Magnesium wheels

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Magnesium wheels are wheels manufactured from alloys which contain mostly magnesium. Magnesium wheels are produced either by casting (metalworking) (where molten metal is introduced into a mold, solidifying within the mold), or by forging (where a prefabricated bar is deformed mechanically). Magnesium has several key properties that make it an attractive base metal for wheels: lightness; a high damping capacity; and a high specific strength. Magnesium is the lightest metallic structural material available. [1] It is 1.5 times less dense than aluminium, so magnesium wheels can be designed to be significantly lighter than aluminium alloy wheels, while exhibiting comparable strength. Many competitive racing wheels are made of magnesium alloy. [2]

Contents

Cast magnesium wheels

Taking into account their generally inferior quality compared to forged wheels, the main advantage of cast wheels is the relatively low cost of production. And although cast wheels are more affordable than forged wheels, cast wheels are heavier than forged wheels for a given required load. Manufacturing defects found in cast wheels include cavities or porosity and a different metallurgical microstructure, entailing larger grain size. [3] Cast wheels will tend to fracture upon overbearing high-speed impact, whereas forged wheels will tend to bend. Diecast wheels continued to be used in elite racing such as Formula One, IndyCar, BTCC, MotoGP and World Superbike until mid 1990s, when forged wheel technology became preferred.

Forged magnesium wheels

Forged magnesium wheels are manufactured by mechanically deforming (forging) a prefabricated rod using a powerful forging press. Several somewhat different forging techniques exist, all of them comprising a multi-step process/operation. The resultant forging is subsequently machined (lathe-turned and milled) into the final shape of a wheel by removing excess metal from the forged blank. A forged magnesium wheel is 25 percent lighter than cast wheel. The main disadvantage of forged wheels is the high manufacturing cost. Owing to the typically high costs of finished wheels, forged wheels are still rarely purchased by non-professional drivers for regular road use.

But since forged wheels can be designed to be lighter than cast wheels for a given load, forged wheels do offer fuel economy and other distinct advantages. The forging process allows alignment of the metal fibers and optimization of the directional pattern arrangement along the spokes of a wheel. This, along with the smaller grain size, results in superior mechanical properties and performance characteristics that make forged magnesium wheels widely popular both for motor racing and with knowledgeable driving enthusiasts.

History

The original cast magnesium wheels were made beginning in the 1930s and their production continues today. Some of the biggest brands producing magnesium wheels in the past include Halibrand, American Racing, Campagnolo, Cromodora, Ronal, Technomagnesio, and Watanabe. The popularity of magnesium wheels peaked in 1950 -1960. Magnesium wheels from the middle of 20th century are now considered classic and are highly sought by some classic car enthusiasts. However, those magnesium wheels proved to be impractical because they were prone to corrosion and they were mostly used in racing sports. After 1960's magnesium wheels were gradually replaced by aluminium alloy wheels on the mass market, but not from the competition wheels market. Many manufacturers of magnesium wheels are still operating. A lot of companies continued production after the 1960s, although in lower quantities. Modern scientific and engineering developments led to significant improvements in the quality of magnesium wheels, including high-tech anti-corrosion treatment that extends the lifecycle of a wheel to match or even exceed the life cycle of comparable aluminium alloy wheel. Forged magnesium started to displace sand and gravity die-cast magnesium wheels in the mid-1990s. Up to the end of the 90s Marchesini, DYMAG and Marvic we supplying cast wheels to the elite motorbike racing market. DYMAG also supplied all the Lola and Reynard Indycars until 1998.

Common issues

A notable disadvantage historically affecting magnesium wheels was susceptibility to corrosion. Recent improvements in magnesium surface treatment technology have largely resolved the corrosion issues—to the extent that some manufacturers today offer a 10-year warranty.

A common misconception persists regarding the danger caused by magnesium's flammability. But new improved alloys have been developed over the past fifty years, with no reportable incidents of magnesium wheels catching fire. In fact, the U.S. Federal Aviation Administration has conducted wide-ranging tests over the past decade, concluding that the potential flammability of magnesium is no longer a concern—and even ruling to allow its use in aircraft cabins. [4]

With many challenges solved by modern technological solutions, a number of companies—including Brembo (Marchesini), BBS, OZ, Taneisya, and SMW Engineering—are now producing the next generation of reliable forged magnesium wheels. Additionally, several car and motorcycle manufacturers (Original Equipment Manufacturers, or OEMs) have successfully homologated forged magnesium wheels for use as original equipment. Only a limited number of forgers in the world have the large presses required to manufacture the forgings, from which forged magnesium wheels are machined.

See also

Related Research Articles

<span class="mw-page-title-main">Magnesium</span> Chemical element, symbol Mg and atomic number 12

Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals it occurs naturally only in combination with other elements and it almost always has an oxidation state of +2. It reacts readily with air to form a thin passivation coating of magnesium oxide that inhibits further corrosion of the metal. The free metal burns with a brilliant-white light. The metal is obtained mainly by electrolysis of magnesium salts obtained from brine. It is less dense than aluminium and is used primarily as a component in strong and lightweight alloys that contain aluminium.

<span class="mw-page-title-main">Duralumin</span> Trade name of age-hardenable aluminium alloy

Duralumin is a trade name for one of the earliest types of age-hardenable aluminium–copper alloys. The term is a combination of Dürener and aluminium. Its use as a trade name is obsolete. Today the term mainly refers to aluminium-copper alloys, designated as the 2000 series by the international alloy designation system (IADS), as with 2014 and 2024 alloys used in airframe fabrication.

<span class="mw-page-title-main">Forging</span> Metalworking process

Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer or a die. Forging is often classified according to the temperature at which it is performed: cold forging, warm forging, or hot forging. For the latter two, the metal is heated, usually in a forge. Forged parts can range in weight from less than a kilogram to hundreds of metric tons. Forging has been done by smiths for millennia; the traditional products were kitchenware, hardware, hand tools, edged weapons, cymbals, and jewellery.

Aluminium–silicon alloys or Silumin is a general name for a group of lightweight, high-strength aluminium alloys based on an aluminum–silicon system (AlSi) that consist predominantly of aluminum - with silicon as the quantitatively most important alloying element. Pure AlSi alloys cannot be hardened, the commonly used alloys AlSiCu and AlSiMg can be hardened. The hardening mechanism corresponds to that of AlCu and AlMgSi. The rarely used wrought alloys in the 4000 series and the predominantly used cast alloys are standardised in the 40000 series.

<span class="mw-page-title-main">Die casting</span> Metal casting process

Die casting is a metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity. The mold cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mold during the process. Most die castings are made from non-ferrous metals, specifically zinc, copper, aluminium, magnesium, lead, pewter, and tin-based alloys. Depending on the type of metal being cast, a hot- or cold-chamber machine is used.

<span class="mw-page-title-main">Foundry</span> Factory that produces metal castings

A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed.

<span class="mw-page-title-main">Pot metal</span> Alloy of various low-melting point, usually scrap, metals

Pot metal is an alloy of low-melting point metals that manufacturers use to make fast, inexpensive castings. The term "pot metal" came about due to the practice at automobile factories in the early 20th century of gathering up non-ferrous metal scraps from the manufacturing processes and melting them in one pot to form into cast products. Small amounts of iron often made it into the castings but never in significant quantity because too much iron would raise the melting point too high for simple casting operations.

<span class="mw-page-title-main">Rays Engineering</span> Japanese wheel manufacturer

RAYS Co., Ltd. is a high-end Japanese wheel manufacturer for both motorsport and street use. Their flagship brand, Volk Racing wheels, features a high-tech forging process exclusive to Rays Engineering.

<span class="mw-page-title-main">Magnesium alloy</span> Mixture of magnesium with other metals

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<span class="mw-page-title-main">Aluminium alloy</span> Alloy in which aluminium is the predominant metal

An aluminium alloy is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.

<span class="mw-page-title-main">BBS Kraftfahrzeugtechnik</span> Car wheel manufacturer

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<span class="mw-page-title-main">Alloy wheel</span> Wheel made from an alloy of aluminium or magnesium

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American Racing Equipment Inc. is a manufacturer of wheels sold via the aftermarket retail sector. Production started during the muscle car era in the United States. Platinum Equity investment group acquired American Racing Equipment Inc in June 2005.

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<span class="mw-page-title-main">Wobbly-web wheel</span>

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<span class="mw-page-title-main">Motorcycle wheel</span> Component of motorised two-wheelers

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<span class="mw-page-title-main">Wheel construction</span>

Wheel construction refers to the making of wheels. Construction of wire-spoked wheels is generally termed as wheelbuilding, so wheel construction refers to construction of non-wire wheels, e.g. wheels of cars and other heavier vehicles. Wheels are constructed in a wide variety of designs using different materials, but in the early 21st century, aluminum and steel are most often used, with steel-made wheels being heavier and more durable than aluminum wheels. The performance of a wheel depends on the alloy and technique used to construct it. A wheel is usually made up of a rim, which connects with the tire, and a central disc, also known as the disc or spider, which connects the wheel to the vehicle. Wheels are usually of two types: semi-drop center (SDC), used in trucks, and drop center (DC), used in other vehicles.

<span class="mw-page-title-main">Fuchs wheel</span>

The Fuchs wheel, or 'Fuchs felge', is a specialty wheel made for the first Porsche 911 model in the early 1960s. Designed in conjunction with Otto Fuchs KG, Porsche modeler Heinrich Klie and Ferdinand Porsche Jr for the 1967 model year Porsche 911S, the Fuchs wheel was the first light-weight forged wheel to be fitted to a production automotive vehicle. They provided the rear-engined sports car with a reduction in unsprung mass, using a strong and lightweight alloy wheel.

Aluminium–copper alloys (AlCu) are aluminum alloys that consist largely of aluminum (Al) and traces of copper (Cu) as the main alloying elements. Important grades also contain additives of magnesium and silicon, often manganese is also included to increase strength. The main area of application is aircraft construction. The alloys have medium to high strength and can be age-hardened. They are both wrought alloy. Also available as cast alloy. Their susceptibility to corrosion and their poor weldability are disadvantageous.

References

  1. "More than mag wheels". Cim.org.
  2. "Wheel rim". Formula1-dictionary.net. Retrieved 12 March 2022.
  3. Mintskovsky, Paul. "F1 Wheels". F1wheels.com.
  4. Timothy R. Marker. "Evaluating the Flammability of Various Magnesium Alloys During Laboratory- and Full-Scale Aircraft Fire Tests" (PDF). Fire.tc.faa.gov. Retrieved 2022-03-12.