Re: [TowerTalk] 4130 Chrome-Moly Grades

["D. Scott MacKenzie" <kb0fhp@comcast.net>]

Regarding the 4130 grades - most have not been heat treated.  Most have
simply been normalized.  I asked several, and they all replied that they
hare normalized, and not heat treated.  However, you can get heat treated
4130, or have it heat treated.

Based on the yield strengths of the material, it was determined, for my
application, that 1026 DOM would suffice, with adequate safety factor.

Scott
  -----Original Message-----
  From: Ron Hylton [mailto:ad7l@hevanet.com]
  Sent: Tuesday, August 01, 2006 2:05 AM
  To: kb0fhp@comcast.net
  Subject: Re: [TowerTalk] 4130 Chrome-Moly Grades


  Hi Scott,

  I hope you don't mind if I ask you a follow-up question.....

  Do you think that the masts that are available from the amateur radio
suppliers, like Texas Towers, Array Solutions, etc., have been heat treated?
I sort of doubt it, but I'm curious what you think.

  Best regards,
  Ron AD7L

    ----- Original Message -----
    From: kb0fhp@comcast.net
    To: Ron Hylton
    Sent: Thursday, July 13, 2006 9:00 AM
    Subject: Re: [TowerTalk] 4130 Chrome-Moly Grades


    Ron:

    I meant to include the message to the whole group - but I only hit
reply, instead of reply to all - could you forward to the group?

    Thanks

    Scott

      -------------- Original message --------------
      From: "Ron Hylton" <ad7l@hevanet.com>

      > Hi Scott,
      >
      > Thanks for your response. If I am reading your response correctly,
are you
      > saying that if I bought this tube, I would then have to arrange for
heat
      > treating, and that it is not ready to use "off the shelf" (of course
it
      > would need to be galvanized, too.)
      >
      > Thanks,
      > Ron
      >
      > ----- Original Message -----
      > From:
      > To: "Ron Hylton" ;
      > Sent: Thursday, July 13, 2006 6:29 AM
      > Subject: Re: [TowerTalk] 4130 Chrome-Moly Grades
      >
      >
      > > Depending on the specification: Condition N is normalized and
ready to be
      > heat treated. CDSR is stress-relieved. More than likely the material
is in > a form similar to hot rolled, and not normalized for uniform
microstructure.
      > It is heated to some nominal temperature to relieve any stresses
from the
      > manufacturing process. The final commercial grade is an unknow, but
I would
      > suspect that it is simply as-received from the mill. It would be in
a
      > microstructure similar to a hot rolled microstructure. However, all
these
      > grades can be heat treated to fairly high strength and toughness -
and would
      > yield (excuse the pun) excellent results. Another big difference
between
      > the grades is the amount of testing done - the AMS grades require
more
      > testing, but the alloy chemistry is essentially the same. There may
also be
      > some difference in the inclusion content which would affect fatigue
life and
      > impact strength.
      > >
      > > As a metallurgist, I would feel comfortable with using any of the
grades,
      > especially if they were he at treated appropriately. The best is
probably
      > the airframe grade, followed by the aircraft grade, and finally the
      > commercial grade. For the purpose of mast materials, the service is
      > relatively low, with failure usually being overload instead of
fatigue. Any
      > one of them would work....
      > >
      > > Hope that helps
      > >
      > > Scott, KB0FHP
      > >
      > > -------------- Original message --------------
      > > From: "Ron Hylton"
      > >
      > > > Here in the Portland metro area, we have an excellent source of
tubing
      > from
      > > > a company called Tube Service. They offer several grades of 4130
alloy
      > > > Chrome-Moly tube, including:
      > > >
      > > > 4130 Airframe (Cond. N) Specs: Mil-T-6736, AMS 6360
      > > > 4130 Aircraft (CDSR) Specs: AMS-6371
      > > > 4130 Commercial Specs: ASTM A-519
      > ; > >
      > > > My question is, which grade is typically used for masts?
      > > >
      > > > 73,
      > > > Ron AD7L
      > > > Hillsboro, Oregon
      > > >
      > > >
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      >
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