Peter Cole said:jim beam said:Peter Cole said:jim beam wrote:
> Peter Cole wrote:
Quoted message said:Quoted message said:>>>> Vacuum degassing was big news in the 50's. It's a cheap bulk
>>>> process, common as dirt. What else have you got?
>>>
>>> it's /cheaper/ than it was, but it's still expensive.
>>
>> No, it's not.
>
> er, it is actually.
>
>
>>
>>> and it didn't
>>> start being used for bike spoke material until the 70's
>>
>> Cite, please. It was used in auto sheet metal by that time.
>
> not even in the 80's big guy. that's the last time i went through a
> strip mill and it was either open ingot or con-cast. look at this
> stuff
> under a microscope some time and you'll see the evidence for yourself.
Used by the Japanese for auto bodies in the 70's. US by 80's, little
man. How can this be "expensive" if it's used in massive quantities
in cars?
but wasn't! not for bulk sheet. maybe you're thinking of oxygen
lancing?
http://en.wikipedia.org/wiki/Basic_oxygen_steelmaking
No. From that article (did you read it?):
"The first basic oxygen steelmaking process was the LD process developed
in 1952 by voestalpine AG in Linz, Austria. Some major steelmaking
companies in the US did not convert to this process for decades, with
the last Bessemer converter still operating commercially until 1968.
The LD process replaced both the previously common Siemens-Martin
process, also known as the open-hearth process, and the Bessemer process."
As you should know, vacuum degassing is not related to the "LD" process
which is merely an upgrade to the original Bessemer process, using
oxygen instead of air.
not only did i read it, i've done it. and it's the process that
produces the majority of the material used in bulk product like sheet,
rod, bar, etc. used today. the product is good enough that you don't
need to worry too much about additional refining unless you have a
special use.
Quoted message said:
As for vacuum degassing (your magic process)
<http://www.memagazine.org/backissues/membersonly/april98/features/vacuum/vacuum.html>
"Vacuum-degassing systems, which are all customized, fall into two
categories. The first type, RH recirculating degassers invented by
Heraeus-Rheinstahl in Germany, involves inserting two legs, or snorkels,
of a vacuum chamber into a ladle of liquid steel. The metal is drawn
into the chamber via one snorkel that injects argon to promote
turbulence; it is then exposed to the vacuum to remove gases and
recirculated back through the other snorkel. The other system, a tank
degasser, is a vessel into which the ladle is sent and stirred by the
injection of argon. The chamber is depressurized to remove gases, and
finally the ladle is removed."
As for the timeline:
"Cramb noted that automakers' demand for ultralow-carbon sheet steel to
make lightweight but durable car panels for more-fuel-efficient cars has
been the major factor driving vacuum degassing's growing share of the
sheet-steel market in the later 1980s and early 1990s.
"One plant has been making over 1.2 million tons of degassed sheet steel
to supply the automotive market" out of an annual production of 6
million tons, according to Ron Holmes, a metallurgical engineer and
senior process consultant at Kvaerner Metals, a subsidiary of Kvaerner
ASA in Oslo, Norway. Kvaerner Metals has designed and installed numerous
vacuum-degassing systems for processing sheet steel for automotive end
users.
"Although this is a relatively new story in the United States, dating
from the late 1980s, Japanese steel makers were degassing sheet metal
for autos at least 10 years earlier,""
ok, first, 10 points for producing an interesting article for once.
second, if you read further, you'll see that it gets slightly more
specific about the product this material is used to produce. this may
indeed be used in some sheet used in vehicles, but price alone prohibits
it being used for the majority - it would only make sense for some
chassis componentry and other fatigued components like suspension and
engine bolts. and even then, not every manufacturer would be
interested. it would be great for forged cranks for example, but the
majority of producers cast cranks because it's so much cheaper - fatigue
benefits of superior materials be hanged.
as for chronology, the benefits have been known for a long time - since
the 30's i believe, but knowing about it, being able to produce it, and
/paying/ for it are all completely different things. i don't believe
that an auto industry that will save 6' of copper wire by using the same
bulb for brake lights and turn signals, or not using washers/gaskets on
spark plugs, has the /slightest/ interest in paying extra for vacuum
degassed steels when cheap cast iron [censored] will do.
