Do it yourself alignment

i simply cannot comprehend how you think a drawing can possibly, in any way, contradict the metallography of service failures.

no, i just have service failure analysis to go on - sorry about that.

i don't now, but i used to!

apparently you missed it when i referred to "coatings" above. apparently you missed it when i pointed you towards fabrication methodology above.

if you did metallography and understood fabrication technology, sure. but if you don't have the understanding of service failures, you can't differentiate between mistake and policy. a spring failing as a statistical anomaly, or because of physical damage that sets a fatigue initiator, is not a concern. a spring that is guaranteed to break because of deliberate cost cutting, i.e. one that is not heat treated, shot peened or properly coated, then that is. frod springs are not heat treated, peened and just cheaply painted. if you think you can argue against those facts, then you don't understand how you're completely out of your depth.

Reply to
jim beam
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I'll grant that you might be able to tell whether a spring is peened or not by inspection, assuming that it is not too badly rusted, but how are you determining what coating is used and whether or not the spring is heat treated?

Reply to
N8N

There are ways to tell heat treatment. A surface hardness test would be enough for a 'yes' or 'no' probably. If a spring is broken examination of the break will give a good indication as well. However springs aren't heat treated as general practice for the purpose of this discussion. Wire is heat treated and springs are made from that wire. Heat treating springs wouldn't be cost effective. Because they are mostly air and get tangled up if tightly arranged. Also dimensional changes could be an issue.

As to coatings, again there is some rough info that could be gathered. I wouldn't call the coating that was on my '97's springs to be 'cheap paint'. It didn't act like 'cheap paint', look like 'cheap paint' or perform like 'cheap paint'.

Reply to
Brent

you can't tell if it's peened just by inspection - and i didn't say you could. i said metallography - and if you do that, it's very easy.

Reply to
jim beam

you shouldn't have any difference. spring steels are supposed to have very limited ductility - the failure point is nearly the same as the end of the hookes law region on the graph.

springs break from fatigue. you won't see any difference in the "beach mark" region, and in the brittle region, same again. unless there's a heat treatment problem causing excess grain growth.

frod don't heat threat - it saves money.

but it's very effective at stress relief, and that's an essential operation.

you'll need to re-state that - makes no sense as written.

not if properly dimensioned in the first place.

"cheap paint" is thin, porous, and permits rust. [that's easy enough to spot isn't it???!] quality coatings, like a good thick elastic epoxy, is not only rust proof, but helps considerably with stone damage.

Reply to
jim beam

Your claim is that the springs aren't heat treated at all.

So claims the abusive, abrasive, anonymous usenet loudmouth of rec.autos.tech. Yet you don't back up this claim.

Essential for some things, not for others. Another claim you don't back up. Anyway this is again another place where you need to tighten up on your terminology if you wish to be properly understood. Prior it appeared you were blathering about heat treatment to produce desired material properties rather than stress relieving.

Aren't you familiar with heat treating? It is far cheaper to throw parts in bin and heat treat them than it is to pay someone to carefully arrange them in fixtures, carriers, etc. Also volume is important when it comes to cost. Automotive springs carefully arranged take up a lot of space. It's things like this that show exactly what you are.

"properly dimensioned" LOL. You've clearly never had to balance part design and manufacturing processes. Properly dimensioned for what? The design or the heat treatment process?

What I saw was not thin, was not porous, and originally fairly elastic. It eventually failed because it became brittle after a dozen years exposed to chicago's environment. Now you could claim this to be unacceptable and that's your opinion and that's fine. However what it was exposed to likely exceeds any manufacturer's requirements.

Reply to
Brent

Ludicrous claim. I was a heat-treater at IH in Chicago for years, and a heavy press operator, heavy shear operator, and an 8-torch machine operator. Just about every non-drive train part of those dozers went through my hands, shovel, or tongs - many, many times. Except for sheet and plate steel cut and formed to a structural shape, EVERYTHING got heat-treated. And I'm sure even the sheet and plate was spec'ed for composition/heat-treating from the mills. IH was far from a paragon of quality, one reason they went bankrupt. But even that lousy company knew the basics of heat-treating, and the necessity of heat-treating. There's no talking to somebody who has a hard-on against a manufacturer. It's blind raving, and you're wasting your time.

Reply to
Vic Smith

jim beam wrote in news:ks7o4v$smk$ snipped-for-privacy@dont-email.me:

You ought to do a a quick Google before posting silliness, just to make sure others can't find contradictory evidence in seconds.

FORD might not do its own heat-treatment, but then they wouldn't need to: that would be their suppliers' job.

Reply to
Tegger

you need to read your own cite tegger - that is a heat treatment spec guide, but nowhere does it say it's specific to springs - it's a general paper for treatment control. and many /other/ components are heat treated.

Reply to
jim beam

manufacturers that know what they're doing and have some vague semblance of wanting to deliver something for the money they charge, do indeed heat stress relieve springs, shot peen them, then coat them.

frod do not heat treat their springs. as i said, it's because it saves money. and they've spent a lot of money/smarts figuring /how/:

Reply to
jim beam

Did you read your cite? " Ford Motor Company has developed a potentially cost saving cold-coiling process in which less time is spent treating spring metal at elevated temperatures."

In fact that article confirms everything I've stated in this thread branch and shows the argument I was holding back to hit you over the head with, which is that there is usually more than one way to skin a cat.

Your cite disproves your own claims.

Reply to
Brent

dude, READ it. they're heat treated /before/ forming. that's not really a heat treatment as far as the manufacture is concerned because it does NOT address residual stress, and residual stress kills springs. for a guy that keeps trying to say they know what they're talking about, you're doing a damned good job proving you don't.

you're so busy falling over yourself trying to say nay that you're not even reading it.

Reply to
jim beam

You should quite while you're behind.

Reply to
Alan Baker

Yabut, that paper actually says, "The resulting residual stresses can be essentially eliminated by a relatively low temperature tempering treatment following the cold coiling."

So residual stress is addressed, and low temp tempering is heat treating the coils after coiling, which started with heat treated steel. Just sounds like a specific heat treating/coiling process to me. Do you know what process Honda uses? That paper is pretty old, and I have no idea what process Ford actually uses. But this seems to indicate the that coiling previously heat treated wire is common for automotive springs.

It appears there were a number of coil spring failures around the time of the paper you cited, and some much later. Using "nhtsa recall coil spring failure" as a google argument, you can see them. Ford does seem to have more than their share, but there are others. I'm not about to dig through the data. I couldn't find any accusations that a particular method of heat treating springs was behind the recalls. I'm more inclined to see a jot of bad engineering with a dash of bad manufacturing QC behind it all.. Looks like Tanabe uses a similar process in making its springs.

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You get a hard-on going after Ford, that's all.

Reply to
Vic Smith

jim beam wrote in news:ksa5n2$o06$ snipped-for-privacy@dont-email.me:

Oh, so Ford heat-treats everything BUT springs? Right.

Reply to
Tegger

It's pretty clear you don't have a clue. Ford develops a process that requires less time and energy to stress relieve a spring made of pre-heat treated wire and your mind turns this into 'ford doesn't heat treat springs'.

Reply to
Brent

That's what I told you several posts ago.

residual stress is addressed. Read the entire article. Pay attention to figures 2 and 3.

Stop projecting Mr. Beam. If you read it you can't comprehend it. The proposed process in the article produces a spring with all desired characteristics including reduction of residual stress.

Reply to
Brent

that is the traditional route. reading further about the three samples they test, it says "the second one is cold-coiled /after/ a relatively low temper". my emphasis.

this is the key part because any tempering of bulk rod is way cheaper than that of individual springs. and given the process described for the third sample, probably of little importance.

"ready, fire, aim". you got them in the wrong order. any heating process before forming does not address residual stress created in coiling.

nope, it's very much different because the order is completely unconventional - and gives inferior results. but it is very much cheaper.

"traditional", i.e. coil, heat treat, peen, coat. or at least, they used to. they used to make forged cranks too but have followed frod and now cast.

that paper is just regarding cold coiling, which is noting special. lots of springs are cold coiled. it's whether they're heat treated afterwards that is the key issue. frod choose not to because it saves money.

those are forming failures due to the low ductility of the wire stock. that is one of the problems with cold forming. [your last cite says that too.]

that's because they're not heat stress relieved post-forming. ["post forming" is the most essential point to note.]

qc is essential, but that only addresses consistency, not the fundamental process route.

they cold coil, then heat treat, then shot peen. just like i said for traditional springs. the only bit that might be confusing is that they call their heat treatment "cold tempering". by metallurgical standards it is cold - no recrystallization, but the temperature is sufficient to stress relieve.

no, they're just the industry leaders in cheap and shoddy. and they regard the cost of compensation to the families of the people that their cheap and shoddy kills as simply a cost of doing business.

Reply to
jim beam

??? was that the post about "air" and "tangling"?

please tell me you're joking. please? fig 2 is pre "bulldozing". fig

3 is post "bulldozing". that's what the whole paper is about. the hints to this should have been in para 1 where it states that frod "developed a potentially cost saving cold coiling process". it goes on to say, as i have said, that the resulting "residual stress pattern within the as-cold-coiled spring is undesirable ... for its effect on fatigue". paragraph 2 then says exactly what i told you before about the traditional forming route and contrasts it with the frod route.

BY ALL COLD FORMING!!! i.e. no heat treatment other then the cheap bulk rod feed stock, which doesn't even need to be done at the coiling plant. and no shot peening.

it's just amazing - you accuse me of precisely the reading comprehension failure you yourself are demonstrating. but i guess that's on par with the guy that asks for drawings of a post-failure event.

Reply to
jim beam

they don't heat treat everything. your cite was simply a guide for control process, /where heat treatment is employed/.

Reply to
jim beam

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