What steel to use for casting an anvil

A friend of mine is looking to cast a batch of anvils. These anvils will be professionally cast by a local foundry. He came to me to ask what steel to use. He had 7 suggestions for the steel.

4140
4340
6150
8630
8640
S7
H13

Of these, my suggestion would be either 8640 or H13. I would heat treat them to HRc 52 (50-55 range is probably acceptable). I'm pretty sure H13 would be the best steel but I'm guessing it is the most expensive and probably is not cost effective. I'm fairly confident on the target hardness but I'm anything but convinced of my decision on which alloy to use. My question to each of you is which steel would you use and why? Feel free to suggest other alloys not mentioned here.

I'll go ahead and give each of you my thoughts so you can confirm or reject my thought process. Feel free to jump in and correct me or add your own thoughts.
4140 - I haven't looked into this steel enough to make a decision
4340 - On the heat treatment chart, it starts at HRc 52 (HT at 400 F) and drops as you HT at higher temps. This leads to me to believe (just my guess) that it will have a finer grain structures than the steels that achieve HRc 52 at a higher tempering temp (such as 600 F). The smaller grains reduce the toughness when looking at two equivalent hardness steels.
6150 - I'm not sure what to expect with this steel
8630 - A good choice but this steel is already pretty tough so a little more carbon only helps the hardness. (I have not seen any datasheets on this steel)
8640 - (see 8630)
S7 - a good choice but very expensive and not as tough as H13
H13 - the best all around but very expensive

A little background on his project:
He is planning on making about 20 anvils at the minimum for his local blacksmith group. He will make more than that if their is enough people willing to commit. The target weight is 200-250 pounds each. His target price is about $800 per anvil. If he can hit the target price and get at least 20 people interested, he will go through with the project.

Thanks in advanced

I have a Nimba, and its 8640. And I would say, if anything, its a bit soft- which has to do with size and weight, as well- as I understand it, heat treating blocks up over 200 lbs gets to be very complicated, as the mass resists any quick quench, so the bigger the anvil, historically, the softer the anvil- which is one reason they developed the two piece anvils, with a tool steel plate forge welded to a wrought iron base, or later, the Fishers with a tool steel plate cast right into a cast iron base.

The nimbas are about Rockwell 50 or so.
Nimba Anvils – anvils made in the USA, double-bick blacksmith anvils, Italian-style anvils: Gladiator Anvil (450lbs), Centurion Anvil (260lbs), Titan Anvil (120lbs)

Now, Steve McGrew is starting to cast his Rhino Anvils at a foundry in Spokane, and he is using a similar alloy- he doesnt say exactly what it is, but I wouldnt be surprised at all if it wasnt 8640 as well, and he is getting about RC 52.
RHINO ANVILS

Steve Fontanini is using H13 for his anvils- I have never used one, but have heard good things about them.
Fontanini Anvil & t00l

I am dubious about the target price- I have met two of the three above mentioned anvil makers, and none of em are driving cadillacs- there is not much markup in any of them, and retail for the 250 lb range is $1250 to $1700.
I would be guessing that foundry costs alone are in the three to four bucks a pound range, then add in heat treating, and then milling and drilling- I am pretty sure all three of em have the tops milled flat, by a pretty decent sized mill, and I think the Pritchel holes are drilled after casting as well, while Hardy holes are cast in. But even then, Hardy holes may need broaching for accuracy. And then there is hand cleanup- every anvil from the foundry needs a fair amount of sanding and grinding, and the occasional patching as well- tig welding with a nickel rod, maybe, to fill pinholes.

Of course, there are pattern making costs, as well, and most foundries these days have pretty specific ways they want the patterns mounted, and often require that their patternmaker do it, for a price, of course.

I just hope he makes em pretty...

I'm starting to dabble in blacksmithing myself. . .so this topic caught my eye right off the bat.

$800 for a 200-250 lb. anvil is a fantastic price, but I don't know that he would be able to achieve a quality anvil at that price. . .I'm not trying to to say that he can't do it, but there is probably a reason why no one else is. Right now the current fair market price for a decent used anvile is between $3-$4/lb. putting a quality used anvil of the same size at about the price he is shooting for, but for a new anvil the price is about double that.

Check out this website. . .these anvils are made about a half hour from my house and are some of the best currently being made in the US. They (Nimba) use 8640 @ 50-52 Rc.

Nimba Anvils – anvils made in the USA, double-bick blacksmith anvils, Italian-style anvils: Gladiator Anvil (450lbs), Centurion Anvil (260lbs), Titan Anvil (120lbs)

The Centurion (260 lbs) goes for just over $1600.

I wish I had a heat treat book here at home, but I only have one at work so I could look at some of the tempering temperatures. I don't memorize most of them. . .but I work with 4140 and 4340 quite a bit so I know what they are for the hardness I'm normally shooting for. I think that 4140's temper temperature will probably be too low for an anvil and you could get localized soft spots from the surface of the anvil getting too hot; that may be a little unlikely. . .it would all depend on how large the piece getting worked is, how hot it is, and how long it is kept in contact with the anvil. . .is the work kept really hot and heated frequently ultimately putting more heat into the anvil or is it worked for a longer period of time between heats.

Things to think about and it sounds like you already have been thinking about some of them. . .good to see somebody thinking it through before just jumping right in.

Keep us posted on this and pic's of a final product would be really awesome!!!

Ries,
Thanks for the heads up on the anvil softness. I will pass the information on to my friend.

As far as cost goes, I'm pretty sure his plan is to sell the anvils unfinished. I'll ask him when I next talk to him. Also, these anvils are going to be more of a group buy instead of him making a profit. He is responsible for making the pattern, and the anvils will be cast and heat treated by the same company. I don't know if he can hit the $800 target price but he won't know until he gets the quote. For now he needs to pick a steel before he finds out if the project is even possible.

Atomicjoe23,
http://fordtoolsteels.com/pdf/LSS_4140-4142HT.pdf
This datasheet says that the hardness should be possible but I'm still hesitant for the exact reasons you mentioned.

I'll be glad to keep everyone posted on the progress of the project.

Ries said:

as I understand it, heat treating blocks up over 200 lbs gets to be very complicated, as the mass resists any quick quench, so the bigger the anvil, historically, the softer the anvil- which is one reason they developed the two piece anvils, with a tool steel plate forge welded to a wrought iron base, or later, the Fishers with a tool steel plate cast right into a cast iron base.

Click to expand...

Yes the quenching rate is critical.... For example with plain carbon steel you have to reduce the temperature from 700C to 500C in one second for the piece to end up hard....

An alloy steel like A6 the time frame is much larger and they do not need quenching and sections up to 4" thick will air harden when cooling...

I was the master toolmaker for Colonial Williamsburg,now retired. I made the patterns for their anvils,which both weighed 300#. They have been using one type since the 70's,with no noticeable damage to their tops yet. The other was an earlier type 5 legged anvil I finished just before retirement that is in the process of being cast and the tops ground for about $1500.00 each. I saw the first casting,not hardened or ground yet.

Both were made of 4140. The first was made by a foundry in Texas,but they went under,and the pattern was lost. Foolish of them to leave it there as it took me about 2 weeks to carve it and make it look hand forged.

In the old days an anvil was quenched under a waterfall. Great need for lots of water for rapidly cooling that mass of metal. I don't know how they quenched the Texas anvils,but they have been hard enough to stand up.

If your anvils cost $800.00 each,does that include hardening them and grinding their tops?

As I understand it, modern alloys often are not "heat treated" as such, in really big chunks like a 250 pound anvil- as RC99 said above, a block that big kind of tempers itself, as the mass holds heat so well that it tapers down the temp over a pretty long time.
Its true, that in England in the 1800's, they would use large bodies of water, or better, waterfalls or waterwheels, to quench, but they could get away with that because they were forge welding relatively thin strips of steel to wrought iron bodies- no waterfall in the world will cool a 500 pound block of solid tool steel fast enough- you get a steam layer right at the hot steel almost instantly, and then the steam stays the same temp for quite a while.

Fisher in New Jersey had a manmade waterfall in their factory, but, again, they were only quenching 1/2" or 3/4" of steel- the rest of the mass was cast iron, which they wanted to get cool, so it wouldnt affect the heat treat on the steel, but they werent actually hardening it much.

The new, all steel anvil is relatively recent- I believe the Germans (Peddinghaus) and the Swedes (Kohlswa) have been forging solid one piece steel anvils for 80 year or so, maybe a bit longer, but the steel technology, and forging presses big enough to do this, are relatively recent innovations. The one piece cast steel anvils are even newer- 40 or 50 years, probably.
And modern steel formulations are miles ahead of what was available 100 years ago, meaning anvil makers can have a really good idea of how to heat treat a solid block efficiently and get the hardness they want, where they want.
No waterfall building is needed. Or firehoses, as some have proposed- which, again, would probably result in a steam blanket right away.

Grant Sarver used 4140 for all his hammer tools, and they are great- hard enough, but not too hard, tough, and heat resistant- you can beat on red hot material all day with it, and it wont deform.

The kind of steel to use for casting? Molten steel. Cold steel simply doesn't pour very well.

Sorry, I couldn't resist!

6150 would be my choice. Has great impact resistance. Have made many chisel bits from this material for oilfield work.

my anvil is a section of railroad track. would anybody know what its made of and how hard it is?

dian said:

my anvil is a section of railroad track. would anybody know what its made of and how hard it is?

Click to expand...

I also have a section of railroad track to use as an interim anvil, but I have no idea what it is made of or how hard it is. . .I'll see if I can find some info.

Comparison of anvil steel properties:

http://www.hybridburners.com/documents/M-Main-on-anvil-steel.pdf

I can't say for sure since I'm not the one making the anvils, but I'm guessing that all of the finishing work (grinding, machining, flattening, etc.) will be done by each individual. The cost would include the heat treatment. That said, from what everyone is saying it doesn't look like the price will be doable. He hasn't gotten the quote yet. $800 was his target price for the project to be a go.

I'll take another look at 4140 and 6150. I don't know much about them.

As far as railroad track goes, it was originally cast iron. Later it became steel. As to which alloy will depend on how old it is and who the manufacturer is. That's about all I know. If someone does find a list of the alloys used in railroad tracks, please let me know.

Glabe, that is an awesome table!

Thanks everyone for the help.

railroad track steel: one source says 1.2242 59crv4.

i also found this. (cannot copy a pdf in here.)

Chemische Zusammensetzung und mechanische Werte: ThyssenKrupp GfT Gleistechnik GmbH

now if i only knew how to translate hbw into hrc.

Gabe Newell said:

Comparison of anvil steel properties:

http://www.hybridburners.com/documents/M-Main-on-anvil-steel.pdf

Click to expand...

Thanks for the chart!!!

Ries said:

Grant Sarver used 4140 for all his hammer tools, and they are great- hard enough, but not too hard, tough, and heat resistant- you can beat on red hot material all day with it, and it wont deform.

Click to expand...

Grant and I discussed forging smaller anvils than are being talked about here. He felt in anvil thicknesses 4140 would not harden enough. 4340 however would harden deeply enough in the heavier sections. I have forged 2 42lb stake anvils from 4340 and they were around 50rc as forged.

Rail steel:

Rail Steels :: KEY to METALS Article

Per U.S. Steel's book, "Making, Shaping and Treating of Steel" common rail steel has .65-.80 carbon
and .70-1.0 manganese. This makes it close to SAE 1070 carbon steel. It is commonly used as- rolled.
There are also special grades with some alloy content and some grades have the head area hardened.

Pattnmaker,
Thanks for the heads up. If an anvil made out of 4340 that weighs 42lb is only getting to 50 HRc than 4340 probably won't work. My friend is aiming for a minimum 50 HRc. Do you think it is possible that the low hardness came from an inadequate quench? The anvil chart by Gabe shows Emerson anvils being made from 4140.

kenh,
Thanks for the link. I never realized "steels" with 0.04%C were still being used.

swall,
It's interesting that the U.S Steel's handbook differs from the article posted by kenh. I guess the U.S. Steel's handbook is talking about overall tendancies?