Extract from “Newsletter of Aluminium Fabrication Industry & Market”
Aluminium in the Transportation Sector
In light of the better performance that aluminium contributes to automobiles, the consumption of aluminium in automobiles has increased gradually in the past five decades and has replaced cast iron (gear boxes and transmission cases), low carbon steel (bodies and wheels) and copper (heat sinks). The application of aluminium in automobiles is traditionally in the form of casting. In recent years, engineers have gradually developed other aluminium products applicable for automobiles, such as extrusion and stamping parts. In addition, the use of forged components is increasing in automotive chassis and suspension systems, shock resistance as well as other structural applications.
In Europe, over 20% of the hoods for automobiles are made of aluminium including those for many family cars such as the Peugeot 307. The body of the Jaguar XJ was the first one made of aluminium based on the design of aluminium sheets with the use of structured adhesive technology as one of its connecting methods. The bodies of several other high-performance sports car brands, such as Ferrari and Lotus, are also made of aluminium.
Aluminium increases the carrying capacity of trucks and hence lowers the frequency of transportation and eventually carbon dioxide emission. Currently, the roofs of most of the tankers and tank semi-trailers are made of aluminium. Also, aluminium is often used in the bodies of trucks and (automated) dump trucks. Taking an articulated truck as an example, the use of aluminium components can reduce the deadweight of the truck and trailer by up to 2 tons. As a result, an aluminium-intensive truck can carry more goods within its weight limit given its lightweight advantage.
The use of aluminium can increase the capacity of passenger carriages in addition to many other advantages. Aluminium can be extruded into complex forms for sophisticated design and structures which require high strength tolerance. A modern passenger carriage with an aluminium body is several hundred kilograms lighter than a traditional carriage, and within the maximum gross weight limit; carriages made of aluminium can carry more passengers and hence transportation costs can be reduced. The above advantage is more obvious in passenger carriages running long distance routes and stopping frequently at public stations.
Zhengzhou Yutong Bus Company, the world's second largest passenger carriage manufacturer, introduced two types of environmentally friendly carriages in 2008. The body weight of the new aluminium-intensive carriages was around 46% lighter than the traditional ones, fuel consumption and greenhouse gas emission decreased accordingly as a result.
The introduction of aluminium to railway/subway trains made lower operating costs possible. In the 1960s, aluminium was used in the cog railway market, and in the 1980s, aluminium became the preferred metallic material for rural transportation and high-speed rails due to the low operating costs and improved acceleration performance. Thanks to the application of aluminium in rail transportation, high-speed double-deck trains were developed in 1996. This kind of train is speedy and optimizes the transportation capacity, with its weight 12% lighter than the single-deck train while passenger capacity increases by 40%.
Railway once referred to as "the road of iron." Nowadays, many countries are operating metros or trams with aluminium carriages, some examples are the Powertrain in Canada, the high-speed electric double-track rail in France as well as the Hikari Rail Star (Shinkansen bullet train) in Japan; many load-bearing components and bodies of these trains are made of aluminium. Due to the application of aluminium, it is possible to boost the train speed to over 350 km/h. In Western Europe, every four out of five metro and intercity rails’ carriage bodies are made of aluminium. Thus, it could be more appropriate to describe the current status of railway transportation as "the road of aluminium”.
Aluminium Plays a Key Role in Promoting Green Development
According to a research study conducted by the International Energy Agency (IEA), about 20% of interviewees believed that greenhouse gas emissions come from the transportation sector. As a result, weight reduction of transportation vehicles has become one of the most important ways to improve fuel efficiency, reduce energy consumption and greenhouse gas emissions. Of course, other measures such as improving engine performance, reducing air resistance and the development of better lubricants are also helpful.
Greenhouse gas emissions related to transportation reaches 76 million tons every year. According to the conclusion suggested by a study conducted by Helms and Lambrecht in 2004, assuming all transportation vehicles (including road vehicles, rail vehicles and aircrafts) were designed under the direction of lightweight development without changing their performance, 6.6 million tons of greenhouse gas emissions could be reduced.
The life-cycle of an automobile consists of three independent phases: production, consumption and retirement. Due to the recyclable nature of aluminium, the above life-cycle can be described as "from cradle to cradle" rather than "from cradle to grave". Energy consumption and the corresponding carbon dioxide equivalent emission are the largest during consumption phase, while the emissions during production and retirement stages account for less than 20% of the total carbon dioxide output. Thus, energy saving measures should focus on the consumption phase of the vehicles’ life- cycle.
In 2006, global production of passenger cars and light trucks amounted to 65 million. The use of aluminium reduced global carbon dioxide equivalent emission by 14 million tons. The amount of total energy saved due to the use of aluminium during their product life-cycles was equal to 550 million liters of crude oil.
The introduction of aluminium into the transportation sector has made a significant contribution to the development of lightweight land and sea transportation vehicles, and this trend will continue. The transportation sector’s demand on aluminium has increased annually. In 2005, around 30% of the global aluminium consumption came from the transportation sector. In 2000, the aluminium content per vehicle was only between 100 and 120 kg, and the amount increased to between 110 and 145 kg in 2006.
In order to achieve lightweight development by replacing heavier materials, the aluminium industry has been striving to develop and optimize the components for transportation vehicles so as to reduce fuel consumption and greenhouse gas emissions, and aluminium components have been used as replacement parts in various transportation vehicles. Each type of component has undergone life-cycle analysis in order to obtain information on energy savings and greenhouse gas emissions during each component’s life-cycle.
The life-cycle model developed by the aluminium industry is applicable to all transportation vehicles including automobiles, trucks, trains and vessels. The model’s result is calculated with production, consumption and recycling information of aluminium available to the public with reference to the life-cycle assessment principles and the information related to energy and greenhouse gas emissions covered by the international standard ISO 14044.
(Editor's Note: On July 15, 2011, China Zhongwang, the world's second-largest, China and Asia's largest developer and manufacturer of industrial aluminium extrusion products announced new development progress for its new aluminium flat rolled business. The Group will set up a production base in phases with planned total capacity reaching 3 million tons, and it will rank the Group on top of the global list by planned capacity and product positioning. Aluminium flat rolled products, i.e. the aluminium sheet project, are mainly used in sectors including aviation and aerospace, vessels, rail transportation etc. The move of China Zhongwang is to meet the strong demand from the global transportation industry, and the new business will become a strong growth driver for the Group.)
