FTM 162: What is A36 Threaded Rod

Fastener Training Minute 162: What is A36 threaded rod

This edition of the Fastener Training Minute with Carmen Vertullo was originally published March 19, 2021 as “What is A36 threaded rod” during episode 162 of Fully Threaded Radio.

Well, hi everyone. This is Carmen Vertullo with your Fastener Training Minute coming to you from the Fastener Training Institute and AIM Testing Laboratory in beautiful El Cajon California.

As is often the case, today’s Fastener Training Minute comes from an email question from one of our many listeners, and that email question had to do with the material number or letter or designation, (whatever you like to call it), A36. What is that? Well, it should mean something to us Fastener folks, but more importantly it means something to the Steel Community, and when I come back, I’ll tell you why you should know what A36 means when you hear it in the context of a fastener material designation.

Today’s topic is A36. I recently received an email from a listener who asked: “I have a request for quote for A36 threaded Rod. What is that?” Well often times when we hear the word A36 in the steel Community, we think of low carbon steel, relatively low strength and probably the most common type of Steel. The ASTM A36 specification usually applies to rods and plates and bars. We hardly ever see it properly used in the context of a fastener requirement because when we use the term A36 relating to fasteners, what we should be talking about is ASTM F1554 grade A36.

Which happens to be about the same exact material as A36 steel rod, plate or bar. However without the ASTM F1554 on it, there really is no such thing as A36 threaded rod. In the old days we had ASTM A307 which is another specification for low carbon low strength steel fasteners. We had a Grade C in there, which was threaded rod very equal to A36. By the way, the A36 tensile strength is about 60 KSI. On the very low-end, it’s allowed to be as low as 58 KSI but you hardly ever see a bar of A36 that’s lower than 60 KSI tensile strength, and that’s where ASTM a307 starts.

A36 does have an interesting property about it in that it is 36 KSI yield strength. In ASTM F1554 the grade A36 literally means it’s 36 KSI yield strength. The yield strength being that point where the fastener or the material stretches and permanently deforms. It won’t go back to the way it was but it doesn’t break. The tensile strength or the ultimate tensile strength is the strength at which the steel would break. So now whenever you hear A36, you’ll know that it’s talking about steel, unless it’s accompanied by ASTM F1554 grade A36.

Now the quandary is, many end-users just don’t know what they’re talking about when they ask for A36 threaded Rod. We see it often from the construction and structural communities. However, if you look at the material test report that comes with your low strength threaded rod (that is the mill test report), chances are very good that it will indicate the raw material meets the requirements of ASTM A36 and that should satisfy any end-user that asks or A36 threaded rod.

Well now, you know, all there is to know about one of the simpler topics in fastenerdom: A36.

This has been Carmen Vertullo with the Fastener Training Minute. Thanks for listening.

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