Lightweight Manufacturing Aluminum Body Structure

Definition of automobile lightweight

Using modern design methods and effective means to optimize the design of automobile products or use new materials, under the premise of ensuring the comprehensive performance index of automobile, to achieve the comprehensive index of weight reduction, energy saving, emission reduction and safety.

Lightweight technology path:

Three aspects: design, materials and manufacturing process.

1. Structural optimization design is the basis and premise. Through the design, the materials, the optimal structural shape and size are used in the appropriate position, so that each part of the materials can play the maximum load-bearing role and improve the utilization rate of materials.

2. New materials for weight reduction, including lightweight materials such as aluminum alloy, magnesium alloy, titanium alloy, plastic, porous foam and plastic composites, and high strength materials such as high strength steel.

3. New forming manufacturing process refers to the technology to meet the needs of high-strength materials application and parts integrated design. At present, laser tailor welded blanks, hot stamping, flexible pressing, rolling forming, micro foaming, semi-solid forming, hydroforming and connection technology are widely used.

Lightweight is the trend of the times. However, the use of aluminum alloy and other lightweight materials can not fully represent the degree of lightweight of a car. Lightweight is a system engineering. Only through the continuous optimization of the structural system, with appropriate materials, and appropriate cost control, can we build a truly acceptable lightweight car.

What is "all aluminum body"?

"Body" refers to the main frame structure of the body, also known as "body in white". Do not confuse the body in white with the body panel, because the body panel generally refers to the parts on the surface of the vehicle, such as the door, front and rear covers and fender“ "All aluminum" in "all aluminum body" refers to that the main material of BIW is aluminum alloy, and some important structures in BIW that affect collision safety will still use high-strength or ultra-high strength steel, that is to say, "all aluminum body" actually belongs to steel aluminum hybrid body. Therefore, "all aluminum body" made of 100% aluminum alloy does not exist in mass production vehicles.

Advantages and disadvantages?

Three advantages:

1. Lightweight. All aluminum is at least 100kg lighter than traditional steel. Improve power performance, fuel economy and handling.

2. Corrosion resistance. The durability is higher than steel.

3. Safer. The energy absorption of aluminum is twice that of steel.

There are two disadvantages

1. High cost. Aluminum and steel aluminum welding and stamping process is very difficult. At present, the welding process includes riveting, screw connection, resistance connection and laser connection. However, the toughness of aluminum plate is poor, and the precision of stamping equipment and process is required to be high.

2. High maintenance cost.

Fuel economy calculation

If the vehicle weight is 2500kg and the aluminum alloy weight is 750KG, the vehicle weight will be reduced by 30%, so the fuel consumption will be reduced by 7% * 30 / 10 = 21%. Take changing cars in 10 years as an example, the average annual mileage is 10000 miles, so the total mileage in 10 years is 100000 miles, and the fuel consumption is saved by 1E5 * 21% / 30mpg = 700 gal. Now the oil price is $3 per gallon, saving a total of $2100. If the average price of the car is set at $20000, the ratio of fuel cost to car price will be about 10%.

Performance requirements of aluminum plate:

1. Good formability: low yield ratio and high forming limit

2. Surface smoothness: avoid slip line

3. Good weldability: failure resistance

4. Good bake hardenability: the yield strength increases obviously after stamping and baking

5. Good chemical conversion performance of zirconate and titanate