By reducing the weight of the car, it can effectively reduce the emission of CO2 and so on, reduce the consumption of fossil fuels and raw materials, reduce the load of the suspension device, reduce the vibration intensity and improve the ride comfort, so the lightweight industry has become the development trend of the automobile industry. In a vehicle, the white body about 25% of the total weight, how to reduce the weight of the body is particularly important.

In order to meet the needs of the body lightweight, there have been Tailor Weld Stamping, hydraulic (pipe) molding and composite sheet forming and other new molding technology, there have been high-strength steel, aluminum and magnesium alloy and other new materials, there laser welding, Connection and other new connection technology. This paper focuses on the influence of laser tailor welding on the stamping, and its application in the lightweight body of the vehicle.

1 laser tailor welded blank

Laser Tailor Welded Blanks is a process in which two or more steel plates of different thickness or different materials are welded by laser to form a steel plate and then subjected to integral press forming. In the traditional white body manufacturing, the first need to punch a number of parts, and then welding the composition of the assembly, in many parts need to reinforce the plate parts. In contrast to this, there are a number of significant advantages to stamping steel plate stamping, in particular by reducing the number of workpieces, thereby reducing the processing links and reducing the cost of production.

Figure 1 shows the traditional production process and the laser tailor welding process comparison, compared to the advantages of laser tailor welding plate: reduce the weight of the workpiece, thereby reducing the weight of the vehicle; reduce the cumulative tolerance, the use of tailor-welded plate stamping, So that parts of a stamping, do not need to be a few parts welded into a part, greatly improving the accuracy of parts size; laser welding instead of traditional welding, the time can be a lot of savings, quality of welding to be improved; improve the safety performance of body collision, etc. The

Figure 1 Comparison of traditional production technology and laser tailor welding process

2 laser welding board of the main classification

1. Linear welds

Welds are straight, divided into continuous straight seam Welded blanket or non-continuous linear weld Tailor-welded blanks, linear weld laser tailor-welded blanks about 60% of the total amount of laser tailor-welded blanks.

2. Wirewound welds

Welds are broken lines, divided into continuous line welds Tailor-welded blanks (ie, chevron welds), non-continuous broken line Welded Welded Welded Blanket and Welded Welds Welded Welds Accounting for about 35% of the total amount of laser tailor-welded blanks.

3. Curve weld laser tailor welded blank

All or part of the weld for the curve, the curve of welding tailings laser welding plate about 5% of the total amount of laser welding plate.

The effect of stamping on the mold

The traditional mold is used to punch the sheet material thickness, material performance and so on a single homogeneous sheet. In the stamping of the steel plate, due to the various parts of the steel plate thickness, material properties vary, resulting in uneven drawing process blank deformation, weld displacement, to mold debugging has a great impact.

Therefore, in order to control the flow of metal, to minimize the displacement of the weld should follow the following principles:

1. In the design of welding steel plate, the development of stamping process to rational layout of the weld in the form and location, to choose the right base material, the appropriate sheet thickness.

2. In the mold debugging, the need for punch, die and blank holder to adjust. First reasonable layout of the extension of the bar, to control the flow of metal; the use of sub-valve-type blank holder, so that different parts of the welding steel plate by different blank holder force.

3. The use of multi-cylinder partial pressure control blank holder force.

4 application of laser tailor welded blanks

With the progress of technology, Welded steel plate has been widely used in the automotive industry, welding steel plate has been used in the body longitudinals, skeleton, floor, door panels, side and bumper and other parts (see Figure 2).

Figure 2 the application of welding steel plate in the body

At present, the medium and high-end car body has been widely used laser tailor-welded blanks; joint venture car car models on the laser welding blanket plate with its parent company (or joint venture partners) original model design. (Such as FAW Toyota Crown, FAW-Volkswagen Golf); some non-critical welding parts may change the design, instead of equal thickness plate (such as FAW - and so on), but the overall investment control, part of the welding pieces may still be CKD imports (such as FAW Toyota Crown, FAW - Volkswagen Golf) Volkswagen Audi A6 L's threshold plate).

The domestic automobile factory has also begun to use the laser welding parts in the body, and has formed a mature and convenient laser tailor-welded blanks supply network, such as Baosteel Group has been in the north, the eastern and southern established three laser tailor sheet processing and distribution center, And its further plans in Chongqing and Wuhan to build two laser tailor welded blanks processing and distribution center. Of course there are other manufacturers also have in the domestic production and distribution, such as ThyssenKrupp's Wuhan production base. In short, the domestic automobile stamping die factory already has a wealth of processing laser welding pieces of stamping die experience.

In the future, laser tailor welded blanks in the white body of the application will be more and more.

Dongguan City is letter Laser Technology Co., Ltd.

(Technology Engineering)