[TowerTalk] Chromoly(4130) Strength Information

[Dick Weber]

Chromoly 4130 Masts -- Important Information

	I've been seeing the messages about 4130 masts and have noticed that an important piece of information has not been discussed which may have an effect on those whow are contemplating buy such material from a supplier or surplus house.

	Most 4130 when bought new is in a condition called "Normalized." In this condition the yield strength is 75,000 psi and the ultimate is 95,000 psi. It is sold this way so the user can work it (machine it for example) more freely. To develop its highest strength it is then heat treated. This will take it to a yield to over 100,000psi and the ultimate to over 125,000 psi. If you are possibly going to buy some 4130 make sure you know if it's "Normalized" or "Heat Treated."  All the surplus 4130 I've seen has been was normalized. If it's normalized, don't buy it unless you're going to get it heat treated, because the 1040 steel masts sold by Texas Towers are about 10,000 psi stronger than normalized 4130 and they are galvanized. 

73,

Dick, K5IU, PE
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Yes.  4130 is the usual grade for "chromoly".


N6TT@worldnet.att.net on 04/15/97 12:52:13 PM

To:   towertalk@contesting.com
cc:    (bcc: Tyler G Stewart/BENN/CEC)
Subject:  [TowerTalk] Chromoly(4130)




After calling a dozen tubing companies in LA, I found a place that has 500
foot of chromoly 2" O.D. .250 wall, ranging from 17-24 foot. My question is
they all said there material is 4130 grade, is this standard? Cant seem to
find any other grade...
    Steve N6TT@worldnet.att.net




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