Technical Report The Construction of Alloy Wheels

2086 Words5 Pages

Technical Report The Construction of Alloy Wheels

Introduction

Aluminium alloy wheels are now used in all branches of Motor Racing,

ranging from Touring cars and Rally cars to Formula One cars. The

Alloy wheels offer far superior mechanical properties than the

conventional steel wheels formerly used. These benefits include

reduced un-sprung weight, i.e. not held by the suspension, providing

more precise steering input and improved responsiveness.

Alloy wheels also improve acceleration and braking due to the

reduction of weight. The added strength of a quality alloy wheel can

significantly reduce wheel/tire deflection in cornering. This is

particularly critical with a vehicle equipped with high performance

tires where lateral forces may approach 1.0g. The metals in alloy

wheels are excellent conductors of heat - improving heat dissipation

from the brakes - reducing risk of brake fade under demanding

conditions. Additionally, alloy wheels can be designed to allow more

air to flow over the brakes, this can help cooling.

The alloy used in the finest road wheels today is a blend of aluminium

and other elements. The term "mag wheel" is sometimes incorrectly used

to describe alloy wheels. Magnesium is generally considered to be an

unsuitable alloy for road usage due to its brittle nature and

susceptibility to corrosion.

Nowadays, there are basically three ways in which alloy automotive

wheels are constructed. The three types can be referred to simply by

cast, billet and forged.

Casting is a relatively inexpensive way to produce a high-quality,

fairly strong alloy wheel; many aftermarket alloy wheels designed for

street use are made this way. Billet wheels are machined from a solid

chunk of material and forging uses intense heat and pressure to

transform a slug of alloy material into the final shape of a wheel.

This report will focus mainly on the casting processes used.

Casting Processes

The most common process of constructing alloy wheels is One-Piece

Casting, there are a number of methods to do this, and the most basic

is Die Casting, this process is used world wide throughout the casting

industry and is not exclusive to alloy wheels.

The Die Casting process uses a permanent mould usually made of metal,

which generally means that there is high tooling costs compared to

other methods of casting, but this high tooling cost is combined with

low production costs. This means that die casting is suitable for

products with a large production number.

There are four main processes in the die casting family, these are:

Gravity Die Casting

Pressure Die Casting

Low Pressure Die Casting

Squeeze Casting

Gravity Die Casting

This process is the most simple of the four, the mould or die, which

is generally made in two halves, is filled with molten metal, in the

More about Technical Report The Construction of Alloy Wheels

Open Document