Telling the difference between D2 and A2 steel?

W

Whatsup

Joined
Aug 25, 2023
Messages
27
Hi there,
My first post, so cheers to everyone :). I got a bar of eighter D2 or A2 steel - I just don't know. Is there a way to tell which one it is? It's not magnetic. I would appreciate some help. Though I am not sure if one can tell the difference at all. It might be impossible to answer... Let's see! :)
thanks!
 
I am positive it's eighter A2 or D2.
I just used a stronger magnet and I can confirm that it's magnetic. I also dropped water on it. Some drops already dried up, but no corrosion. Just some dark rings/patina kind of thing
 
This is what it looks like after vinegar and water... I lack the experience to be able to tell the difference between D2 an A2. I am leaning strongly towards D2 though. What do you guy's think?

123.jpg
 
Hi there, welcome to the forum from another newbie,
I think you might be analysing the mill scale not the steel, grind the scale off and then do the test.
 
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Whatsup said:
I am positive it's eighter A2 or D2.
I just used a stronger magnet and I can confirm that it's magnetic. I also dropped water on it. Some drops already dried up, but no corrosion. Just some dark rings/patina kind of thing
Click to expand...
It does not matter how strong magnet you use .If metal is no magnetic even strongest magnet on earth will not work .
 
If you do your own heat treating, harden a small coupon for A2 on the lower end like 1725’f, and check the hardness. The D2 should under harden at that temperature.

Hoss
 
N Natlek : It's barely magnetic. Only a stronger magnet made me notice any magnetic force.

I thought D2, although fairly stainless, takes a patina relatively quickly compared to other stainless steels. Especially with acid. D2 should be very tough to work, even when annealed - notably harder then A2. I am afraid that's hard to judge though!

D DevinT : Unfortunately I don't do my own heat treating :(

I guess there's no way to tell which of the two steels it is...
 
I agree with Larrin. It isn't worth the worry since they are vastly different in HT.

As an alternative, cut off a 2" long piece and send it to a friend who has a HT oven. Have him do what Devin suggested and test the hardness. It would be even better if tested against a known sample of A2 and D2.
 
Funny story.

The other day I saw an ad from a guy that was selling tool steel, including grade 19573 (Czech designation) - so D2, which I wanted (just because).
I asked the guy if he still had this specific steel, because that is what I was interested in - he says "I have tons of it, come and take your pick".

So I went there, met the man. He showed me a pile of steel, round stock, bar stock, all kinds, unmarked. I asked "where is the 19573?". To which he says "ah, I do not know, I'd have to figure it out, blah blah."
Turns out, he had lots of leftovers of various steels, but the best parts were already picked out by the big fish, and he had no idea about the grade of the steel he still had.

Since I was there already, I bought some of the nicer looking pieces of unknown steel, and when I got home I found a company that could do X-ray analysis of metals for you.

I sent them an email asking if they could do some processing of samples for me. They said "sure". I sent them 5 samples from the pieces I bought. Based on their website the analysis should have been about $20.

After some urgencies they sent me the analysis back, so after that I knew what I purchased (which was some mild steel, some steel for surface hardening, some O-1). Great. But when I asked them (repeatedly, mind) for an invoice, I got no response. So essentially they did it for free. You do not encounter a situation when you WANT to pay for something, but you do not get a chance to do that.

So my takeaway, based on statistical analysis of 1 sample is: send some samples of the steel to a company that can do X-rays, and they will do it for free!
 
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