later article.
Some organizations, like DIN (Germany), technically call out A2-12H, A2-20H, A2-21H, A2-25H, A2-30H, A2-40H, A2-025, A2-035 or A2-040 which are a reference to a more specific type of A2 stainless steel. We will break that down in just a moment.
For example, a screw might be A2-50, but a set screw with relatively equivalent properties might be A2-12H. Both represent a relatively softer austenitic stainless steel in the A2 grade. See the chart below for further examples:
Notice how the flow chart starts with Austenitic, Martensitic or Ferritic. Generally, Eurolink only works with Austenitic stainless steels.
Austenitic stainless steels have corrosions resistance throughout the fastener due to their chemical composition and are non-magnetic (i.e. why they are very useful in EV applications where alloy steels may have been used prior).
Martensitic is common for producers of pumps, turbines and valves, but do not have the corrosion resistant properties of Austenitic.
Ferritic steels have much of the corrosion resistance of Austenitic and actually have extra resistances against things like Chlorine, but they are magnetic, whereas Austenitic are not.
The flow chart then proceeds to stainless steel grade (i.e. A1, A2, A3, A4, or A5). These grades denote the chemical composition of the fastener, with higher grades providing greater corrosion resistance. (I will come back to this topic in a later article as well)
Finally the chart ends with those property classes (i.e. -50, -70, -80 and so forth), which indicate the mechanical properties of the stainless steel.
Here is a great free resource for those of you interested in the chemical and mechanical data of these stainless steels: https://www.rodacciai.com/normeetabelle.php?pid=37
APPROACHING BREAKING POINT!
I think we’ve reached a good place to stop for today. I know tables and graphs are not for everyone.
So I’ll dig into those tables and graphs a little more and break them down later in this series.
So here's what to expect next:
I’ll begin digging into crossovers in the next couple blogs, then we will dig into how the chemical compositions affect the stainless steels, and then get nerdy on some mechanical properties data!
About the author: London Penland, ex-teacher, tutor and educational non-profit leader and current business development director for Eurolink Fastener Supply Service and Social Chair/Educational Director for Young Fastener Professionals, empowers sales reps, purchasing agents and sourcing agents with researched industry-specific educational videos and articles. Click here https://eurolinkfss.com/vlog/ to see all of London’s VLOGs and gain access to download his lesson plans.