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Main
Date: 24 Sep 2007 14:35:49
From: still me
Subject: Forged vs. ?
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I've seen some quill stems the are marked as "forged". For example, I
have some old SR stems that are forged, others that are not.
What is the difference in the manufacturing process between "forged"
and "whatever"? Is "whatever" usually cast ? I understand steel
forging vs stamping, but what is the difference in process with alloy
parts like stems? Do they repeatedly stamp hot alloy into shape when
forging alloy or is it really just a one step stamping ?
More importantly, what is the general difference in the metal
characteristics when they are done?
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Date: 26 Sep 2007 20:41:23
From:
Subject: Re: Forged vs. ?
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On Sep 26, 9:22 pm, Jasper Janssen <jas...@jjanssen.org > wrote:
> On Mon, 24 Sep 2007 22:15:56 -0500, A Muzi <a...@yellowjersey.org> wrote:
> >>
> >Jasper Janssen wrote:
> >> 'Cold-forged' steel AFAIK just starts at room temp, after being
> >> spectacularly deformed under massive pressure, it heats up to "can burn
> >> you" levels at least, when it comes out of the process.
>
> >> Drop-forged, as seem on many wrenches (especially cheap ones), AFAIK
> >> involves using a Very Big Hammer (several tons of weight) which fall from
> >> a height onto the steel and shape it that way, in one go. I think those
> >> typically hot-forge.
>
> >Have you seen a 5 or ten ton forge? It drops. That's what it is/does.
>
> But on warm or cold steel?
AFAIK, fairly large steel parts like wrenches that are made in large
forging presses are always done hot. I'm talking about impression die
forging, where the die that does the shaping has cavities in the shape
of the part. Steel gets much, much more ductile when it's raised
above a certain temperature (roughly 1400 deg. F). That allows it to
flow into complex shapes.
Steel in the form of thin rods or sheets is formed at room
temperature. But doing a wrench handle that way would destroy forging
dies in short order, even though they're made of very strong tool
steels.
- Frank Krygowski
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Date: 25 Sep 2007 20:03:53
From: jbollyn@gmail.com
Subject: Re: Forged vs. ?
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On Sep 25, 2:24 pm, still me <wheeled...@yahoo.com > wrote:
> On Tue, 25 Sep 2007 11:38:51 -0700, "* * Chas"
>
> <verktygj...@aol.spamski.com> wrote:
>
> Follow up question... in the days of yore, a blacksmith would
> repeatedly pound the part (iron or steel) into shape. It seems to me
> (intuitively) that this would tend to arrange the steel in a much more
> ordered fashion than simply hitting it with a massive multi-ton press
> just once. Or maybe in the multi-ton, he parts that actually get
> formed into a bend would pick up strength, but the parts that are left
> unbent would not gain strength.
>
> Comments?
My understanding is, the entire forging gains strength, because 'the
metal's grain flow changes into the shape of the part'. If you go to
this link
http://en.wikipedia.org/wiki/Forge and click on the image in the
'Forging' section three times, you will get a close-up view of the
grain flow.
Jay
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Date: 27 Sep 2007 20:04:59
From: jim beam
Subject: Re: Forged vs. ?
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jbollyn@gmail.com wrote:
> On Sep 25, 2:24 pm, still me <wheeled...@yahoo.com> wrote:
>> On Tue, 25 Sep 2007 11:38:51 -0700, "* * Chas"
>>
>> <verktygj...@aol.spamski.com> wrote:
>>
>> Follow up question... in the days of yore, a blacksmith would
>> repeatedly pound the part (iron or steel) into shape. It seems to me
>> (intuitively) that this would tend to arrange the steel in a much more
>> ordered fashion than simply hitting it with a massive multi-ton press
>> just once. Or maybe in the multi-ton, he parts that actually get
>> formed into a bend would pick up strength, but the parts that are left
>> unbent would not gain strength.
>>
>> Comments?
>
>
> My understanding is, the entire forging gains strength, because 'the
> metal's grain flow changes into the shape of the part'. If you go to
> this link
>
> http://en.wikipedia.org/wiki/Forge and click on the image in the
> 'Forging' section three times, you will get a close-up view of the
> grain flow.
>
> Jay
>
>
>
great example.
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Date: 25 Sep 2007 14:32:09
From:
Subject: Re: Forged vs. ?
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On Sep 25, 9:06 am, jim beam <spamvor...@bad.example.net > wrote:
> * * Chas wrote:
>
> > My objection is to the term "melt forged". Call it a high precision
> > casting or something similar.
>
> the material is a slurry of solid particles with just a little
> interstitial liquid at the time of forming. like ice slush in a
> slurpee. it's definitely not "casting" in any traditional sense.
By the same token, it's definitely not "forging" in any traditional
sense.
- Frank Krygowski
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Date: 27 Sep 2007 20:03:03
From: jim beam
Subject: Re: Forged vs. ?
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frkrygow@gmail.com wrote:
> On Sep 25, 9:06 am, jim beam <spamvor...@bad.example.net> wrote:
>> * * Chas wrote:
>>
>>> My objection is to the term "melt forged". Call it a high precision
>>> casting or something similar.
>> the material is a slurry of solid particles with just a little
>> interstitial liquid at the time of forming. like ice slush in a
>> slurpee. it's definitely not "casting" in any traditional sense.
>
> By the same token, it's definitely not "forging" in any traditional
> sense.
>
> - Frank Krygowski
>
>
true.
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Date: 25 Sep 2007 03:37:30
From:
Subject: Re: Forged vs. ?
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On Sep 24, 3:46 pm, "* * Chas" <verktygj...@aol.spamski.com > wrote:
>
> "Melt forged" was/is a BS term for injection molding, a method for making
> high quality castings.
I think you meant die casting, not injection molding. Although the
processes are conceptually very similar, when it's done with metal,
it's called die casting. When it's done with plastic, it's called
injection molding. At least, that's true everywhere I've come across
it.
> A casting is still a casting and doesn't have the benefits of increased
> metal density that comes from forging.
Hmm. Well, forgings definitely tend to be stronger per unit weight,
but there are a wide variety of casting processes. Some are clearly
better than others regarding accuracy, finish, mechanical properties,
etc.
As Andrew noted, it's certainly possible to make perfectly acceptable
parts by casting. The cast parts may be a bit heavier, but the
difference is probably undetectable to most riders.
When you get to the point where you're counting grams, then yes, you
probably want forged parts.
Unless you go with carbon fiber. ;-)
- Frank Krygowski
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Date: 26 Sep 2007 11:13:32
From: * * Chas
Subject: Re: Forged vs. ?
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<frkrygow@gmail.com > wrote in message
news:1190691450.182659.323440@22g2000hsm.googlegroups.com...
> On Sep 24, 3:46 pm, "* * Chas" <verktygj...@aol.spamski.com> wrote:
> >
> > "Melt forged" was/is a BS term for injection molding, a method for
making
> > high quality castings.
>
> I think you meant die casting, not injection molding. Although the
> processes are conceptually very similar, when it's done with metal,
> it's called die casting. When it's done with plastic, it's called
> injection molding. At least, that's true everywhere I've come across
> it.
>
I was thinking "die casting" when I wrote "injection molding" in several
messages.
The term injection molding usually refers to the plastics industry but it
can be used to describe the manufacturing processes for both plastic
molding and metal die casting.
http://www.pcc-aft.com/aboutus.htm
I was unfamiliar with the term thixoforming. I ran across the above site
searching on thixoforming. I heard about the process about 10 years ago
when I visited an aluminum mfg. who was making the slugs for the process
but it was called a number of different names. I've never seen the actual
process in use.
No matter how good the results, thixoforming, vacuum casting melt forging
or what ever it's called is still not forging.
Chas.
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Date: 26 Sep 2007 18:41:50
From: A Muzi
Subject: Re: Forged vs. ?
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>> "* * Chas" <verktygj...@aol.spamski.com> wrote:
>>> "Melt forged" was/is a BS term for injection molding, a method for
>>> making high quality castings.
> <frkrygow@gmail.com> wrote
>> I think you meant die casting, not injection molding. Although the
>> processes are conceptually very similar, when it's done with metal,
>> it's called die casting. When it's done with plastic, it's called
>> injection molding. At least, that's true everywhere I've come across
>> it.
* * Chas wrote:
> I was thinking "die casting" when I wrote "injection molding" in several
> messages.
>
> The term injection molding usually refers to the plastics industry but it
> can be used to describe the manufacturing processes for both plastic
> molding and metal die casting.
>
> http://www.pcc-aft.com/aboutus.htm
>
> I was unfamiliar with the term thixoforming. I ran across the above site
> searching on thixoforming. I heard about the process about 10 years ago
> when I visited an aluminum mfg. who was making the slugs for the process
> but it was called a number of different names. I've never seen the actual
> process in use.
>
> No matter how good the results, thixoforming, vacuum casting melt forging
> or what ever it's called is still not forging.
Right.
But the greater bulk of our industry's mid to low end equipment is much
the better for these processes, gravity castings being pretty much
obsolete for aluminum bicycle parts. No one makes an AVA or Pivo cast
stem or its equivalent now fortunately! A choice of Record or sand cast
is not a reasonable choice for everyone.
(jim beam first introduced me to the the term 'thixoform' here. The
SR-Sakae folks all said 'melt-forge')
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 27 Sep 2007 20:04:21
From: jim beam
Subject: Re: Forged vs. ?
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A Muzi wrote:
>>> "* * Chas" <verktygj...@aol.spamski.com> wrote:
>>>> "Melt forged" was/is a BS term for injection molding, a method for
>>>> making high quality castings.
>
>> <frkrygow@gmail.com> wrote
>>> I think you meant die casting, not injection molding. Although the
>>> processes are conceptually very similar, when it's done with metal,
>>> it's called die casting. When it's done with plastic, it's called
>>> injection molding. At least, that's true everywhere I've come across
>>> it.
>
> * * Chas wrote:
>> I was thinking "die casting" when I wrote "injection molding" in several
>> messages.
>>
>> The term injection molding usually refers to the plastics industry but it
>> can be used to describe the manufacturing processes for both plastic
>> molding and metal die casting.
>>
>> http://www.pcc-aft.com/aboutus.htm
>>
>> I was unfamiliar with the term thixoforming. I ran across the above site
>> searching on thixoforming. I heard about the process about 10 years ago
>> when I visited an aluminum mfg. who was making the slugs for the process
>> but it was called a number of different names. I've never seen the actual
>> process in use.
>>
>> No matter how good the results, thixoforming, vacuum casting melt forging
>> or what ever it's called is still not forging.
>
> Right.
> But the greater bulk of our industry's mid to low end equipment is much
> the better for these processes, gravity castings being pretty much
> obsolete for aluminum bicycle parts. No one makes an AVA or Pivo cast
> stem or its equivalent now fortunately! A choice of Record or sand cast
> is not a reasonable choice for everyone.
> (jim beam first introduced me to the the term 'thixoform' here. The
> SR-Sakae folks all said 'melt-forge')
that's because "melt-forge" sounds better than "slurry-sloshing"!
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Date: 24 Sep 2007 22:25:09
From: * * Chas
Subject: Re: Forged vs. ?
|
<frkrygow@gmail.com > wrote in message
news:1190691450.182659.323440@22g2000hsm.googlegroups.com...
> On Sep 24, 3:46 pm, "* * Chas" <verktygj...@aol.spamski.com> wrote:
> >
> > "Melt forged" was/is a BS term for injection molding, a method for
making
> > high quality castings.
>
> I think you meant die casting, not injection molding. Although the
> processes are conceptually very similar, when it's done with metal,
> it's called die casting. When it's done with plastic, it's called
> injection molding. At least, that's true everywhere I've come across
> it.
>
> > A casting is still a casting and doesn't have the benefits of
increased
> > metal density that comes from forging.
>
> Hmm. Well, forgings definitely tend to be stronger per unit weight,
> but there are a wide variety of casting processes. Some are clearly
> better than others regarding accuracy, finish, mechanical properties,
> etc.
>
> As Andrew noted, it's certainly possible to make perfectly acceptable
> parts by casting. The cast parts may be a bit heavier, but the
> difference is probably undetectable to most riders.
>
> When you get to the point where you're counting grams, then yes, you
> probably want forged parts.
>
> Unless you go with carbon fiber. ;-)
>
> - Frank Krygowski
>
You're right, the process is called Die Casting. I was in a hurry when I
wrote that. I guess that I'm getting old and the memory gland doesn't
always work as well as it once did. ;-)
Die casting is used to make castings from aluminum, magnesium, zinc alloys
(zamac), and copper and it's alloys (brass & bronze).
I object to the term "melt forged" which is a misleading misnomer rather
than castings in general.
Someone at a LBS showed me a hollow Shimano crank arm that had been cut in
half. He said Shimano told him it was a forging. I looked it over and
could tell it had been cast.
Chas.
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Date: 25 Sep 2007 06:09:58
From: jim beam
Subject: Re: Forged vs. ?
|
* * Chas wrote:
> <frkrygow@gmail.com> wrote in message
> news:1190691450.182659.323440@22g2000hsm.googlegroups.com...
>> On Sep 24, 3:46 pm, "* * Chas" <verktygj...@aol.spamski.com> wrote:
>>> "Melt forged" was/is a BS term for injection molding, a method for
> making
>>> high quality castings.
>> I think you meant die casting, not injection molding. Although the
>> processes are conceptually very similar, when it's done with metal,
>> it's called die casting. When it's done with plastic, it's called
>> injection molding. At least, that's true everywhere I've come across
>> it.
>>
>>> A casting is still a casting and doesn't have the benefits of
> increased
>>> metal density that comes from forging.
>> Hmm. Well, forgings definitely tend to be stronger per unit weight,
>> but there are a wide variety of casting processes. Some are clearly
>> better than others regarding accuracy, finish, mechanical properties,
>> etc.
>>
>> As Andrew noted, it's certainly possible to make perfectly acceptable
>> parts by casting. The cast parts may be a bit heavier, but the
>> difference is probably undetectable to most riders.
>>
>> When you get to the point where you're counting grams, then yes, you
>> probably want forged parts.
>>
>> Unless you go with carbon fiber. ;-)
>>
>> - Frank Krygowski
>>
>
> You're right, the process is called Die Casting. I was in a hurry when I
> wrote that. I guess that I'm getting old and the memory gland doesn't
> always work as well as it once did. ;-)
>
> Die casting is used to make castings from aluminum, magnesium, zinc alloys
> (zamac), and copper and it's alloys (brass & bronze).
>
> I object to the term "melt forged" which is a misleading misnomer rather
> than castings in general.
it's not. "casting" is used for liquid solidification. "melt forged"
or thixoforming does in no way produce the same product as casting.
>
> Someone at a LBS showed me a hollow Shimano crank arm that had been cut in
> half. He said Shimano told him it was a forging. I looked it over and
> could tell it had been cast.
what features led you that conclusion? i ask because those things are
most definitely forged - and the above illustrates that you have some
confusion on this subject. if you have access to metallography, it
would be good for you to use it - you'll see what i mean the moment you
look down the microscope.
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Date: 24 Sep 2007 13:05:01
From: A Muzi
Subject: Re: Forged vs. ?
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still me wrote:
> I've seen some quill stems the are marked as "forged". For example, I
> have some old SR stems that are forged, others that are not.
>
> What is the difference in the manufacturing process between "forged"
> and "whatever"? Is "whatever" usually cast ? I understand steel
> forging vs stamping, but what is the difference in process with alloy
> parts like stems? Do they repeatedly stamp hot alloy into shape when
> forging alloy or is it really just a one step stamping ?
>
> More importantly, what is the general difference in the metal
> characteristics when they are done?
Same as steel basically.
A forged piece has optimized grain structure and minimal to zero voids
so it can be designed to be a lighter piece at the same strength or with
higher strength at the same weight, compared to a casting.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 24 Sep 2007 17:46:37
From: jbollyn@gmail.com
Subject: Re: Forged vs. ?
|
On Sep 24, 12:30 pm, Art Harris <n...@hotmail.com > wrote:
> "Mike Jacoubowsky" wrote:
> > I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
> > we had "forged" and "melt-forged" stems, the "melt-forged" versions being
> > less-expensive
>
> Yes, "melt forged" and "cold forged."
>
> Art Harris
This link discusses the different forge processes:
http://www.thetandemlink.com/articles/aluminum.html
J.
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Date: 24 Sep 2007 21:53:44
From: jim beam
Subject: Re: Forged vs. ?
|
jbollyn@gmail.com wrote:
> On Sep 24, 12:30 pm, Art Harris <n...@hotmail.com> wrote:
>> "Mike Jacoubowsky" wrote:
>>> I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
>>> we had "forged" and "melt-forged" stems, the "melt-forged" versions being
>>> less-expensive
>> Yes, "melt forged" and "cold forged."
>>
>> Art Harris
>
> This link discusses the different forge processes:
>
> http://www.thetandemlink.com/articles/aluminum.html
>
> J.
>
that is indeed a very good summary.
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Date: 24 Sep 2007 19:42:45
From: still me
Subject: Re: Forged vs. ?
|
On Mon, 24 Sep 2007 17:46:37 -0000, "jbollyn@gmail.com"
<jbollyn@gmail.com > wrote:
>
>This link discusses the different forge processes:
>
>http://www.thetandemlink.com/articles/aluminum.html
Thanks, that link covered it well.
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Date: 27 Sep 2007 10:52:40
From: Donald Gillies
Subject: Re: Forged vs. ?
|
>This link discusses the different forge processes:
>
>http://www.thetandemlink.com/articles/aluminum.html
I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
$29.95 cranks and BB complete) were melt-forged and anodized. So,
there is at least one mistake in this article listed above.
- Don Gillies
San Diego, CA
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Date: 27 Sep 2007 20:02:38
From: jim beam
Subject: Re: Forged vs. ?
|
Donald Gillies wrote:
>> This link discusses the different forge processes:
>>
>> http://www.thetandemlink.com/articles/aluminum.html
>
> I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
> $29.95 cranks and BB complete) were melt-forged
why? what features lead you to that conclusion?
> and anodized. So,
> there is at least one mistake in this article listed above.
>
> - Don Gillies
> San Diego, CA
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Date: 27 Sep 2007 22:26:10
From: A Muzi
Subject: Re: Forged vs. ?
|
> Donald Gillies wrote:
>>> This link discusses the different forge processes:
>>> http://www.thetandemlink.com/articles/aluminum.html
>> I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
>> $29.95 cranks and BB complete) were melt-forged
jim beam wrote:
> why? what features lead you to that conclusion?
Uhh, because the Sugino catalog of the era said, "New! Melt Forged Maxy
Crank"
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 27 Sep 2007 20:58:32
From: jim beam
Subject: Re: Forged vs. ?
|
A Muzi wrote:
>> Donald Gillies wrote:
>>>> This link discusses the different forge processes:
>>>> http://www.thetandemlink.com/articles/aluminum.html
>>> I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
>>> $29.95 cranks and BB complete) were melt-forged
>
> jim beam wrote:
>> why? what features lead you to that conclusion?
>
> Uhh, because the Sugino catalog of the era said, "New! Melt Forged Maxy
> Crank"
that's a long way from "i am pretty certain". and i asked "what
features" because i wanted to know whether he thought he could
distinguish just from external appearance. that ok with you?
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Date: 27 Sep 2007 21:17:26
From: John Thompson
Subject: Re: Forged vs. ?
|
On 2007-09-27, Donald Gillies <gillies@cs.ubc.ca > wrote:
>>This link discusses the different forge processes:
>>
>>http://www.thetandemlink.com/articles/aluminum.html
> I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
> $29.95 cranks and BB complete) were melt-forged and anodized. So,
> there is at least one mistake in this article listed above.
I still have a Maxy of that era, but it is definitely not anodized.
--
John (john@os2.dhs.org)
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Date: 27 Sep 2007 22:15:29
From: A Muzi
Subject: Re: Forged vs. ?
|
>>> This link discusses the different forge processes:
>>> http://www.thetandemlink.com/articles/aluminum.html
> Donald Gillies <gillies@cs.ubc.ca> wrote:
>> I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
>> $29.95 cranks and BB complete) were melt-forged and anodized. So,
>> there is at least one mistake in this article listed above.
John Thompson wrote:
> I still have a Maxy of that era, but it is definitely not anodized.
Original stamped outer ring 3-bolt type were tumble polished I believe.
Later Maxy NJX (the first 110mm chainrings! woo hoo!) and Super Maxy
were anodized. Super Maxy in colors.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
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Date: 28 Sep 2007 20:43:56
From: John Thompson
Subject: Re: Forged vs. ?
|
On 2007-09-28, A Muzi <am@yellowjersey.org > wrote:
>> Donald Gillies <gillies@cs.ubc.ca> wrote:
>>> I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
>>> $29.95 cranks and BB complete) were melt-forged and anodized. So,
>>> there is at least one mistake in this article listed above.
> John Thompson wrote:
>> I still have a Maxy of that era, but it is definitely not anodized.
> Original stamped outer ring 3-bolt type were tumble polished I believe.
>
> Later Maxy NJX (the first 110mm chainrings! woo hoo!) and Super Maxy
> were anodized. Super Maxy in colors.
The Maxy I currently have (5-arm, 144mm BCD spider swaged onto aluminum
arm) has the same unanodized, tumble-polished finish as the original
3-arm swaged Maxy.
--
John (john@os2.dhs.org)
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Date: 28 Sep 2007 01:19:58
From: * * Chas
Subject: Re: Forged vs. ?
|
"A Muzi" <am@yellowjersey.org > wrote in message
news:13foscn9gafdj06@corp.supernews.com...
> >>> This link discusses the different forge processes:
> >>> http://www.thetandemlink.com/articles/aluminum.html
>
> > Donald Gillies <gillies@cs.ubc.ca> wrote:
> >> I am pretty certain that my Sugino Maxy cranks (purchased in 1975-6,
> >> $29.95 cranks and BB complete) were melt-forged and anodized. So,
> >> there is at least one mistake in this article listed above.
>
> John Thompson wrote:
> > I still have a Maxy of that era, but it is definitely not anodized.
>
> Original stamped outer ring 3-bolt type were tumble polished I believe.
>
> Later Maxy NJX (the first 110mm chainrings! woo hoo!) and Super Maxy
> were anodized. Super Maxy in colors.
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
I saw a number of the early aluminum cranks with swaged on chain rings
fail at the swaged joint when these designs first came out. A few Sugino
Maxi cranks plus SR and other makes prejudiced my opinions about these
designs.
Chas.
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Date: 24 Sep 2007 10:30:00
From: Art Harris
Subject: Re: Forged vs. ?
|
"Mike Jacoubowsky" wrote:
> I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
> we had "forged" and "melt-forged" stems, the "melt-forged" versions being
> less-expensive
Yes, "melt forged" and "cold forged."
Art Harris
|
| |
Date: 24 Sep 2007 15:51:51
From: jbollyn@gmail.com
Subject: Re: Forged vs. ?
|
On Sep 24, 9:35 am, still me <wheeled...@yahoo.com > wrote:
> I've seen some quill stems the are marked as "forged". For example, I
> have some old SR stems that are forged, others that are not.
>
> What is the difference in the manufacturing process between "forged"
> and "whatever"? Is "whatever" usually cast ? I understand steel
> forging vs stamping, but what is the difference in process with alloy
> parts like stems? Do they repeatedly stamp hot alloy into shape when
> forging alloy or is it really just a one step stamping ?
>
> More importantly, what is the general difference in the metal
> characteristics when they are done?
How Forgings compare to Castings (quote from http://www.forging.org/facts/faq3.htm
):
Forgings are stronger: Casting cannot obtain the strengthening effects
of hot and cold working. Forging surpasses casting in predictable
strength properties - producing superior strength that is assured,
part to part.
Forging refines defects from cast ingots or continuous cast bar: A
casting has neither grain flow nor directional strength and the
process cannot prevent formation of certain metallurgical defects.
Preworking forge stock produces a grain flow oriented in directions
requiring maximum strength. Dendritic structures, alloy segregation's
and like imperfections are refined in forging.
Forgings are more reliable, less costly: Casting defects occur in a
variety of forms. Because hot working refines grain pattern and
imparts high strength, ductility and resistance properties, forged
products are more reliable. And they are manufactured without the
added costs for tighter process controls and inspection that are
required for casting.
Forgings offer better response to heat treatment: Castings require
close control of melting and cooling processes because alloy
segregation may occur. This results in non-uniform heat treatment
response that can affect straightness of finished parts. Forgings
respond more predictably to heat treatment and offer better
dimensional stability.
Forgings' flexible, cost-effective production adapts to demand: Some
castings, such as special performance castings, require expensive
materials and process controls, and longer lead times. Open-die and
ring rolling are examples of forging processes that adapt to various
production run lengths and enable shortened lead times.
end quote - J.
|
| | |
Date: 24 Sep 2007 11:58:35
From: vey
Subject: Re: Forged vs. ?
|
jbollyn@gmail.com wrote:
>
> How Forgings compare to Castings (quote from http://www.forging.org/facts/faq3.htm
> ):
>
That said, many items are forged, but don't say that they are. I would
think that just about all the stems you will meet would be forged, but I
am sure that there are exceptions if they are particularly old.
|
| | | |
Date: 24 Sep 2007 11:33:17
From: * * Chas
Subject: Re: Forged vs. ?
|
"vey" <junker@ericvey.com > wrote in message
news:fd8ml0$ra1$1@news.datemas.de...
> jbollyn@gmail.com wrote:
>
> >
> > How Forgings compare to Castings (quote from
http://www.forging.org/facts/faq3.htm
> > ):
> >
>
>
> That said, many items are forged, but don't say that they are. I would
> think that just about all the stems you will meet would be forged, but I
> am sure that there are exceptions if they are particularly old.
It can be hard to tell the difference between forged and cast stems.
Most lower cost aluminum alloy stems were/are made from castings.
The Japanese companies SR and Nitto both produced cast aluminum stems.
Only their premium models were forged.
Same thing goes for most European producers. While almost all Italian 3TTT
quill style stems were forged, I think that some of their early cheap
stems were cast. Phillipe stems from France were mostly cast but a few of
their top end stems were forged. Same with French Atax and British GB an
so on.
It was the cheap French stems from the Bike Boom era of the 1970s by Pivo,
AVA, Belleri and others that had a bad reputation for breaking although
I've seen the same problem in SR stems from the same time period.
Several differences between forged and cast bike stems:
In a forging the metal has been compressed and is more dense. It tends to
be more ductile and less likely to develop cracks from normal use or in an
accident.
Cheap poor quality castings can be brittle and crack easily from stress
because of the grain structure of the metal and possible flaws in the
castings.
Castings can be less expensive to produce because they are "near net
sized" and can require less machining and finishing. That's why they've
been used so much for inexpensive bike stems.
Modern casting techniques have resulted in much better quality aluminum
castings. I checked out a lot of threadless stems over the past year. Of
the 100 or so that I looked at most of them appear to have been made from
castings.
Aluminum is either forged at room temperature (cold forged) or heated to
200°F to 800°F (95°C to 430°C)
Many bike stems are touted as being cold forged. Sugino and other Japanese
companies used to claim that their products were "melt forged" - injection
molded castings.
Actual strength and hardness of aluminum depends more on the alloy
composition and subsequent heat treatment than the manufacturing process.
There are a lot of critical aerospace and automotive parts made of cast
aluminum.
I prefer forged aluminum stems myself. Back in the 1970s I had 3 cast
stems break off while riding and it's not a comfortable feeling holding a
set of bars in the air while trying to stop the bike. Two of the events
were while road testing cheap French Bike Boom bikes, the 3rd time was
with a Belleri stem on my own 1973 Gitane Super Corsa. They all failed at
the splits for the wedge cone at the bottom of the quill.
After that I switched to Cinelli and 3TTT forged stems.
Here's some links to sites about aluminum forging:
http://www.aluminum.org/Content/NavigationMenu/The_Industry/-Forgings/Forgings.htm
http://www.metalpass.com/metaldoc/paper.aspx?docID=296
|
| | | | |
Date: 25 Sep 2007 22:21:01
From: _
Subject: Re: Forged vs. ?
|
On Mon, 24 Sep 2007 11:33:17 -0700, * * Chas wrote:
>
> I prefer forged aluminum stems myself. Back in the 1970s I had 3 cast
> stems break off while riding and it's not a comfortable feeling holding a
> set of bars in the air while trying to stop the bike. Two of the events
> were while road testing cheap French Bike Boom bikes, the 3rd time was
> with a Belleri stem on my own 1973 Gitane Super Corsa. They all failed at
> the splits for the wedge cone at the bottom of the quill.
>
I drilled holes at the end of the slots; they were obviously THE place
where cracks would start.
|
| | | | | |
Date: 27 Sep 2007 20:06:21
From: jim beam
Subject: Re: Forged vs. ?
|
_ wrote:
> On Mon, 24 Sep 2007 11:33:17 -0700, * * Chas wrote:
>
>> I prefer forged aluminum stems myself. Back in the 1970s I had 3 cast
>> stems break off while riding and it's not a comfortable feeling holding a
>> set of bars in the air while trying to stop the bike. Two of the events
>> were while road testing cheap French Bike Boom bikes, the 3rd time was
>> with a Belleri stem on my own 1973 Gitane Super Corsa. They all failed at
>> the splits for the wedge cone at the bottom of the quill.
>>
>
> I drilled holes at the end of the slots; they were obviously THE place
> where cracks would start.
why? the slot is not subject to stress perpendicular to its axis -
that's the only situation where the slot will be a stress riser
requiring drilling.
|
| | | | |
Date: 24 Sep 2007 19:47:30
From: Ryan Cousineau
Subject: Re: Forged vs. ?
|
In article <TqWdnekHGunHn2XbnZ2dnUVZ_s2tnZ2d@comcast.com >,
"* * Chas" <verktygjunk@aol.spamski.com > wrote:
> "vey" <junker@ericvey.com> wrote in message
> news:fd8ml0$ra1$1@news.datemas.de...
> > jbollyn@gmail.com wrote:
> Castings can be less expensive to produce because they are "near net
> sized" and can require less machining and finishing. That's why they've
> been used so much for inexpensive bike stems.
Hm. I thought the most fundamental issue, expense-wise, was the cost of
the tooling and the equipment. Forging stamps are expensive, and the
tooling is expensive too, because it has to be very strong, and probably
has a shorter service life than an equivalent casting.
The finishing is surely a factor, though.
> Modern casting techniques have resulted in much better quality aluminum
> castings. I checked out a lot of threadless stems over the past year. Of
> the 100 or so that I looked at most of them appear to have been made from
> castings.
--
Ryan Cousineau rcousine@sfu.ca http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
|
| | | | | |
Date: 25 Sep 2007 11:38:51
From: * * Chas
Subject: Re: Forged vs. ?
|
"Ryan Cousineau" <rcousine@sfu.ca > wrote in message
news:rcousine-0060C2.12472924092007@news.telus.net...
> In article <TqWdnekHGunHn2XbnZ2dnUVZ_s2tnZ2d@comcast.com>,
> "* * Chas" <verktygjunk@aol.spamski.com> wrote:
>
> > "vey" <junker@ericvey.com> wrote in message
> > news:fd8ml0$ra1$1@news.datemas.de...
> > > jbollyn@gmail.com wrote:
>
> > Castings can be less expensive to produce because they are "near net
> > sized" and can require less machining and finishing. That's why
they've
> > been used so much for inexpensive bike stems.
>
> Hm. I thought the most fundamental issue, expense-wise, was the cost of
> the tooling and the equipment. Forging stamps are expensive, and the
> tooling is expensive too, because it has to be very strong, and probably
> has a shorter service life than an equivalent casting.
>
For die casting the costs for dies or molds can be quite expensive
compared to the cost of forging dies because they are generally made to
produce more accurate parts with mimimal additional work required.
> The finishing is surely a factor, though.
The cost savings with castings has a lot to do with the reduced need for
secondary machining and finishing operations.
Chas.
|
| | | | | | |
Date: 25 Sep 2007 19:24:31
From: still me
Subject: Re: Forged vs. ?
|
On Tue, 25 Sep 2007 11:38:51 -0700, "* * Chas"
<verktygjunk@aol.spamski.com > wrote:
Follow up question... in the days of yore, a blacksmith would
repeatedly pound the part (iron or steel) into shape. It seems to me
(intuitively) that this would tend to arrange the steel in a much more
ordered fashion than simply hitting it with a massive multi-ton press
just once. Or maybe in the multi-ton, he parts that actually get
formed into a bend would pick up strength, but the parts that are left
unbent would not gain strength.
Comments?
|
| | | |
Date: 24 Sep 2007 09:54:03
From: Mike Jacoubowsky
Subject: Re: Forged vs. ?
|
> That said, many items are forged, but don't say that they are. I would
> think that just about all the stems you will meet would be forged, but I
> am sure that there are exceptions if they are particularly old.
I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
we had "forged" and "melt-forged" stems, the "melt-forged" versions being
less-expensive and, according to SR and Shimano, were forgings done at
higher temperatures and not as strong as a lower-temp (room temp?) forging.
I never looked into it beyond such claims; others here will know if this is
actually true or not.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
|
| | | | |
Date: 25 Sep 2007 01:37:23
From: Jasper Janssen
Subject: Re: Forged vs. ?
|
On Mon, 24 Sep 2007 09:54:03 -0700, "Mike Jacoubowsky"
<mikej1@ix.netcom.com > wrote:
>I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
>we had "forged" and "melt-forged" stems, the "melt-forged" versions being
>less-expensive and, according to SR and Shimano, were forgings done at
>higher temperatures and not as strong as a lower-temp (room temp?) forging.
>I never looked into it beyond such claims; others here will know if this is
>actually true or not.
'Cold-forged' steel AFAIK just starts at room temp, after being
spectacularly deformed under massive pressure, it heats up to "can burn
you" levels at least, when it comes out of the process.
Drop-forged, as seem on many wrenches (especially cheap ones), AFAIK
involves using a Very Big Hammer (several tons of weight) which fall from
a height onto the steel and shape it that way, in one go. I think those
typically hot-forge.
Jasper
|
| | | | | |
Date: 24 Sep 2007 22:15:56
From: A Muzi
Subject: Re: Forged vs. ?
|
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>> I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
>> we had "forged" and "melt-forged" stems, the "melt-forged" versions being
>> less-expensive and, according to SR and Shimano, were forgings done at
>> higher temperatures and not as strong as a lower-temp (room temp?) forging.
>> I never looked into it beyond such claims; others here will know if this is
>> actually true or not.
Jasper Janssen wrote:
> 'Cold-forged' steel AFAIK just starts at room temp, after being
> spectacularly deformed under massive pressure, it heats up to "can burn
> you" levels at least, when it comes out of the process.
>
> Drop-forged, as seem on many wrenches (especially cheap ones), AFAIK
> involves using a Very Big Hammer (several tons of weight) which fall from
> a height onto the steel and shape it that way, in one go. I think those
> typically hot-forge.
Have you seen a 5 or ten ton forge? It drops. That's what it is/does.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | |
Date: 27 Sep 2007 01:22:21
From: Jasper Janssen
Subject: Re: Forged vs. ?
|
On Mon, 24 Sep 2007 22:15:56 -0500, A Muzi <am@yellowjersey.org > wrote:
>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>> I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
>>> we had "forged" and "melt-forged" stems, the "melt-forged" versions being
>>> less-expensive and, according to SR and Shimano, were forgings done at
>>> higher temperatures and not as strong as a lower-temp (room temp?) forging.
>>> I never looked into it beyond such claims; others here will know if this is
>>> actually true or not.
>
>Jasper Janssen wrote:
>> 'Cold-forged' steel AFAIK just starts at room temp, after being
>> spectacularly deformed under massive pressure, it heats up to "can burn
>> you" levels at least, when it comes out of the process.
>>
>> Drop-forged, as seem on many wrenches (especially cheap ones), AFAIK
>> involves using a Very Big Hammer (several tons of weight) which fall from
>> a height onto the steel and shape it that way, in one go. I think those
>> typically hot-forge.
>
>Have you seen a 5 or ten ton forge? It drops. That's what it is/does.
But on warm or cold steel?
Jasper
|
| | | | | | | |
Date: 27 Sep 2007 00:26:06
From: A Muzi
Subject: Re: Forged vs. ?
|
>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
>>>> I'm not a metallurgist (nor do I play one on the 'net), but back in the day,
>>>> we had "forged" and "melt-forged" stems, the "melt-forged" versions being
>>>> less-expensive and, according to SR and Shimano, were forgings done at
>>>> higher temperatures and not as strong as a lower-temp (room temp?) forging.
>>>> I never looked into it beyond such claims; others here will know if this is
>>>> actually true or not.
>> Jasper Janssen wrote:
>>> 'Cold-forged' steel AFAIK just starts at room temp, after being
>>> spectacularly deformed under massive pressure, it heats up to "can burn
>>> you" levels at least, when it comes out of the process.
>>> Drop-forged, as seem on many wrenches (especially cheap ones), AFAIK
>>> involves using a Very Big Hammer (several tons of weight) which fall from
>>> a height onto the steel and shape it that way, in one go. I think those
>>> typically hot-forge.
> A Muzi <am@yellowjersey.org> wrote:
>> Have you seen a 5 or ten ton forge? It drops. That's what it is/does.
Jasper Janssen wrote:
> But on warm or cold steel?
I'm sorry I was a bit terse. When a chunk of steel gets smashed with a
few tons in a forging die, it comes out hot. Very hot.
If you start with a red-hot piece, the required impact to get grain
alignment is less (as with hammer and tongs and a fireplace).
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | |
Date: 24 Sep 2007 22:32:53
From: * * Chas
Subject: Re: Forged vs. ?
|
"A Muzi" <am@yellowjersey.org > wrote in message
news:13fgv9am2trdge2@corp.supernews.com...
> > "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote:
> >> I'm not a metallurgist (nor do I play one on the 'net), but back in
the day,
> >> we had "forged" and "melt-forged" stems, the "melt-forged" versions
being
> >> less-expensive and, according to SR and Shimano, were forgings done
at
> >> higher temperatures and not as strong as a lower-temp (room temp?)
forging.
> >> I never looked into it beyond such claims; others here will know if
this is
> >> actually true or not.
>
> Jasper Janssen wrote:
> > 'Cold-forged' steel AFAIK just starts at room temp, after being
> > spectacularly deformed under massive pressure, it heats up to "can
burn
> > you" levels at least, when it comes out of the process.
> >
> > Drop-forged, as seem on many wrenches (especially cheap ones), AFAIK
> > involves using a Very Big Hammer (several tons of weight) which fall
from
> > a height onto the steel and shape it that way, in one go. I think
those
> > typically hot-forge.
>
> Have you seen a 5 or ten ton forge? It drops. That's what it is/does.
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
Here's a virtual tour of a forge plant that I visit frequently. The ground
shakes when they are working with their 12,000 ton steam powered hammer.
http://www.berkforge.com/tour.html
Here's another one:
http://www.coulter-forge.com/photogallery/photo.html
Chas.
|
| | | | |
Date: 24 Sep 2007 12:46:22
From: * * Chas
Subject: Re: Forged vs. ?
|
"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote in message
news:MYRJi.551$yc5.24@nlpi069.nbdc.sbc.com...
> > That said, many items are forged, but don't say that they are. I would
> > think that just about all the stems you will meet would be forged, but
I
> > am sure that there are exceptions if they are particularly old.
>
> I'm not a metallurgist (nor do I play one on the 'net), but back in the
day,
> we had "forged" and "melt-forged" stems, the "melt-forged" versions
being
> less-expensive and, according to SR and Shimano, were forgings done at
> higher temperatures and not as strong as a lower-temp (room temp?)
forging.
> I never looked into it beyond such claims; others here will know if this
is
> actually true or not.
>
> --Mike-- Chain Reaction Bicycles
> www.ChainReactionBicycles.com
>
"Melt forged" was/is a BS term for injection molding, a method for making
high quality castings. The first time I saw the term used was on the
Sugino Maxi cranks that had the chainrings swaged onto the crank arm.
A casting is still a casting and doesn't have the benefits of increased
metal density that comes from forging.
Chas.
|
| | | | | |
Date: 24 Sep 2007 15:22:07
From: A Muzi
Subject: Re: Forged vs. ?
|
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote
>>> That said, many items are forged, but don't say that they are. I would
>>> think that just about all the stems you will meet would be forged, but
> I
>>> am sure that there are exceptions if they are particularly old.
>> I'm not a metallurgist (nor do I play one on the 'net), but back in the
> day,
>> we had "forged" and "melt-forged" stems, the "melt-forged" versions
> being
>> less-expensive and, according to SR and Shimano, were forgings done at
>> higher temperatures and not as strong as a lower-temp (room temp?)
> forging.
>> I never looked into it beyond such claims; others here will know if this
> is
>> actually true or not.
* * Chas wrote:
> "Melt forged" was/is a BS term for injection molding, a method for making
> high quality castings. The first time I saw the term used was on the
> Sugino Maxi cranks that had the chainrings swaged onto the crank arm.
> A casting is still a casting and doesn't have the benefits of increased
> metal density that comes from forging.
Later development by SR-Sakae, Shimano and Sugino advanced that process
greatly and to good effect. Low price, good finish, reasonable weight
and excellent track record. At the SR-Sakae Tokyo plant, where I spent
quite a bit of time, every single piece was fluoroscope inspected and
the failure rate was extremely low. Mr Kobayashi's process used a 4-ton
ram to fill molten aluminum through a tree with quick-change modular
product tooling.
The original Maxy was a ground breaking 'proof of concept' product, but
much effort was expended after that to improve the material, design and
process. Today's stems, shock fork bottoms, cranks etc directly benefit
from that work.
We beat this to death on r.b.t. about the semantics of 'cast', 'forged',
'melt-forged', 'thixoformed' etc but the end result is a workable
midprice product with dependable performance.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | |
Date: 24 Sep 2007 22:34:36
From: * * Chas
Subject: Re: Forged vs. ?
|
"A Muzi" <am@yellowjersey.org > wrote in message
news:13fg71dn4cm4d2e@corp.supernews.com...
> > "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote
> >>> That said, many items are forged, but don't say that they are. I
would
> >>> think that just about all the stems you will meet would be forged,
but
> > I
> >>> am sure that there are exceptions if they are particularly old.
> >> I'm not a metallurgist (nor do I play one on the 'net), but back in
the
> > day,
> >> we had "forged" and "melt-forged" stems, the "melt-forged" versions
> > being
> >> less-expensive and, according to SR and Shimano, were forgings done
at
> >> higher temperatures and not as strong as a lower-temp (room temp?)
> > forging.
> >> I never looked into it beyond such claims; others here will know if
this
> > is
> >> actually true or not.
>
> * * Chas wrote:
> > "Melt forged" was/is a BS term for injection molding, a method for
making
> > high quality castings. The first time I saw the term used was on the
> > Sugino Maxi cranks that had the chainrings swaged onto the crank arm.
> > A casting is still a casting and doesn't have the benefits of
increased
> > metal density that comes from forging.
>
> Later development by SR-Sakae, Shimano and Sugino advanced that process
> greatly and to good effect. Low price, good finish, reasonable weight
> and excellent track record. At the SR-Sakae Tokyo plant, where I spent
> quite a bit of time, every single piece was fluoroscope inspected and
> the failure rate was extremely low. Mr Kobayashi's process used a 4-ton
> ram to fill molten aluminum through a tree with quick-change modular
> product tooling.
>
> The original Maxy was a ground breaking 'proof of concept' product, but
> much effort was expended after that to improve the material, design and
> process. Today's stems, shock fork bottoms, cranks etc directly benefit
> from that work.
>
> We beat this to death on r.b.t. about the semantics of 'cast', 'forged',
> 'melt-forged', 'thixoformed' etc but the end result is a workable
> midprice product with dependable performance.
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
That's interesting, thanks for the info.
My objection is to the term "melt forged". Call it a high precision
casting or something similar.
Chas.
|
| | | | | | | |
Date: 25 Sep 2007 06:06:12
From: jim beam
Subject: Re: Forged vs. ?
|
* * Chas wrote:
> "A Muzi" <am@yellowjersey.org> wrote in message
> news:13fg71dn4cm4d2e@corp.supernews.com...
>>> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote
>>>>> That said, many items are forged, but don't say that they are. I
> would
>>>>> think that just about all the stems you will meet would be forged,
> but
>>> I
>>>>> am sure that there are exceptions if they are particularly old.
>>>> I'm not a metallurgist (nor do I play one on the 'net), but back in
> the
>>> day,
>>>> we had "forged" and "melt-forged" stems, the "melt-forged" versions
>>> being
>>>> less-expensive and, according to SR and Shimano, were forgings done
> at
>>>> higher temperatures and not as strong as a lower-temp (room temp?)
>>> forging.
>>>> I never looked into it beyond such claims; others here will know if
> this
>>> is
>>>> actually true or not.
>> * * Chas wrote:
>>> "Melt forged" was/is a BS term for injection molding, a method for
> making
>>> high quality castings. The first time I saw the term used was on the
>>> Sugino Maxi cranks that had the chainrings swaged onto the crank arm.
>>> A casting is still a casting and doesn't have the benefits of
> increased
>>> metal density that comes from forging.
>> Later development by SR-Sakae, Shimano and Sugino advanced that process
>> greatly and to good effect. Low price, good finish, reasonable weight
>> and excellent track record. At the SR-Sakae Tokyo plant, where I spent
>> quite a bit of time, every single piece was fluoroscope inspected and
>> the failure rate was extremely low. Mr Kobayashi's process used a 4-ton
>> ram to fill molten aluminum through a tree with quick-change modular
>> product tooling.
>>
>> The original Maxy was a ground breaking 'proof of concept' product, but
>> much effort was expended after that to improve the material, design and
>> process. Today's stems, shock fork bottoms, cranks etc directly benefit
>> from that work.
>>
>> We beat this to death on r.b.t. about the semantics of 'cast', 'forged',
>> 'melt-forged', 'thixoformed' etc but the end result is a workable
>> midprice product with dependable performance.
>> --
>> Andrew Muzi
>> www.yellowjersey.org
>> Open every day since 1 April, 1971
>
> That's interesting, thanks for the info.
>
> My objection is to the term "melt forged". Call it a high precision
> casting or something similar.
>
> Chas.
>
>
the material is a slurry of solid particles with just a little
interstitial liquid at the time of forming. like ice slush in a
slurpee. it's definitely not "casting" in any traditional sense.
|
|
