New Energy Vehicles Encourage Forging Aluminum Wheels to Prosper

The rapid development of the new energy automobile industry has driven the development of the domestic forged aluminum alloy wheel industry. China's aluminum wheel market has good prospects and has great potential.

First, forging aluminum alloy wheel market to follow the demand arising from the development of new energy vehicles

As the demand for energy saving and consumption reduction of automobiles keeps rising, safety and environmental protection regulations are increasingly stricter, and the requirements for vehicle weight reduction are more urgent. Aluminum alloy is of light weight, high strength, good formability, and high recovery rate. It is of great significance for reducing auto weight, saving tires, reducing fuel consumption, reducing environmental pollution, and improving operational performance. It has become the first choice for the automotive industry; forging aluminum alloys. Wheels are also favored, especially new energy cars!

China's new energy automotive industry began in the early 21st century. In 2001, the research project of new energy vehicles was listed in the “863” major scientific and technological topic during the “Tenth Five-Year Plan” period of the country, and a strategy for starting from the petrol car to the goal of hydrogen-powered vehicles was planned. Since the "Eleventh Five-Year Plan", China has put forward the strategy of "energy-saving and new energy vehicles". The government pays close attention to the research and development and industrialization of new energy vehicles.

In 2008, new energy vehicles have shown a comprehensive attack in the country. In 2008, it became China's "new energy vehicle first year." In January-December 2008, sales of new energy vehicles increased mainly due to the growth of passenger vehicles. In January-December, 899 units of new energy passenger vehicles were sold, an increase of 117% year-on-year, and a total of 1,536 new energy vehicles sold by commercial vehicles were sold. The installation rate of forged aluminum alloy wheels is only less than 0.01%.

In 2009, with the introduction of intensive support policies, China’s new energy vehicles have entered a rapid development track. Although the proportion of new energy vehicles in China's auto market is still minimal, its growth potential in China's commercial vehicle market has begun to release. The installation rate of forged aluminum alloy wheels is about 0.05%.

In 2010, China is stepping up efforts to support new energy vehicles. New energy vehicles are entering the phase of full-scale policy support; the installation rate of wrought aluminum alloy wheels is about 0.07%.

From 2011 to 2015, it entered the stage of industrialization and promoted new energy, urban passenger cars, hybrid power, and pure electric vehicles in the whole society; the installation rate of forged aluminum alloy wheels has so far been about 32%; the installation rate of wrought aluminum alloy wheels in the heavy truck market is also It reached 18%.

Second, the reason why the forged aluminum alloy wheel project thrives depends on the characteristics of forging aluminum alloy wheels

Comparison of forged aluminum alloy wheels and ordinary truck hoops:

1. It is light. The weight of the forged aluminum ring is only equivalent to one-half the weight of the iron ring, taking 22.5X8.25 as an example; the forged aluminum ring is 24 kg and the iron ring is at least 48 kg.

2. Save fuel. After installing a forged aluminum ring, due to the reduced weight of the vehicle, the rotational inertia of the wheel is reduced, the acceleration performance of the vehicle is improved, and the demand for braking energy is accordingly reduced, thereby reducing the fuel consumption, and the air that is unique to the forged aluminum coil. Flow and rolling resistance, so the 100km test saves at least 2 litres of oil per 100km (The 100km fuel consumption after replacing forged aluminum rings and air conditioners is lower than that for forged aluminum rings without air conditioning. The former is lower than the latter. Lower 2.5 liters of fuel consumption).

3. Tire wear reduced by 26%. Due to the characteristics of the forging ring, its balance value is 0, it is not easily deformed, and the dispersion temperature is fast (the normal running temperature is 20-30 degrees lower than the iron ring). The protection of the suspension system is better, so the wear of the tire is greatly reduced, so that Each tire runs 50-80,000 kilometers more.)

4. The maintenance cost of brakes is reduced. Due to the fast dispersion of the characteristics of the forged aluminum ring and the low normal driving temperature, the material and the accessories that are not resistant to high temperatures in the braking system have excellent protection effects, thereby greatly reducing the maintenance cost of the braking system.

5. The bearing capacity is high, and the carrying capacity of the forged ring is 5 times that of the ordinary iron ring. Forged wheels were deformed by 5 cm after they took 71200 kg. The iron ring has been deformed by 5 cm after only 13600 kg. In other words, the strength of the forged rim is more than 5 times that of the steel wheel.

6. Lightweighting brings better benefits Take the 40-ton semi-trailer of a fleet of Wuxi-Xiamen freight lines as an example. The car has 22 wheels. After the use of aluminum alloy wheels, the vehicle weight is reduced by 528 kg or more. . Calculated according to the transport cost of 0.5 yuan per ton of road, the mileage from Wuxi to Xiamen is about 1200 kilometers. The daily transportation income of the vehicle can increase by 316 yuan, and the annual increase can be calculated by 300 days and the annual increase can reach 94,800 yuan. Subtracting the one-time investment in aluminum wheels, the actual increase in profits for the year was also over 61800 yuan.

7. Aluminum wheels have high recycling value. A 24kg aluminum alloy wheel has a recycling value of 250 yuan.

8. Reduce carbon emissions.

(1) Reducing carbon dioxide emissions during production: The carbon emissions from the production of 1 ton of steel are 1700 kg; and the carbon emissions from the production of 1 ton of aluminum is 1500 kg. Based on the calculation of carbon emissions in the production process, the carbon emissions from the production of a 23kg aluminum wheel can be reduced by 87.4kg compared to the 46kg iron wheel.

(2) Reducing fuel consumption and reducing carbon emissions: Calculated at 1,000 kilometers per day, 1,000 kilometers/day x 2.5 liters (lower fuel consumption per 100 kilometers) x 300 days x 0.785 kg (carbon emissions per liter of fuel) = carbon reduced annually 5887kg of emissions.

Third, the forging process of aluminum alloy wheels and casting process aluminum alloy wheels - the old and new alternating period

1, aluminum alloy wheel material

A356 is a cast aluminum alloy, which is an Al-Si-Mg alloy. Due to the large amount of Si (6.5-7.5%), A356 aluminum alloy has good liquidity and comprehensive casting properties. However, the impact properties of such aluminum alloys are also reduced. Cast aluminum alloy wheels are produced using such aluminum-silicon-magnesium alloys.

6061 alloy is a kind of deformed aluminum alloy, which is usually called forgeable aluminum alloy. Because there is no requirement for its liquid flowability, its solid deformation requirements are relatively high, so its Si content is 0.4-0.8%. Therefore, its impact resistance is much stronger than that of the A356 cast aluminum. Most forged aluminum alloy wheels are forged with 6061 alloy.

2. The production process of aluminum alloy wheels can be divided into casting, forging and manufacturing methods between casting and forging.

(1) Aluminum wheel casting process (Liangfeng, Wanfeng, Shuguang, Daika, Yueling, Shenlika, etc. adopt this process)

A356 aluminum alloy melting - degassing - pouring - molding - T6 heat treatment - machining - surface treatment.

The process of gravity casting aluminum wheels is to cast the molten aluminum liquid from the gate on the mold directly into the mold for cooling and molding. This casting method is simple and the mold cost is low. However, the pouring riser is relatively large, and the aluminum material consumes a large amount; the gas and impurities are easily entrained during casting, and the flow rate and temperature stability are poor. Therefore, casting defects are relatively large. Tilt weight casting developed on this basis can reduce these defects.

The low-pressure casting aluminum wheel technology is in the aluminum liquid holding furnace under the mold, and the aluminum liquid is directly injected into the rim model through the liquid raising pipe through a liquid raising pipe, and the principle is similar to the pneumatic type hot water bottle. In this way, the temperature and speed are stable, and gases and impurities are not brought into the mold. Therefore, there are fewer casting defects. Due to the fact that there are almost no feeders, the aluminum material is less expensive. Based on this, differential pressure casting and atmosphere protection casting can be developed to minimize casting defects.

(2) Manufacturing process for forging (CITIC Dicar, Deka Hongxin, Jiangsu Perran Forging, Gude Mg-Al, Zhengyu Aluminum Huaan Zhengxing, etc. adopt this process)

6061 aluminum alloy round bar - according to the weight of the blank cut into sections - heated to about 400 degrees - in the forging press more than 8,000 tons for 3 to 4 times the initial molding - strong spinning machine final cold spin molding - T6 heat treatment - machining - surface treatment.

The forged aluminum alloy has high density, grain refinement and fibrous structure, and its mechanical properties and strength such as hardness, tensile strength and yield strength are greatly improved. At the same time, defects such as looseness, porosity, and poor impact properties of cast aluminum alloys are avoided. Therefore, the mechanical properties of a forged aluminum alloy wheel of the same specification are about 30% higher than that of a cast rim, and the weight can be made about 20% lighter than the latter.

In addition, forged aluminum wheels contain less silicon than cast aluminum wheels and are denser. Therefore, forged aluminum wheels have better electrical and thermal conductivity than cast aluminum wheels. Therefore, forged aluminum wheels can be perfectly colored by anodizing; better thermal conductivity can reduce tire and brake system losses.

(3) Process between casting and forging

Squeeze casting (also known as forge forging), that is, after the completion of the casting pressurization in the mold, so that the grain refinement and increased density, increase strength and reduce weight. Casting plus spinning pressure is the use of casting blanks through the spinning machine to squeeze the rim of the tire ring, so that the tire ring part of the grain refinement and increased density, enhanced mechanical properties to reduce weight. There is also the so-called continuous casting and forging technique that has been invented in recent years in China. There is also semi-solidification forging abroad, and its technical difficulty and equipment requirements are very high.

However, Al-Si-Mg alloys are used in the manufacture of these aluminum wheels. Mechanical properties, especially impact properties, cannot be compared with forged aluminum alloy wheels.

Since aluminum hub production is a high-input, high-output industry, many companies have invested in the aluminum wheel industry for foundry processes.

Cast aluminum wheels are a kind of material-intensive and labor-intensive low-value-added products. In addition, aluminum casting is an industry that has pollution, high energy consumption, and poor working conditions for workers. Developed countries in Europe and America are currently Not interested, the aluminum wheel industry has gradually shifted to the Third World and purchased products directly.

China's casting process aluminum wheel product life cycle has entered a mature period, due to the casting process of aluminum wheel products in the introduction, growth and use a lot of time; relatively short mature, recession came earlier. In 2005, when aluminum wheels in China's foundry process entered the mature stage, the aluminum wheels forged in the forging process emerged quietly; a relatively healthy alternating old and new period was formed; the casting process used aluminum wheels for introduction and growth for nearly 20 years, while the forging process Aluminum wheels are only for 10 years, so forging aluminum wheels have a longer mature period of development conditions, aluminum wheels forging process is even more has a strong competitive advantage.

Fourth, prospects

Domestic aluminum wheel market competition is fierce, but according to the development of the automotive industry and foreign automakers in the domestic investment intentions, China's aluminum wheel market is still promising, there is still great potential. Exporting to foreign countries and developing the international market is also one of the major sales directions of aluminum wheel products in China. At the same time, the demand for aluminum wheel hubs for domestic automotive forging processes has also increased significantly.

Forging aluminum alloy wheels future development direction: engage in professional production, strengthen intellectual property rights, improve the excellent development ability, make forged aluminum alloy wheel products more refined, better; short 10 years of development witnessed China forged aluminum alloy wheels The road to development is based on the life cycle of the product (induction period, growth period, maturity period, and recession period). This is just the introduction stage. It has just entered the primary stage of the life of a forged aluminum alloy wheel, making the environment in China. With this big hand, the growth period will be greatly shortened and the period of maturity will reach a climax directly.

In 2015, the use of aluminum alloy wheels on commercial vehicles in China was based on the number of installations: Commercial vehicles wrought (cast) 460,000 aluminum alloy wheels, including commercial aluminum wheels made in China and imported into China. There are less than 80,000 pieces of aluminum alloy wheels forged in passenger cars, made in China and imported into China.

The statistics of 2016 work at the beginning of 2017 will reveal that the number of vehicles forged by aluminum wheels for commercial vehicles will increase by 35% and more than 45% for passenger vehicles. The statistics of 2017 work in early 2018 will reveal that the number of vehicles forged on aluminum alloy wheels for passenger vehicles for commercial vehicles will increase by 30% and over 40% on the basis of 2016.