[TowerTalk] galvaniizing heat treated steel

[SPWoo]

Good questions Jim.  I called the tube supplier and they told me the tube is stress relieved but not quenched as in traditional heat treatment.  The 'SR' designation in the description denotes stress relieve.  I did a google on 4130 stress relieve and it appears it's done at about 1200F.  Hot dipped galvanizing is done at 830F.  I did some research on galvanization of high strength steel and it appears that the process is highly dependent on the chemical composition of the steel.  Steels with yield strength higher than 150ksi encounters 'hydrogenembrittlement'.  To get an answer on this from an expert I sent an e-mail to a person at the American Galvanizers Associastion at the recommendation of my galvanizing supplier.  My galvanizing supplier uses the same process for all steels with yield strength less than 150ksi.  For steels more than 150ksi they use a different process.


You are correct if some of this is overkill.  In my case I do get a lot of wind here and I'd rather be safe than sorry.  Another local ham lost an antenna with the same mast that the 4130 replaced. That mast is the M15R sold by US Towers.  The material for that mast is low carbon structural steel with a yield strength of only 36kpsi.  For me it's better safe than sorry.  73.


Best Regards,
Jonathan Woo, W6GX
(970) 646-1711