This is a brief but informative file of cast versus forged wheels.

Attached Files

eTip16.pdf (466.9 KB, 7 views)

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2005 LE KC 4x2
A15 w/Steel, W07, N94, L92, Hellwig, Burtman SS Door Trim, Chrome Tailgate and Fog Lamp Trim, OEM Bug Deflector and Side Steps, Armada Air Dam, LED Brake/Taillights.

Thanks Flight, just the kind of info we are looking for. I recall a process that used a combination of the two processes. HIP, if my memory serves, Hot Isostatic Pressing. Where a casting is made and then surrounded by a rubber bladder and compressed at high temperature to compact and make the casting denser. Used on Titanium as I recall, because of the problems they were encountering with casting Titanium.

Red

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy

Very good.

Hot Isostatic Pressing (HIP) is a process that uniquely combines pressure and temperature to produce materials and parts with substantially better properties than other methods. The pressure medium is an inert gas, normaly Argon. Low temperature and high isostatic pressure, up to 300 MPa (3000 bar/44,000 psi), yield better controlled grain growth and structure as well as isotropic properties, which result in the superior performance characteristics typical for HIP'ed parts.

HIP applications include defect healing of castings, consolidation of metal powder (pre-form and near-net shaped parts), consolidation of ceramic powders, and sintering of diamond tools.

So on and so forth,

That was pretty trick. Thanks, always wondered about this.

Flight Test - what is your opinion on Centerline's rotary forged process and did you see this thread over at TT regarding failure of a Centerline wheel:

http://www.titantalk.com/forums/tita...re-w-pics.html ???

linky: http://www.centerlinewheels.com/technology.php

CENTER LINE'S ROTARY FORGED TECHNOLOGY
Patent # 4,936,129

Center Line has designed a rotary forging press, the only one of its kind in the world, to compress a solid billet of aluminum with 4,000 tons of force, at 300 revolutions per minute. Not only does this process rearrange the aluminum molecules, but it also aligns them in a circular pattern thereby adding strength. As a result, the rotary forged wheel has a much tighter grain structure and is significantly lighter weight than a cast wheel which requires greater mass due to its inherent porosity.

Read on to follow Center Line's patented manufacturing process and watch this solid 6061 aluminum billet be transformed into this striking one-piece rotary forged wheel. The following process takes place entirely at our factory in Santa Fe Springs, California.

1. The aluminum billet is run through the oven and heated to
900 degrees.


2. The nearly red-hot billets are transferred from the oven into the rotary forging press.


3. Spinning at 300 revolutions per minute, the billet is compressed into the die with 4,000 tons of force. This process forges the aluminum molecules into a tight grain structure arranged in a circular pattern thereby allowing Center Line to build incredibly light-weight, strong wheels.


4. The beginnings of a wheel in its forged state just as it is about to be removed from the rotary forging press.


5. Next, the aluminum forging must be split-spun to form the rim thereby completing the structure of a one-piece rotary forged wheel.


6. After the wheel is formed to proper dimensions, it is machined into one of Center Line's many popular designs.


David

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The 6000 series, specifically 6061, is a general purpose alloy. This is the least expensive and most versatile of the heat treatable aluminum alloys. It has very good corrosion resistance, finish-ability, excellent weld-ability, and a strength approximating that of mild steel. It anodizes nicely and is readily available. It is also used in tie rods, steering arms, bulkheads and tunnels, and some bumpers. If the part has been welded it should be heat treated to regain the strength it lost in the heat affected zone. Some parts made from 6061 seem like a good buy, but may not be strong enough.

Parts which are forged are formed by heating the metal, pouring it into a form or die, and using tremendous force. Forging actually compacts the molecules in the metal making it stronger. Basic rotary forging is a cold forging process done by hammering, using a series of dies and immense pressure resulting in extreme strength. Generally, a rotary forged part is the strongest available.
The final step in ensuring the strength of each part is the (computer controlled) heat treating process. In this process, the metal is heated to a high temperature, followed by cooling, the metal. This process not only strengthens the metal further, but relieves the stresses caused by welding.

The Centerline process seems to contain the steps to produce a high-strength part. I can't really comment on the wheel failure without examining it. I did not read the thread word for word. I believe one response said there was a sharp lip instead of a smooth contour, this could be a stress riser, possibly causing the failure. Was this particular wheel cast or forged? Too many variables involved. Have I dodged enough.

I wonder if there was a piece of scale that rolled into the metal during the rotary forging process?

Many times we've had barstock that is rejected, and some forgings too, for what we called "Non Metalic Inclusions", basicly some slag or scale got pressed into the metal. Now a magnetic particle inspection wouldn't work in aluminum, but a Dye Penetrent or Ulta-sonic test mint have shown the flaw during manufacturing and inspection. But, one has to wonder what form of Non Destructive Testing is performed to verify quality? Do they test each item, or statisticly sample each batch?
Be interested to find how this one turns out. I think if I had a good local lab, I'd have them look it over before it is returned to CenterLine. Send it back, and it will drop into the bottomless black pit. You'll only get the story they want you to have.

Red

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2005 Titan KC SE, Helwig, True-Track, ARE MX Canopy