Manufacturing Aluminum Masts

Sprayed on?

YES after all there being sold for Yachts.

FF

 

I was looking at this: http://www.ihpva.org/com/PracticalInnovations/materials.html

Now someone said that most masts are produced from 6061-T6, now the process for this is to Solution heat treated and artificially aged. Is done on the extruded section or is this done when in billet form?

 

The reference in your link refers to heat treating after welding "Additionally, 6061 T6 losses half its total strength when welded. Consequently, a post heat treatment process is required to regain it's full T6 strength." An earlier post mentioned that the extrusion was tapered by cutting out a portion and then closing the sides together in order to weld the section back together.Perhaps if you add the heat treatment stage between items 3 and 5 in the list in post No 9 the process will be in the correct order.

 

The mast builders I have worked with had no ability to heat treat after welding, they just welded the slit up and ground and painted.

The boats we built were all CRUISERS , not racers , so the weight aloft was gladly carried for the extra strength.

FF

 

Thanks for your responses, the size of these factories must have been huge!

 

Do you have to stretch them to straighten the mast out once extruded? or is this not needed?

Thanks

 

Also what defects or quality checks have to be made?

 

I would also like to know and you are the expert, please Fred

Mikey

 

for what it is worth , the T6 is done after, but unless there are tests done and mill certs issued one can not always be sure of the temper, for instance I took delivery of 3 tonnes, flat bar for stringers in small ships, when we tried to form them for bending, they cracked--too brittle fortunately I picked this up early and the factory took it all back. they had just issued the mill cert without tests
Thsi may explain why yacht mast collapse in column for no apparent reason
T6 with form well look at the frames in my gallery, all t6 T section
i have not been following, but a crowd in Bris Aust imports section from China now. there is huge profit in it, the cost may be as low as 5 a kilo, and sold as a mast section for huge profit, 30 a kilo?

 

What do you mean the T6 is done after? An how?

 

First it is squeezed through the die, then heat treated
there is a raft of data, here is one link, try google heattreating to t6http://www.suppliersonline.com/propertypages/6061.asp

 

Hmmm, Ok, with that I have added that they are heat treated and quenched after the extrusion process... this correct?

1. Aluminum 6061 Billets are melted down and extruded through the mast cross section die.
2. Then it is heat treated and quenched.
3. The extrusion is then cut to the length required.
4. The top end would be cut and tapered and welded.
5. Any other holes and fixings would be cut out.
6. The mast would then be anodized.
7. Mast would be prepped (alodine wash, zinc chromate primer, undercoat, LP paint).
8. Final finish coat applied: Awlgrip.
9. Any screw holes chased.

 

yes , cept if its anonized you would,nt paint
And you dont need case threads
By the way the only stuff that will last in Ally threading, is a stuff called lanacoat, made from natural sheep oil, its thick and smell of well sheep, and it stays there forever, we used it always and screws come out easily with it years down the track. It is a NZ product, so don't ask me where you will get it
Are you building sticks?
if youa remember try not to weld AROUND the section, particularly in the lower panel,

 

What quality control checks are carried out?

 

Is not the welding going to destroy the annealling? I suspect that this is the order that is practiced, but the heat treatment must be performed after the welding, if the mast is really T6. Otherwise, 6061T6 is just a starting material and the mast is not T6. Right?