Aluminum alloys

You don't say what actual usage you have for these pincer arms.

Without seeing your existing arms,and knowing the usage requirements, it is not easy to assist you better.

Rather than aluminium alloys, perhaps you should be looking for titanium, which gives greater strength for around the same weight as aluminium alloy - Thus the arms could be of less mass - designed slimmer in cross-section etc.

Dependent on usage, (please advise further) the titanium could be fabricated, forged, or cast.

Titanium would be far more expensive than aluminium alloy, of course.

Well the problem there is Cost I am trying to keep them marketable! The producct is a beadbreaker for commercial tires, see at www.tirespyder.com!

thank you!

Thank you I will talk to my foundry, By the way, the cross section is roughly 2" x 2" in an I-Beam shape tapering down to Approx. 1.375" (including Plastci guard) x 6".

I've looked at:

www.tirespyder.com

The type of usage shows that aluminium or other soft alloys would not stand up to the work required.

Because the work done by these arms is heavy work, often by persons who are relatively unskilled, the ductile iron is a better choice for the arms material.

Apart from the lower cost of the ductile iron, that material stands up to the required heavy work far better than a lighter softer alloy.

Yes but the weight issue is still prevailent to the handling of the BeadBreaker shaving 20 or so lbs off the unit is highly desirable.

I can see where you are coming from.

Ductile Iron = cheap, will stand up to the arduous nature of the work, but is heavy.

Aluminium alloy = More expensive, physically larger than the iron one, to obtain the same strength, is too soft to handle the arduous work over a long period.

Titanium = Very expensive, smaller in size than aluminium alloy, but larger than iron, will wear faster than iron, but wear far less than aluminium alloy.

If cost was no problem, make the arms from titanium, with chrome/vanadium end attachment jaws, or hard chrome plate the titanium jaw ends, so you get the low wear at the jaws, with high strength and lightness of the titanium arms.

Some truck parts have been sucessfully replaced using cast 6061 and heat treated to T6. you do not specify a duty so it hard to give a difinitive answer

good luck

Phil

Current arm strength has a failure point of 14,000lbs on short side of fulcrum and 7,000 lbs on long side of fulcrum in contact with tire. But this is largely excess strength as the ram has a max power curve of 10,000lbs with just 5,000lbs at the tire as the fulcrum has a roughly 2 to 1 energy loss. Product testing over 5,000 or so tires has shown no tire bead has required more than 3,800lbs of force at the ram to break the bead.

P.S what about almag alloys, how do they stack up.

Hi,

if no corrosive environment there you should try Al 7075.

It is used for high strength applications. (airplane landing structures)

I would not recommend temper T6 but prefer T7 or T73 or T76 as these conditions are much more stable.

With this material you can do a 1 to 1 replacement of your parts but attach some tips as recommended above.

If you need the same elastic properties you will have to change the shape as elastic modulus of Al-alloys is a factor of 3 lower than of Fe-alloys.

RHABE

Suggest you consider A201 cast Aluminum - available from most foundries as sand, plaster or investment casting. Very good castability, with the yield/tensile properties of mild steel. The existing part in ductile iron was no doubt cast, therefore pattern equipment probably exists - but the difference in shrinkage would provide somewhat different dimensions. Examine the source of the existing part, then discuss with the foundry.