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4140HT steel

10 fingers

10 fingers

Hot Rolled
Joined
Mar 9, 2003
Location
Vermont
Also known as, 4140 PH (pre hardened) HRC 27-32
My regional distributor historically sold resulfurized, round bar. Great tool life and surface finish. Distributor has switched to a mill suppling product with no free machining additive. Part quality is suffering. Struck out finding the former product elsewhere. Appealing for a domestic source for 4140HT with sulfur or lead additive. Bar size to 12"
 
Bobw's suggestion may be an alternative. In my case, I would prefer turning a harder material. Pre-hardened to 27-32 is useless, finishes improve dramatically if the stock is closer to 36-42 HRC or higher. There is one draw back from using leaded stock; it doesn't black oxide very well.
 
I used to use a hot rolled 4150 modified that was resulfurized Rc 28-32. Is such a material still available, and would it work for you? At the time I think it came from EMJ.
 
10 fingers said:
Also known as, 4140 PH (pre hardened) HRC 27-32
My regional distributor historically sold resulfurized, round bar. Great tool life and surface finish. Distributor has switched to a mill suppling product with no free machining additive. Part quality is suffering. Struck out finding the former product elsewhere. Appealing for a domestic source for 4140HT with sulfur or lead additive. Bar size to 12"
Click to expand...

I always bristle a little when they quote those numbers because I can literally count the number of times that it came in over HRC26 on the hand missing half of one finger.

It might help to know who your old supplier is in effort to not recommend them. Otherwise, just about everyone has had it for us, lately. I imagine that you and I use it for the same end results. Something I have done in the past when I chose/needed to be anal about the specific heat treat was to buy the less expensive bar stock and harden it myself. You might find that the cost works for you.

Lastly, the advice that the slightly harder material cuts better definitely correlates to my own experience, but you might want to look at your inserts just the same. I've never had some of the newer grades have any issue at all with the commonly typical range of PreHard. ( and we use it just about every single day )

Call if you want. Hope you're doing well.
 
Thanks for the feed back.

Zahnrad Kopf said:
I always bristle a little when they quote those numbers because I can literally count the number of times that it came in over HRC26 on the hand missing half of one finger.

It might help to know who your old supplier is in effort to not recommend them. Otherwise, just about everyone has had it for us, lately. I imagine that you and I use it for the same end results. Something I have done in the past when I chose/needed to be anal about the specific heat treat was to buy the less expensive bar stock and harden it myself. You might find that the cost works for you.

Lastly, the advice that the slightly harder material cuts better definitely correlates to my own experience, but you might want to look at your inserts just the same. I've never had some of the newer grades have any issue at all with the commonly typical range of PreHard. ( and we use it just about every single day )

Call if you want. Hope you're doing well.
Click to expand...

I had resisting elaborating to not complicate the question. Albeit PVD coatings, we are cutting with cobalt HSS not much different than 100 years ago. Material machineability is paramount. Especially with 100s of 12" dia 4 pitch parts. No margin for supplemental heat treat at those weights. Up until a year ago life was great using aforementioned 4140/50HT RS (resulfurized.) Was produced by a mill in France. Unable to find an equivalent material elsewhere.

Blue skies, -Don
 
10 fingers said:
Also known as, 4140 PH (pre hardened) HRC 27-32
My regional distributor historically sold resulfurized, round bar. Great tool life and surface finish. Distributor has switched to a mill suppling product with no free machining additive. Part quality is suffering. Struck out finding the former product elsewhere. Appealing for a domestic source for 4140HT with sulfur or lead additive. Bar size to 12"
Click to expand...

Making tough gears? LaSalle ETD150 is a 4142 doped with selenium. Elevated temp drawn, quenched & tempered. It WILL test 32Rc (30-34 limits, or call Wilson to get your tester fixed…). Machinability rating 75% of 1212 so plenty good with coated HSS. Find a dist thru Niagra – LaSalle. Or just google "ETD150 steel" and a link should show up.

2nd choice, Productigear in Chicago buys FX-Xtra from Finkl (same city) for tough ready to machine gear stock. I don’t know which temper but they’re good at getting the hardness (strength) you want. BTW, Finkl is a hot work tools steel house mostly with their own VAR furnaces. Really good stuff...

Good luck,
Matt
 
Matt_Maguire said:
Making tough gears? LaSalle ETD150 is a 4142 doped with selenium. Elevated temp drawn, quenched & tempered. It WILL test 32Rc (30-34 limits, or call Wilson to get your tester fixed…). Machinability rating 75% of 1212 so plenty good with coated HSS. Find a dist thru Niagra – LaSalle. Or just google "ETD150 steel" and a link should show up.

2nd choice, Productigear in Chicago buys FX-Xtra from Finkl (same city) for tough ready to machine gear stock. I don’t know which temper but they’re good at getting the hardness (strength) you want. BTW, Finkl is a hot work tools steel house mostly with their own VAR furnaces. Really good stuff...

Good luck,
Matt
Click to expand...

I am familiar with ETD 150. Last I knew, was only made up to 3-9/16 dia. http://www.niagaralasalle.com/pdf/etd150casestudies.pdf
 
Gerdau Steel makes some fine 4140/42PHT, see if a distributor can source from them.

Eaton Steel in Detroit claims to be the "Costco" of steel distributors, and can find or heat treat about anything. If you buy enough tonnage, it could be worth the freight cost.

Good luck,

ToolCat
 
10 fingers said:
I am familiar with ETD 150. Last I knew, was only made up to 3-9/16 dia. http://www.niagaralasalle.com/pdf/etd150casestudies.pdf
Click to expand...


Yeah, I am sure that it is only available into the 3 inches area as it is "drawn".
Not much actually drawn over 3.5" AFAIK.

ETD is VERY expensive too.
I have a bunch on order right now, and the best price that I found was just under $3.
(waiting for mill run)

Those that had stock were asking up to $5, and that is the 5000# price too!



And Amanda @ Eaton told me the other day that she never even heard of that material, so ....



----------------------

Think Snow Eh!
Ox
 
Milland said:
Due to Covid, that mill had to retool to churn out baguettes. I did hear they had complaints about the first batches, when they hadn't gotten all the remaining steel out of the mix.

[Yes, "churning out baguettes" is a terrible mixed-metaphor]
Click to expand...

Mixed-metaphors are the yeast of your problems. We really knead to stay on-topic.
 
Gear cutting and carbide vs HSS tooling.
Oh-my over the last 50 decades. Newer carbides better, newer gear machines are faster.
Older machines and making carbide work economically is not so easy. Dad chased this white whale for quite a while to no success.
We do have a top notch gear cutting member here whom I think has made it work for him. Other side not talking to me so often so maybe not so good results.
Bob
 
CarbideBob said:
We do have a gear cutting member who I think has made it work for him.
Click to expand...
Zahnrad replicated what Pfauter did in the seventies. The problem was not so much "would it work" as "how much $$$ ?" Works for zahn because he does it for himself.

Have had carbide and carbide-tipped hobs for ages too. Again, the problem is cost, not whether it works. Our gashers used all carbide but the cutters cost $8,000 apiece. Have to make quite a few parts to justify that.
 
Matt_Maguire said:
2nd choice, Productigear in Chicago buys FX-Xtra from Finkl (same city) for tough ready to machine gear stock. I don’t know which temper but they’re good at getting the hardness (strength) you want. BTW, Finkl is a hot work tools steel house mostly with their own VAR furnaces. Really good stuff...

Good luck,
Matt
Click to expand...

I'm with you. The 4140 Q&T we bought was always in the middle of spec. Which was 28-32Rc. Generally it tested at 30-32. Never had a problem with finish or tool life, but weren't using HSS for anything but drilling.

Funny you mention those two, I've done business with both. Productigear makes some good gears, we've had quite a few made there over the years. They aren't cheap though.

I worked in a shop that made a forging press cylinder for Finkl also. It was a big boy - for a 5,000 ton press. I did some of the lathe work and also the line boring on the HBM (with two other guys, we were 3 shifts there).

There was a mishap during the lathe work, some idiot had balanced a boring bar (maybe 5' - 6' long) on a single 4x4. One of the guys on another shift stepped on one end to get a step up so he could hook a steel cable to the crane not realizing that the boring bar was precariously balanced in the middle. He lost his balance when that end dropped and that caused the back of his hand to be drawn across the end of the job, which he had not properly chamfered and was near razor sharp. He closed his hand and couldn't reopen it. The sharp edge had cut all the tendons to his fingers in the back of his hand. As you can imagine, he had a very complex surgery and his hand was never the same again. We never did find out who had left the boring bar that way.
 
I cut one of those same tendons on the little caps that was on a 55 gal drum.

I decided that I would actually go see someone better qualified at body repairs than myself on that one, as my middle finger dangled.
(looked like a *********)

He stitched me up and told me to not doo anything with it for a few weeks.

I went sledding the next weekend, but I was careful with it, but those are all just "return" muscles/tendons anyhow.
Not like you are ever going to really overwork those.


Your guy must have done a lot more than just shear the tendons in two to have that much trouble.

Only trouble that I have is that my skin seemed to heal fast to the tendon, but it's never an issue anyhow.
The sun still comes up in the east every day, so I guess all is well.



----------------

Think Snow Eh!
Ox
 
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