[TowerTalk] Yield strength data for plain steel water pipe
Robin E. Midgett
rmidgett@bellsouth.net
Wed, 03 May 2000 20:26:27 -0500
Thanks very much for posting this info. Sometimes the most useful
information is of that which is useless!
It looks to me that some of the API grades may be worth looking into for
price vs. other mast materials.
At 11:20 AM 5/2/2000 -0400, Mark . wrote:
>Greetings gang,
>
>I did some more digging on the strength properties of water pipe, to help
>us select and size it for mast use more effectively. NOTE: I am not
>referring to structural tubing, which is a completely different class of
>higher-quality and stronger steel. Here's what I found out.
>
>Water pipe is no longer made from wrought iron, it is all wrought steel,
>since the 70's. Any 'scheduled' water pipe you buy new should be wrought
>carbon steel.
>The 'jackpot' reference table is in the American Society for Metals
>handbook, volume 1, eighth edition, page 149.
>
>The pipes are made to ASTM or API specifications, with corresponding
>sub-grades, which should be marked on your pipe if it is new, so you can
>positively identify the grade and strength.
>
>The most common, and lowest grade of pipe is ASTM grade A120, welded or
>seamless pipe, back or galvanized. It's material composition *is not
>controlled at all* !!!!
>
>****
>Specification A120 does not specify or require a minimum yield strength
>(page 146). All that is required is that it pass a hydrostatic pressure
>test! Wow, this is unbelievable. It is used "...for all ordinary purposes
>such as conveying fluids under low pressure..." For this reason alone, I
>would not recommend grade A120 at all. Check the markings. This is crap
>steel! One can only guess that it has close to the lowest strength of the
>other types, *at best*. Now we know where all the recycled steel from
>those AMC Pacers went to! Hee hee hee <*grin*>
>****
>
>NOTE: the strengths are *yield* strength (not tensile strength), which is
>the point where the material will first start to bend permanently.
>Stainless steel pipe is different, and I will post that data when I find it.
>
>Match up the mill markings on the pipe itself (best), or if new, refer to
>the vendor's specification/certification.
>
>MINIMUM YIELD STRENGTHS FOR:
>COMMON SCHEDULED WATER PIPE TYPES
>Carbon (plain) steel, black or galvanized
>
>ASTM TYPES
>A120, no sub grade .... ??? pot luck
>A53, grade A ......... 30,000 psi
>A53, grade B ......... 35,000 psi
>A106, grade A ......... 30,000 psi
>A106, grade B ......... 35,000 psi
>A106, grade C ......... 40,000 psi
>A135, grade A ......... 30,000 psi
>A135, grade B ......... 33,000 psi
>A139, grade A ......... 30,000 psi
>A139, grade B ......... 35,000 psi
>A333, grade C ......... 30,000 psi
>
>API TYPES
>5A, grade F-25 ........ 25,000 PSI
>5A, grade H-40 ........ 40,000 PSI
>5A, grade J-55 ........ 55,000 PSI
>5A, grade N-80 ........ 80,000 PSI
>5A, grade P-105 ....... 105,000 PSI
>5A, grade P-110 ....... 110,000 PSI
>5A, grade D ........... 55,000 PSI
>5A, grade E ........... 75,000 PSI
>5L, no grade given .... 25,000 PSI
>5L, class I ........... 25,000 PSI
>5L, class II .......... 28,000 PSI
>5L, class A ........... 30,000 PSI
>5L, class B ........... 35,000 PSI
>
>
>As you can see, the strengths can vary considerably, but if you have
>scheduled water pipe that you cannot positively identify, don't assume a
>yield strength higher than 25,000. And that's with no safety factor.
>
>This material is so commonly available, it can be quite suitable for
>masting, when you select the grade and size it properly. But just remember
>that is the the weakest grade of steel there is, so size your application
>carefully.
>
>Sorry if this seems like too much detail, but this information is crucial
>to being sure that your mast is strong enough.
>
>I frequently get chided by friends for whipping out the pencil and
>calculator to 'run the numbers'. I admit! My 'nerd watch' has a calculator
>in it. :)
>
>But, when you do it right, you sleep at night (especially during storms).
>
>Hope this has helped someone. From what I have read here, there's little
>worse than trying to replace a bent mast on a tower.
>
>Good luck!
>
>--...MARK_N1LO...--
>________________________________________________________________________
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>
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73,
Robin E. Midgett KB4IDC EM66se
rmidgett@bellsouth.net
1/2 of the Award Winning NT4L Rover Team
http://www.almostanywhere.com/vhf/vhf.html
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