Background

Recent widespread publicity on the increasing use of light metals in the transport sector replacing steel has possibly overlooked the tried and proven technology of forging aluminium in a wide range of applications. It is clear that some of the emerging casting technologies deserve close examination when considering fabrication options available to the designer, however the characteristics of a relatively simple forged design often provide the desired weight + strength at low cost. These characteristics are clearly understood by some Australian automotive suppliers, as some new products are planned to be introduced in the near future with forged aluminium as the preferred means of fabrication. It is worth reviewing why.

Strength

When forged and heat treated, the light (SG=2.7) and common aluminium alloys exhibit some mechanical properties comparable with many grades of steel. (SG=7.8). The strength to weight ratio is therefore far superior. For example, the alloy 2014-T6 has a typical UTS of 485MPa, exceeding that of many grades of steel, and all commonly used Al and Mg casting alloys. Unlike some casting processes, forging is always porosity free thus allowing relatively straight forward heat treatment processes that significantly improve selected mechanical characteristics. The lower cost 6061 Al attains typical values of 310MPa, which is also superior to, for example, A356 (or 601 type) Al casting alloy whether that alloy is semi-solid cast, squeeze cast or gravity cast. Further fabrication by welding is also available with 6061 aluminium, opening the opportunities for many other applications.

This strength comparison is only on the published data, and so what is not being reviewed is the clear advantage forged aluminium exhibits over all other wrought product, when the forging has been designed to provide optimum grain structure to suit the application. A combination of hot and cold working the alloy can allow strength considerably in excess of the “typical value”, allowing a single process to greatly assist both static and fatigue test results, and so should be considered when assessing a new application.

Surface Finish

A wide range of surface finishes can be produced with forging, from very smooth surfaces to relatively sharp serrations, and this may facilitate further surface finishing or be a functional attribute of the part design. Some alloys, like 6061, have desirable anti-corrosion characteristics without any further surface treatment at all.

Design & Material

Only extremely high-grade, aerospace-quality 6061-T6 materials are used in the manufacturing process.

State Of The Art Forging

Unlike many manufacturers that use turn-of-the-century casting techniques, American Force uses only state-of-the-art forging processes to make its wheel centers.

This results in:

High Load Capabilities

One of the biggest benefits of the forging process (pressurizing metal to increase its density), is that it results in predictable strength properties that have less porosity and fewer inclusions. This means your American Force Wheels give you high load capabilities.

Built-in Reliability

Another benefit of forging is the hot working that refines the material's grain pattern and imparts high strength, ductility and resistance properties. This means your American Force Wheels are extremely reliable.

Excellent Dimensional Stability

One of the biggest benefits of radial forging is that it allows for alignment of the concentration of the material strength in the direction of the load. This means that cuts are made with the grain not across it. And that means your American Force Wheels are very rigid

and exceptionally strong.

STRONG, RELIABLE, STABLE, BALANCED, CONSISTENT & EXTREMELY LIGHT-WEIGHT.

Aluminum Wheels

Even though steel wheels are more affordable, aluminum wheels are more popular. Aluminum wheels are only one third as dense as steel wheels making them lightweight and strong. Braking distances decrease while acceleration goes up, so aluminum wheels can actually improve the safety of your car, truck, or SUV.

There are two types of aluminum wheels - Cast aluminum wheels and Forged aluminum wheels.

Cast aluminum wheels are formed by pouring molten aluminium into a one-piece mold. The casting process produces better consistency between sizes and lines from one wheel to another which can provide a smoother ride and less wear on your tires than steel wheels with hubcaps.

The manufacturing process for forged aluminum wheels is even more stringent. Forged wheels are produced by applying extremely high force to the base wheel material in a contained die. The high-pressure stamping process is critical to forged aluminum wheel strength because there are less cracks, abrasions, and grain imperfections.

How to Care for Aluminum Wheels

Custom aluminum wheels can help Increase or maintain the resale values of your car, truck, or SUV. Take care of your investment in custom aluminum wheels by following some basic care instructions.

• Regularly remove dirt and debris from aluminum wheels using mild soap and water

• Apply wheel polish to aluminum wheels regularly, but make sure to buff it out thoroughly

• Balance, rotate, and align aluminum wheels on a regular basis

• Do not have aluminum wheels steam cleaned

Manufacturing

Cast wheels are formed by pouring molten aluminum into a mold and machining the bolt-holes and flanges into spec. Forged wheels are formed by hammering hot or cold steel into shape between a set of dies.

Molecular Grain

Cast wheels have a uniform grain, where the molecules sit on top of each other and are held together by mechanical adhesion (like a bowl of cooked rice). Forged wheels have an interlocking grain structure that is more difficult to pull apart (like a bowl of spaghetti).

Metals

Most cast wheels use A-356 aluminum, which is only about 60 percent as strong as the 500 or 6000-series alloys used for forged wheels.

Weight

While the weight of forged and cast wheels is almost equally dense, the stronger nature of the forged aluminum means that wheels made in that manner require less material to maintain the same rigidity.

Cost

The only advantage that cast wheels have over forged units is that they're 25 to 50 percent cheaper.

Applications

Forged wheels are recommended for use in all low-profile tire applications (2.5 inches of sidewall or less). Potholes, curbs and road debris can easily bend cheap cast rims.

Rinse the aluminium with water. You can use a high pressure cleaner to remove dirt and light grease deposits

While the aluminium is still wet, spray the cleaner evenly onto the surface.

Allow the cleaner to work on the surface for 10 to 15 minutes. The aluminium will become shiny white.

Rinse the cleaner off the aluminium with sufficient water. Repeat if required. Stubborn deposits can be removed with a scourer.

Polished Aluminum Wheels

Polished aluminum wheels are very popular, particularly with racing, off-road and hot rod enthusiasts, and we sell thousands of them each year, however, they do require more periodic maintenance than other finishes, depending upon the climate, road conditions and your vehicle car care practices in general. Polished aluminum alloy wheels require the highest degree of maintenance and a certain amount of oxidation is to be expected as the wheels naturally oxidize with age. Polished wheels can be re-polished commercially or by hand after many years of use, effectively restoring them to an almost factory original condition.

If they are in bad condition, this will take some time, and polishing wheels is never an easy task.

For faster and perhaps easier results, use a Dremmel-type tool mini-polisher, with the correct polishing mini-pads. Just swab on Polish, then buff them with the polishing tool. Mini power tool polishers will clean up and polish your wheels quickly, saving time and producing a brilliant shine.

If your wheels have deeply imbedded brake dust, animal urine or other contaminants from lack of maintenance, you can try an aggressive spray-on wheel cleaner (be careful, some contain acid) with a brush,

BUT DO NOT ALLOW IT TO SIT ON THE SURFACE AND ETCH THE POLISH SURFACE. Rinse your wheels thoroughly and dry with soft, non-abrasive cloth.

We receive many inquiries about clear coating or chrome plating polished aluminum wheels, as a maintenance option. If you are interested in applying a permanent protective coating to your polished aluminum alloy wheels, you may wish to consider taking the wheels to a local wheel reconditioning or chrome plating firm in your area. This service involves professionally polishing and applying a liquid or powder coat acrylic or polyester clear coat or chrome plating the wheels.

Services of this type can be found under "wheel reconditioning" or "chrome plating" in the Yellow Pages or on the worldwide web.

Polished Wheels Look Great, But Do Require Regular Maintenance.

POLISHING COMPOUND

Contains Finest Abrasives

A premium composition for the finest finish on gold, silver, etc. Skillful buffing with this will bring out all the beauty of the natural color in any metal. Use on flannel buff.

BUFFING

For good buffing results, follow the few simple but important steps below. First, let's get acquainted with some of the buffing terms commonly used:

A SECTION OR SINGLE BUFF

Consists of layers of material sewed together in various ways. It is usually about 1/4 inch thick at the face.

A BUFFING WHEEL

Consists of one or more single sections. You can buy ready made multiple buffs, which are single sections sewed together, or you can assemble any thickness buffing wheel you wish by putting together single or multiple buffs on your spindle. Buffing wheels should always be mounted on your spindle between flanges firmly gripping the sides.

FLANGES

Are the metal discs between which buffing wheels are mounted. Each wheel is supplied with a pair of special toothed flanges which bite into the buffing wheel to prevent it from slipping.

THE FACE OR EDGE of a buffing wheel is the working surfaces.

PREFACED, means that the trued wheel face has a soft nap which prepares it for easy applications of compositions.

A COMPOSITION, OR COMPOUND,

Is the material applied to the face of a buffing wheel to enable you to obtain the finish you desire. It consists of abrasives, which do the work, held in suspension by wax or grease, which acts as a binder to hold the abrasive to the buff. There are many kinds of compositions, ranging from coarse cutting emery to the finest jewelers' rouge', and each has a particular use. Buffing wheels will not product results without compositions.

SPINDLE SPEED

is the speed of your spindle expressed in R.P.M., or revolutions per minute.

SURFACE SPEED, or S.F.P.M., is the speed at which the face of your buffing wheel travels, as distinguished from the spindle speed of your buffing or polishing head. S.F.P.M. is an abbreviation meaning Surface Feet Per Minute. It is important that you know the S.F.P.M. of your wheel, as it should be varied to obtain the best results for coarse buffing cutting down, or coloring. For best results, your wheel should maintain a S.F.P.M. at 3,600-7,500. The higher the speed the better and quicker the results. Formula for calculating S.F.P.M. is S.F.P.M.=1/4 diameter of buff multiplied by the spindle speed in R.P.M. Thus, an 8" wheel @ 3,600 R.P.M. =2 x 3600 R.P.M. or 7200 S.F.P.M.

COARSE BUFFING

Means buffing with coarse compositions, such as emery, to remove rust, grinding marks, and rough surface imperfections.

CUTTING DOWN

Means buffing with sharp cutting compositions, such as Tripoli and Stainless, to remove additional surface imperfections and give a moderate luster.

COLORING

Means the final buffing, which is done with various softer or finer compositions to bring out the natural color or luster of the material. Most polishing projects will require more than one buffing operation in each of the above classes. You may find it advisable in some instances to color, or even to cut down, with two or more compositions or with the same composition on different type buffing wheels in order to obtain the result you desire.