I've seen in a few threads people chiming in on metals used in certain applications, so I thought this would be a good place to throw this out:

A friend has a 6.0L Ford that blew a head gasket & he's shopping studs from a couple companies. 1 uses 300M, another uses H11. One is more $ than the other, but quality is his concern. I looked both up & see 300M is rated to a higher KSI but I know that's not the only factor. I just don't know enough to weigh the other properties against each other.

So, there it is - Which is better for the application? Pros & cons? What would you use if you spec'd them, ideally & from a value (strength/price) standpoint? Get as in-depth technical as you want just please try to include some "lay-people" talk so us common folk can make some sense of it too.

Thanks in advance :ro)

I've seen in a few threads people chiming in on metals used in certain applications, so I thought this would be a good place to throw this out:

A friend has a 6.0L Ford that blew a head gasket & he's shopping studs from a couple companies. 1 uses 300M, another uses H11. One is more $ than the other, but quality is his concern. I looked both up & see 300M is rated to a higher KSI but I know that's not the only factor. I just don't know enough to weigh the other properties against each other.

So, there it is - Which is better for the application? Pros & cons? What would you use if you spec'd them, ideally & from a value (strength/price) standpoint? Get as in-depth technical as you want just please try to include some "lay-people" talk so us common folk can make some sense of it too.

Thanks in advance :ro)


Send a PM to Opie.

This is what he does for a living. IIRC there is a huge difference in Yield strength between the two alloys. But for this application, I have no knowlege on what would work better.

The major point is, you can't say for sure without knowing MUCH more than just the alloy content.

How it's formed and heat treated (and the condition of the starting stock) can have EVERYTHING to do with how they perform.

So the exact answer is, only knowing what you said above, is that there is no answer.

Both can be made strong enough to make good studs that are many times stronger than stock.

But never forget that if the head design is marginal in the first place, you could be applying a very expensive band-aid to some other inherent problem (like needing more head bolts altogether). Studs won't solve that problem.



Oh yeah, and screw you, Juice, for not giving me any props.

Oh yeah, and screw you, Juice, for not giving me any props.

Matt, you make your point as delicately as ever):h

Dieselspeed, Matt can also supply you with information in this regard.

please send him a PM first, then to Opie . Then send Matt a PM note of thanks for his help and CC it to me so he stops busting my chops Eh?

Cryoed' Kolene Bath, Hard Anodized, Machined from billet stock then treated how?

Tensile VS Yield strength, and in what percentages?

Thanks!

I can get more info tomorrow at work, but here's something to chew on in the meantime.

H-11 main application: a die steel for hot work.
Composition:
Carbon: 0.4%
Chrome: 5.0%
Manganese: 0.3%
Molybdenum: 1.3%
Silicon: 0.9%
Vanadium 0.5%

Quenched and tempered, you can get:
Ultimate tensile strength: 221 ksi
Yield strength: 189 ksi
Eleongation: 38%
Reduction in area: 11%

300M is a variant of 4340, a mutlipurpose high strength steel. You would expect to see this used at somewhat lower temperatures than H11 would take. The high chrome content of H11 allows the extended high temp use.

Composition:
Carbon: 0.42%
Chrome: 0.8%
Manganese: 0.75%
Molybdenum: 0.4%
Silicon: 1.65% (this is the variation; higher than 4340)
Vanadium: 0.07%
Nickel: 1.80%

Heat treated, you can get:
Ultimate tensile strength: 298 ksi
Yield strength: 251 ksi
Elongation: 11%
Reduction in area: 34%

Both of these materials are very strong. And before you jump all over the 300M due to its high yield strength, just remember that to yield the "weaker" H11, a 1/2" bolt would require a load of 37,000 lb. and would not break until it had stretched 38% more than its original length by a 44,000 lb force.

Either should beat stock studs by a frickin' country mile.

Ok, got some room-temperature data, courtesy of the ASM handbook.

Again, both of these alloys are strong and tough. The one difference that you can't see in the tables in the effect of temperature. The high Cr content of H11 (and H11 "mod") allows it to maintain hardness at high temps; there isn't a huge drop (~10%) in properties from room temp to 950F. However, over that same range, 300M would lose roughly 50% of its strength.

For head bolts, that's probably not an issue, but it's the standout difference between them.

I'll try again for those who might not have Excel. Resize the pop-up window to full screen to view it best.

So... 300M would be stronger @ room temp, but it seems like H11 is the better when being exposed to heat, right? What's the difference in tensile strength vs. yield strength, & which is going to be a bigger factor here? Matt & Juice - thank you PM's on the way ):h

Any other thoughts?

I'd go with H-11. Its got more chrome. We all know how much better something is when its Chromed :bling: Basic ghetto metalurgy states that if something is shinny its much better ):h

I'd go with H-11. Its got more chrome. We all know how much better something is when its Chromed :bling: Basic ghetto metalurgy states that if something is shinny its much better ):h
:funnypost I'm saving up for some H-11 Grillz - figure that's all I need for a multi-platinum rap album... Plus I can pretend I'm the bionic man when I eat dinner

Ok then smarty pants. I noticed ARP's studs are made from 8740. How does this material compare to the 2 mentioned above?

Smartypants yourself, John!!!

ARP is saying that 8740 would have ultimate tensile strengths in the 180-220 ksi range. Other sources say 105 ksi yield and 125 ksi ultimate. None of these listed the condition in which they were measured, so I'd kinda go with the ARP numbers for now. Tomorrow I can get more accurate info.

As for the previous question, go back and re-read. H11's properties only decrease ~10% in the ENTIRE range of room temp to 950F. So that means at 200F, you barely lose anything (a few %). With the 300M you'd lose a hair more, but at 200F the losses are not really significant in either.

So, for example, H11 would probably make a much better exhaust manifold stud than would 300M or 4340 because its properties hang in there better at high temps.

Make sense?

I thought ARP's were 300M's??? They were the company in question - maybe that's just for the 6.0L's?

ARP has at least a half dozen alloys (from mild to wild) available depending on the application.

Check out their website, there's plenty of info there. Some of the alloys have tradenames that are proprietary to ARP, so I don't believe you'll see "300M" in their list. One of their alloys may be close to 300M, or a slightly modded version.

Thanks for the PM! LOL, i laughed reading it! It was actually a tongue in cheek post by yours truly.

I'd go with H-11. Its got more chrome. We all know how much better something is when its Chromed :bling: Basic ghetto metalurgy states that if something is shinny its much better ):hchrome don't get you home:D ...thats an oldy, but goody:ro)

OK, I have some info for you on the 8740.

Actually I have data on 8640, which is a close brother. 8740 has .05% more Moly in it than 8640.

The overview is that 8740 behaves similarly to 4340, but isn't as hardenable in thicker sections, meaning when you quench them, the core is softer than the outside layers of the part. "Deep hardening" alloys like 300M exhibit excellent uniformity through the thickness when heat treating.

All that really means is that 8740 is better suited to small parts where deep hardening (and "deep" as in *inches deep*) isn't all that important. Like head studs.

8740 nominal Composition:
Carbon 0.4%
Chrome 0.5%
Manganese: 0.9%
Molybdenum: 0.25%
Silicon 0.25%
Nickel 0.55%

See table below for basic properties. I don't have any complete tables for 8740, so the data below is 8640. I would expect them to be pretty close to each other. Looks like an excellent steel alloy.

And for anyone wishing to learn more, check out basic stress-strain relationships here: http://en.wikipedia.org/wiki/Stress-strain_curve

I almost followed that wikipedia link but figured I should ask first - am I going to end up with even more questions for you?

am I going to end up with even more questions for you?

There's #1 ):h

Many people get confused on the difference between yield stress and ultimate tensile strength. For many applications, yield strength is what you need to know, because the intent for most parts is to stretch but not deform permanently.

Another thing to consider is thead contruction. How are the threads made? Turned, Rolled or Ground? Rolled is what you want. The other methods of thread forming interupt the grain stucture of the steel. Where rolling actually forms the grain stucture to the shape of the threads. Much stronger. I know ARP rolles their threads. Others I do not know.

nwpadmax - to make sure I'm understanding correctly - yield strength is how much give it has (elasticity) before it it wont' revert to its original shape anymore; tensile strength is the point where it breaks?

JOHNBOY - is thread construction generally a cause of failure?

nwpadmax - to make sure I'm understanding correctly - yield strength is how much give it has (elasticity) before it it wont' revert to its original shape anymore; tensile strength is the point where it breaks?

JOHNBOY - is thread construction generally a cause of failure?


I can't speak for a head stud in particular, but a thread will generally fail in the root of the thread due to 1. being the smaller cross section, and 2. depending on the size of the root radius, there can be a major notch factor.

A good way to combat this is, where the thread runs out, a large radiused undercut with the minor being smaller than the root of the thread can be cut into the bolt or stud. This will allow the bolt to stretch a bit more before the bolt ends up pulling apart at the thread root. There is many other things that can be done to help with thread strength like thread shape, shot peening, non matching pitches, and so on. I could go on for a while on thread strength, as that is one of our specialties at work, but typing isn't one of my strengths.

DieselSpeed, you have it correct.

Johnboy and Dmaxlover are correct. Rolled threads are generally considered to be the best method, and yes, stud failure can happen in the root of the thread.

BUT....

I've never heard or seen a Dmax stud fail. Have you heard of aftermarket 6.0 studs failing? Personally I think they're probably all overkill unless you're running wicked boost / drugs / etc.

I think the thing here that will help is "impact resistance". Being an actual Toolmaker who trouble shoots failed tools and rebuilds them to serve an extreme duty life cycle (most run 15 millon to 50 millon cycles under 250-550 tons), this is were it comes in at. The threads need to be cut with no sharp edges down in the bottom to give them the chance not to fail there (fracture or stretch area). H-13 is a higher grade than H-11 and will be much more suitable of a steel for this application (look for around 48-49 RC on the C scale after heat treating). Still there is another that is superior though.

Define "much more suitable". What you said SD is vague at best.

Higher grade, better quality, better impact resistance, higher resistance to fatigue (expecially in heat induced areas). D2 is superior in this area but can be quite brittle if stretching is allowed to start. There is some new stuff out now however that I am working with that will probably be the kitty cats meow.

That's a bunch of non-technical buzzwords. Gimme something to go on.

I think the thing here that will help is "impact resistance". Being an actual Toolmaker who trouble shoots failed tools and rebuilds them to serve an extreme duty life cycle (most run 15 millon to 50 millon cycles under 250-550 tons), this is were it comes in at. The threads need to be cut with no sharp edges down in the bottom to give them the chance not to fail there (fracture or stretch area). H-13 is a higher grade than H-11 and will be much more suitable of a steel for this application (look for around 48-49 RC on the C scale after heat treating). Still there is another that is superior though.

SD
Did you click on my screen name and look at my occupation? Your not the only Tool maker on this board.:) I am a Journeyman Tool and Die Maker. Yes using a root raduis near or at max spec will help. But it does not change the fact the tool is cutting across the the grain. Which provides a clear path for shear. To those that might be lost let me explain it this way. Most tool steels have a directional grain flow like wood. In round bar it flows the length. When you cut a thread you cut across the grain. Just like wood it is much easier to split with the grain then across it. Rolling a thread froms the grain because it does not cut the steel rather it compresses it into the thread shape. The grain is shaped to flow with the thread form. Like the way grain flows around a knot hole in board. The grain is not parallel to the load force. Where in a cut thread it is.
This makes a noticable difference in durabilty.

As far as H13 or H11 goes I really would rather use a 8000 series steel. H series steels are strong no doubt. When you harden H13 it moves a lot compared to say 8620. But in the hardness range you list threads can still be cut into it. Truth is I like turning hardened H13 better then soft not as gummy and man what a nice looking finished part you get! But for something like a head stud I pefer 8620.

I think that nwpadmax hit it on the head when said all are more then enough for the job. I also agree that head studs on a Ford 6.0 are just a bandaid for a pi$$ poor Intertrashional design.

Like grandpa said " The only thing International made worth a darn was $hit spreader and they won't stand behind that either":muahaha:

...I think that nwpadmax hit it on the head when said all are more then enough for the job. I also agree that head studs on a Ford 6.0 are just a bandaid for a pi$$ poor Intertrashional design.

Like grandpa said " The only thing International made worth a darn was $hit spreader and they won't stand behind that either":muahaha:
:funnypost I do agree - you don't have to be a metallurgist or toolmaker to see that's just one of many design flaws - This thread is very informative though, and helpful in the interest of making the best of a bad situation for our misguided Ford friends :ro)

I build stack molds as well as analize tool failures. Been trouble shooting them now since '88' (I was a Journeyman then). Hard turning threads isn't my idea of fun. H-11 will work (as well as other tool steels), however if I did an H series it would be H-13. Any good tool steel will move in heat treat. It depends how much from how it is set up in the furnace and how it is set up in draw (I do this too). There is still a better tool steel available for this application (if it's even needed).

So I'm wondering before the debate on what type of tool steel's ideal really gets going, why use a tool steel of any type to begin with? What quality or qualities make it a "tool" grade?

Tool steel definitions

Any high-carbon or alloy steel used to make a cutting tool for machining and forming metals and for metal-casting dies.

A generic term applied to a wide range of steels, both carbon and alloy, which are suitable for various types of cutting tools, press tools, dies, etc.

High carbon steel used for making cutting tools.

Any combination of carbon and alloy components.The combination will depend on the requirements for the tool.

alloy steel that is suitable for making tools; is hard a tough and can retain a cutting edge

Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinct toughness, resistance to abrasion, their ability to hold a cutting edge and/or their resistance to deformation at elevated temperature (red-hardness).

IMO the thread is what is not important in a head stud. This assuming the minor of the thread isn't the smallest cross-section of the stud. By the time the stud is stretched enough to snap at the thread, the head gasket is all ready gone.

IMO the thread is what is not important in a head stud. This assuming the minor of the thread isn't the smallest cross-section of the stud. By the time the stud is stretched enough to snap at the thread, the head gasket is all ready gone.


This is true. So is the statment from JohnBoy about the rolled threads (10-20% stronger). The fact of the matter is most all headstud manufactures have studs strong enough that most of us if not all will never get to the failure point with. The crank will probably go out the bottom first (provided the other components are up to the challenge). I made some studs out of some Dievar (premium grade of H-13 as my choice) as a personal preferance after dealing with multiple tool failures (from impact and streching) with lesser grades in the tooling industry that was remedied by this stuff. Just my personal experience. We even went as far as Meta-Laxing the components to get cycle life up with the lesser grade tool steels. We were forced to find another alternative. Again, just my experience and preferance.

Certainly no expert on bolts or metallurgy, but...

Not sure breaking headstuds is a big issue. I guess the property to look for is resistance to stretching after huge numbers of cycles. The thread to be concerned about are probably the ones in the block, not the ones on the studs.

Heat-treated 300M seems to resist deforming after many cycles, and is often used in shafts that are subject to repeated torsional loads with good results. Would it be a good choice for bolts? Dunno.

Would it be a good choice for bolts? Dunno.

Sure. I see nothing in the metallurgy of 4340 or 4340 mod (300M) that would preclude its use.

For studs I would use one of the newer, high tech, nickel alloys.

625 comes to mind. hint, hint.

It would be hands down better than H-11, 4340, etc.

Don~

For studs I would use one of the newer, high tech, nickel alloys.

625 comes to mind. hint, hint.

It would be hands down better than H-11, 4340, etc.

Don~


I see all the super properties of the nickel based alloys on the ARP website, some of which seem to be a bit high compared to what I see in the handbooks.

But even so, can anyone in the diesel field prove that they need a head stud with 260 ksi yield over an alloy steel with 220 ksi?

I don't hear of people snapping head studs...are they?

Lastly, the marketing mumbo jumbo raves about tensile strengths, which are an indicator....but unless you want your studs permanently stretching, we need to look at yield strengths, and some of the Inconels ain't that great at that.

School me here if I'm wrong, but I don't see the need.

Ok....moved my OT posts and I appologize for starting the discussion in the first place here. I also appreciate you guys puting up with it and answering my questions. :) Here is the new thread http://www.dieselplace.com/forum/showthread.php?t=121845

Now back on topic :)

I see all the super properties of the nickel based alloys on the ARP website, some of which seem to be a bit high compared to what I see in the handbooks.

But even so, can anyone in the diesel field prove that they need a head stud with 260 ksi yield over an alloy steel with 220 ksi?

I don't hear of people snapping head studs...are they?

Lastly, the marketing mumbo jumbo raves about tensile strengths, which are an indicator....but unless you want your studs permanently stretching, we need to look at yield strengths, and some of the Inconels ain't that great at that.

School me here if I'm wrong, but I don't see the need.

Well it depends on what one is trying to do.

On the Cummins side, 12mm is the factory size head stud. Some drill and thread the block for 14mm. Some circles disagree with this practice.


In order to increase the clamp load, the higher strength material has been employed. We can TQ the nickel alloys to 150 and more ft lbs. VS. 96ft lbs ( 75% yield )-122 ft lbs ( theroetical 100% yield ) on the carbon steels.

If you used a 14mm stud, 8740 or similar would be fine and dandy, but some feel the block stud boss's will be compromized. Myself included.

With overall material cost being a basic toss up to make a custom set of 1 off studs, I say go for the stronger material so you can increase the TQ if needed.

Don-

I totally follow your logic, but I still have a couple things that don't make sense to me.

Say we choose 300M to make a stud. This is garden-variety tool steel metallurgy and anyone skilled in the art should be able to make this with yields in the 240ksi range.

Now, say you choose Carpenter's Custom Age 625 Plus (which is also one alloy that ARP lists). If you do garden-variety metallurgy here, you can end up with mediocre properties, with yields as low as 100-140 ksi. Not impressive at all. However, if you carry out the cold work + aging and do it just right, the properties take a dramatic jump to 260 ksi. Very strong, but not out-the-wazoo better than our reference 300M.

Point is to the readers here, the Ni alloys have excellent properties but must be carefully treated in order to get that. You can't just run out and get any old piece of 625 and make a great stud from it. If I were doing this, I'd want a pedigree on the incoming material, test it for structure, and then do some heat treat experiments to verify that I was getting the aging just right for the section thickness, etc., and then I'd yank some tensile bars to prove that my process would be stable within and between lots.

Don, if there's other Ni alloys I should be looking at as better examples, let me know. 300 ksi YS with reasonable ductilities are rare birds.

Do you know the Charpy notch numbers of 300M @ 240KSI.

I thought the sensitivity of 300M to notch toughness tests was getting high @ 240KSI. Add some heat to the equation and?????

625 can be worked to 260 KSI tensile and 220-230 yield and have stupid good notch toughness, even at elevated temps.

Turning 625 is not to bad. Most people make the mistake of to high a suface footage. But I wonder what it is like to thread roll? I am betting that would be fun.:rolleyes:

Don

Over torquing with stronger studs seem like a bandage to me. It sounds like the distance between the studs is to great. Adding more studs seems like the best answer. But I am betting that is not possible or you would already done it. Is the head strong enough to use the added torque? Or will it still give to the high pressures.

I've seen in a few threads people chiming in on metals used in certain applications, so I thought this would be a good place to throw this out:

A friend has a 6.0L Ford that blew a head gasket & he's shopping studs from a couple companies. 1 uses 300M, another uses H11. One is more $ than the other, but quality is his concern. I looked both up & see 300M is rated to a higher KSI but I know that's not the only factor. I just don't know enough to weigh the other properties against each other.

So, there it is - Which is better for the application? Pros & cons? What would you use if you spec'd them, ideally & from a value (strength/price) standpoint? Get as in-depth technical as you want just please try to include some "lay-people" talk so us common folk can make some sense of it too.

Thanks in advance :ro)
the only kind of studs he should be looking at ar ARP. they are the only way to go for in engine bolts.
i didnt read the whole thread but if the head is leaking gas of fluid the maybe o-ring the heads and put copper wire gaskets in there. its what i had to do in my mustang to handel the boost.