Malakka wrote: it all in the subject line
Thus, 08 Jul 2004 09:11:54 GMT
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Nobody. You can obtain 4130A but not 4130N. Some aircraft manufacturers
are obtaining A and having it heat treated to N. Which from a
metallurgical point is a waste of time and money. 4130N is no longer N
after it is welded, but the parts were certified with N and it is just
easier to treat it themselves.

The last steel company producing N sheet went bankrupt and no one else
has stepped up to the plate to set up production. Some thicknesses are
still available in Normalized condition.

If the completed part is going to be heat treated after fabrication it
makes no difference whether you start with A or N. And there are few
cases where you weld fabricate a part and use it as-welded where it
makes any difference either.
--
Bruce A. Frank
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Aircraft Projects
Fuel Tank Fabrication
TIG, MIG & Oxy/Acet Welding & Brazing