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Properties of 52100 annealed condition?

M. Moore

Titanium
Joined
Jun 8, 2007
Location
Vancouver Island, B.C. Canada
I need to make some small thrust washers for a diff repair, I can heat treat if required.
The question came up in regards to the strength and performance of 52100 in the annealed state.
I have searched and searched but only found info on how the steel performs after heat treat.
It is such a good quality steel and turns beautifully it would be handy to know how it would perform without heat treat.

Hoping to learn something new.....

Thanks in advance!


Michael
 
It's a high carbon, low alloy steel with manganese, I suspect (but haven't cut it soft myself), that it's fairly tough, perhaps "smeary" when annealed. Probably not great tensile properties when soft if that matters to you.

AISI 52100 Alloy Steel (UNS G52986)

If these will see actual thrust bearing loads, not just acting as spacers, I'd want a hard surface, and maybe a tougher steel to prevent shattering if a thin section is shocked. Hardened 52100 is not a tough material.
 
It's a high carbon, low alloy steel with manganese, I suspect (but haven't cut it soft myself), that it's fairly tough, perhaps "smeary" when annealed.
Not smeary at all, turns beautifully, a lot like a bunch of other semi-exotic alloys (vascomax, 9310, etc).

You do have to watch the chips on these, as a light finish cut will create a long stringy whisker-like chip that doesn't like to break, so if it gets wrapped around the tool, bye-bye finish.
 
Not smeary at all, turns beautifully, a lot like a bunch of other semi-exotic alloys (vascomax, 9310, etc).

You do have to watch the chips on these, as a light finish cut will create a long stringy whisker-like chip that doesn't like to break, so if it gets wrapped around the tool, bye-bye finish.

Annealed? 40% machinability of 1212 according to my link, when optimized by spherodizing annealing.

I've cut bearing races in the hard state, and agree that before the carbide breaks down it does cut nicely.
 
Yes, it turns beautifully, not smeary at all. Even with my limited skills it is very nice to turn.
The parts are a bit thin, OD of 2.375 and ID of 1.625, .085 thick.
These are spacers/thrust washers in the diff of a medium sized backhoe/loader. (Case 580D)

The original spacer grenaded and is in the bottom of the gearbox, the other spacer is fine. Material spark tests exactly the same as 52100.
The originals are pretty easy to file so hardened and drawn back to a fairly soft state I presume. They only lasted between 20 and 30 years, hard to pin down the exact date of destruction.
These are in between the side gears and the pinion gears, one on each side of the ring gear. The thickness of each spacer creates the lash for the pinion gears. The originals were a bit thicker at about 0.110 and with all the wear the replacements needed to be a bit thinner to get the lash back in spec.

The broken bits have an interesting crystalline structure and almost look like cast iron but are definitely not cast iron. Spark test is clear on material type.
 
99% positive that no one has been in there since new. OEM makes replacement washers in 6 different thickness'.
Very low turning rpm. Possibly high thrust given the weight of the machine and these side gears drive the large bull gears for the rear axles.
Mostly these washers turn with the side gears except when turning the machine, then the diff kicks in and these washers will rotate with their side gear.
Diff assembly is set with bearing preload at rolling 5-8 foot pounds.
 
Annealed? 40% machinability of 1212 according to my link, ...
Those machinability specs rely heavily on speed, though. A lot of materials have high machinability ratings because you can spin the shit out of them but the finish sucks, where plenty of low machinability materials have to be cut slow but come out with a nice finish.

"Machinability" outta the book is not the complete answer.
 
Case did things to a high standard. These rear ends are known to be very tough and long lasting.
This machine was abused badly and it still ran, quite a bit of noise but it was still moving.
So, to use 52100 and heat treat, guessing on the hardness or use 4340 htsr as suggested by a machinist friend. I am just a wannabe machinist with some very good tools.
 
and heat treat, guessing on the hardness or use 4340 htsr as suggested by a machinist friend.
Depends on what you want, really ... 52100 is going to be vacuum melt and high purity, stable in heat treat, and you'll have no problem getting well over 58 Rc. Timken has found that 58 is a decisive number for rolling element bearings; below that and life is considerably shorter. 4140 and 4340 are going to give you exactly the same results - the only reason to use 4340 is if the section is thicker than an inch, 4340 quenches deeper. Other than that the results are pretty much equal. You'e not going to get much over 45 Rc with any of the 4000-series steels.

From your description of the use, I'd probably go with the 52100, mill a spiral slot in the blank for oiling, then have a reputable heat treater bring them up to about 61-63. Then grind flat.

But that's just me :)

(You want a good heat treater. I once had a disaster with a batch of thrust bearings because the well-known reputable place I used messed up bad. By the time I made new ones and replaced all the failures I lost my ass. All the heat treater is responsible for is the cost of the heat treat. Wow, $75 on a $3,500 job. I don't have happy memories of 52100 for this reason, but it's not the steel's fault.)
 
(You want a good heat treater. I once had a disaster with a batch of thrust bearings because the well-known reputable place I used messed up bad. By the time I made new ones and replaced all the failures I lost my ass. All the heat treater is responsible for is the cost of the heat treat. Wow, $75 on a $3,500 job. I don't have happy memories of 52100 for this reason, but it's not the steel's fault.)

Somebody needs to sell HT and plating insurance. But either the fees would be too high, or they'd go bankrupt quickly...
 
I think your 52100 will do just fine annealed. I have some bar ends from a company that made large studs in the annealed condition. Yes, it turns very nicely. Your description of the break sounds like steel with a large grain size, so I assume they were used in the annealed condition. If you were to heat treat a replacement, you would want to be sure the final hardness is at least 4 points below that of the mating gear.
 
If your carrier is worn would you not need thicker washers? I have built tractor pulling rear ends many in the 5 to 10000 hp range we grind the gears flat on the back , machine a receiver groove in to the diff housing for a hard thrust washer and needle thrust. The needles run right on the backside of the side gears. No failures. And the differential is turning just as fast as you cars the reduction happens in the final drive.


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so you have some "annealed" 51200 that machines well? the best source as to mechanical properties would be the supplier. anealed is not a precise state, not like you flip a switch and it comes out annealed. usually they state/are able to tell you what hardness it was annealed to. but thats not very dependable (often a max. value is given) because its not important. some stock comes annealed and cold worked. i would expect 650-800 Mpa tensile. mcmaster states 24 hrc. expect around 20% elongation.

i didnt catch if its a spacer or thrust bearing. probably no good for the bearing.
 
Johnoder,
I would be keen to see the spark test results on that material.

So we have one vote for and one vote against at this point.

Turbo, the wear is happening on the gears not the thrust washer or its bearing surfaces. This means a thinner spacer is needed to reduce the backlash.

I don’t think the damaged spacer wore down and then disintegrated it probably had a super shock event or someone spun the wheel for a long time with low oil but just guessing on that.....

Aland islands is an odd place for such large tractor pull events?

Turbo, are you familiar with the Case style diff? This is the first diff I have ever opened and apparently Case made their own design which is quite different from most others.

Here is a photo of the side gear, the thrust washer is on the large end that mates with the pinion gears.
 

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The super shock event may have been when the brake on that side was totally destroyed. Surprisingly no damage to the spline on the side gear. The parts fell out like rain when I cracked open the brake housing.

The cast iron brake parts were no match for the steel in the side gear.....must have made quite a crunching sound.

So one question for those who may know, how tough is annealed 52100, will it break apart with a sharp blow or will it bend and stretch? I have an offcut washer but have’t tested it yet.
 
Well, annealed will be much tougher than when hardened to ~63RC.

From: Encore Metals - E52100

Typical Mechanical Properties (Annealed)

Yield - 85,000 psi
Tensile - 105,000 psi
Elongation - 17%
Reduction Area - 50%
BHN at surface - 228

So not super ductile, but will bend before breaking unless flexed paper-clip style.
 








 
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