Tool Steel Knowledge needed

[acein]

When you purchase a tool steel such as 4340 what is the typical hardness off the shelf?  I guess what I am asking is what state does the metal come out of the manufacturing process in?  Is it allowed to cool slowly?  Any thoughts or ideas?

 

[M3F]

I could be wrong but I believe the only way to know for sure is to request the data sheet from the provider you bought it from.

[Frosty]

Steel is typically sold annealed, full soft. To know for sure, ask the seller or manufacturer.

Frosty The Lucky.

[acein]

Thanks for the info!

[patrick]

Many grades are sold "hot rolled" which may or may not be fully soft. 4340 is not really a tool steel by industrial standards, but it is quite hardenable. Most likely that grade would be sold either in the fully annealed condition or the pre-hardened condition. In this condition the material has been quenched and tempered, but the tempering temperature used is high enough to get something like 30 HRc. 4140 can also be found in this condition. These two grades are most often NOT used at very high hardness. Rather a lower hardness/higher toughness is desired. At HRc 30, the material is hard enough for many applications but can still be machined.

Other tool steels like 01, A2, D2, M2 etc are normally sold in the fully annealed condition because they are used at much high hardness and machining them at such a high hardness is very difficult and time consuming.

 

[JHCC]

Which equals expensive. 

[acein]

Patrick, thanks for the information.  I have read online that I can harden 4340 up to 60HRC.  Some say I can get 45 HRC with quenching, Then flame harden up to 60.  Do you think this is achievable?  

[swedefiddle]

4340 is called 'Alloy Steel', not Tool Steel.

[Nobody Special]

Well, I picked up a copy of The New American Machinist's Handbook today, new to me (copyright 1955) that looks like 4340 (H?) maxes out at about 60, but in the brief bit I've had to look through it, it seemed to indicate that it wasn't the normal heat treat, and that to get that hard you would probably nitride the steel, which if I recall, involves exposing the hot metal to ammonia gas to case harden it (Theophilus much?) . That seems worth a buck from the library's book sale.

[Steve Sells]

not sure how a flame hardening would get it from 45 quenched to 60, please explain

[acein]

Steve, are you really asking me to explain something I am asking about?

[acein]

Thanks for the reply Swedefiddle.  Yes I can't rename the topic.  4340 is a heat treatable low alloy steal containing Nickel, Chromium, and Molybdenum.  The steel is supposed to have great fatigue strength over time.  It is also supposed to max out around 60 HRC. 

I miss quoted earlier when I said Flame hardening.  Being as that I don't know what xxx xxxx I am talking about and came here for help.  What I should have stated (thanks Steve for being so helpful, yes that is sarcastic) is Flame hardening can get up to 50 and Nitriding can get you 60.

This is taken from Techsteel.net:

After tempering, flame or induction hardening will produce material with Rc 50, while nitriding will produce Rc 60.

[Frosty]

Seeing as you don't know diddly about the craft you might want to leave the sarcasm off the forum. When a published author blacksmith asks you for clarification of something you said, a sarcastic response will just get you cut off from his and other people's help. Worse Steve is an Iforge admin. and someone to stay on the good side.

How about if you don't know the answer just say you don't know? 

Frosty The Lucky.

[BillyBones]

I have a question, what are you planning on doing with this peice of 4340? 

If you are planning on forging it, it really does not matter if it is annealed or not. 

[gewoon ik]

To be honest. I get the response of acein. And also to be honest, Steve is not always the most helpfull guy around here. 

Yes he knows a lot, and yes if you have patience to google up the old treats, you find a lot of info he shared. But half the old threats are unfortunalty unreadable because of missing posts, missing pictures, ... (i know a lot of fora has the same problem, 2 or 3 times a major update in 10+ years and you end up with this kind of mess unfortunatly). 

A direct link to his book might helping as well maybe (to buy, not to free read ).

Or to share again, because I know also almost nothing about this and might learn something. 

 

[Steve Sells]

The heat treat info is posted here free already, pinned partly in knife section, the rest in general heat treating, and book links are in the stores book section, and there is always using the inter library loan if you dont want to buy it.

I asked how flame hardening will make it harder than quench hardening, sorry if that hurt your feelings

[acein]

You didn’t hurt my feelings. I’m frustrated by your posts. This is how a conversation seems to go on iforgeiron. 
 

Me:

How do I get from here to their?

Reply1:

I went there once:

Reply2:

You used the wrong spelling for There!

Me:

Thanks you are right. It should be There. 
 

Wait three days…

Me:

So back to my original thought. How do I get from here to there?

Steve:

Its been posted here before.

Me: 

Thanks I have been trying to search this cryptic forum to no avail. Haha the instructions to use google search for your topic and iforge yielded no usable results. By the way the info you provided doesn’t answer my question. 
 

Me:

How do I get from here to there?

Steve and frosty, you don’t have to reply to every post. Especially when you have nothing helpful to say. 
 

 

[Frosty]

I feel for you, you lost 4 years of in person schooling so your social development is way behind the curve as your general education. The pandemic affected everybody, you're not special.

Steve simply asked for clarification of a statement you made with a direct question. He didn't dress it up in some manner to suit the way you think people should talk to you. So YOU responded sarcastically. 

Nobody expects you to lick boots or beg for information but we've been at this a long time and you at least have to be polite. Steve and I were in no way discourteous, he simply asked for a clarification. I did indeed call you on what a lousy way it is to get what you want by being a snide sarcastic whiner. 

You are a guest on Iforge, I really enjoy helping folks by passing on what I've learned. However, it is a GIFT I OFFER FREELY, giving me a hard time because I didn't word a reply to suit you just puts you on my disregard list. 

I'll not bother you again.

[Buzzkill]

Sorry guys,  I'm with acein on this one.  He's been asking about hardening of 4340 and how to maximize the hardness of it.  He then asked if a specific sequence of techniques/processes would result in the maximum hardness, and instead of anyone actually answering the question he was asked how that would work.  That is not helpful at all.

He never stated it was a FACT that a process would result in a certain hardness.  He ASKED if the hardness was achievable with that technique.

Glenn specifically asked us to be respectful of newcomers.  I can't fault them for becoming defensive and sarcastic when their questions are met with responses that could certainly be interpreted as obnoxious even if they weren't intended that way.  There seems to be a return to excessive curmudgeonly responses lately.

For the record, the pinned heat treatment thread does NOT cover flame hardening (at least I didn't see it), so implying that his answer is contained in that location is disingenuous at best.

Why is it so hard to just answer the question if you know it, or link to a previous post that has the answer?  If you don't know the answer then why bother responding in an antagonistic manner?

 

[Steve Sells]

There is nothing about flame hardening, just quench hardening mainly because I dont know anything about flame hardening. so I asked, My pinned post does explain how hardening happens, so changing the method of how we trap carbon in the iron matrix does not make more carbon appear, either its there in the first place or it isnt, so unless other things are added as in a surface treatment of more carbon or nitriding, then as quenched is as hard as it is going to get which iirc was also covered in the pinned post

[acein]

Duly noted. Sarcasm in response to Snide remark, bad. Calling into question someone’s intelligence because of sarcasm, perfectly acceptable. Threatening to ban someone because Steve doesn’t like sarcasm, good  
 

Moving on…

The topic at hand is heat treating 4340. To answer Billy’s question I will not be forging it. I picked up a rem of the right size for power hammer dies. I had read that 4340 can be a good choice for that. However there is some question about whether 4340 can be hardened to where it should be for dies. 
 

From what I can tell 50Hrc would be acceptable for dies. This would mean I have to get the material to almost maximum hardness for 4340. 
 

I am looking for the best process to do this. 
 

Thank you for any help. 

[Steve Sells]

Since you are not used to heat treating, I honestly suggest hire it out, its not usually very costly, and you should get the best from your steel that way.  To maybe save a little money  allow them to HT with another batch rather than having to do your asap will save a little on cost

and for the record I never threatened to ban anyone nor, do I have a problem with sarcasm

[Nobody Special]

So, looking at flame hardening, it looks like it's a form of case hardening for mid-carbon steels by means of using an oxy-fuel mix to apply flame directly to the areas to be hardened followed by a water quench, either by submersion or by spraying it with water, creating a shallow layer of martensite. The idea is to leave the surface hard, but the core softer and more ductile especially on machine parts like rail surfaces or gears that benefit from wear resistance on the surface and softness underneath. It's also supposed to be a lot cheaper than heat treating the entire part.

Either that or nitriding would be something I wouldn't care to try without experience at home, especially nitriding since ammonia gas is corrosive, toxic, and displaces oxygen. I second either farming it out or getting help if you can find someone with more experience in heat treatment. You're considerably closer to the PNW Blacksmith Association meets than I am. Maybe one of them could point you in the right direction.

Also, I've seen dies made from 4340; they were mostly done by heating the entire part and using an oil quench, or sometimes water for particularly thick dies. Seemed to hold up fine.

[BillyBones]

Something i have noticed and hate about the internet. With forums, chat, comment sections, etc. you do not get the small inflections of voice, facial expressions, etc. that you get when talking in real life. You only get the words. And while you may say something in jest or humor another may take it as an insult or in anger becuase of not being able to read the person. You do not get the way a person speaks. Ok that is my 2 cents about that. 

Ok, so like many have said usually steel is sold annealed. So if you got a remnant from a machine shop, steel supplier what ever i would say that yes it is annealed and treat it as such. 

 

[acein]

Thank you Steve for your 2 cents

Billy, Thank you.  
Nobody Special,  when you say particularly thick dies would you consider 2x3x5 thick?