How to judge the quality of a car's sheet metal parts?

2022-11-29 08:40:52

In general, we can judge from two aspects: body and surface covering parts. Let's talk about it one by one, but one thing needs to be noted. Here are the methods that you can use when you go to the 4S store as an ordinary car buyer. Because it does not involve special tools, it is not professional. However, you can generally understand the quality of car sheet metal parts with them.

The function of car body is self-evident. As a place to accommodate goods and passengers, its firmness is an important indicator of its performance. To make the car body more solid, the use of high-strength steel is on the one hand, and on the other hand, depends on the quality of the sheet metal, which is mainly reflected by the connection strength.

You know several connection methods of vehicle body: resistance welding (spot welding), laser welding, riveting, gluing, plasma welding, etc. At present, resistance welding and laser welding are mainly used in automobile manufacturing industry. They are different in welding principle, so the sheet metal effect of car body is also different.

In recent years, laser welding has been talked about in the media circle, and has become the selling point of many models often mentioned by sales. The so-called laser welding is an efficient and precise welding method using a laser beam with high energy density as the heat source. The welding process belongs to the heat conduction type, that is, the laser radiation heats the surface of the workpiece. The surface heat is guided to the internal diffusion through heat transfer. By controlling the width, energy, peak power, repetition frequency and other parameters of the laser pulse, the workpiece is melted to form a specific molten pool.

However, compared with laser welding, resistance welding (known as "spot welding") appeared earlier and has a wider range of applications. Resistance welding is a method to compress the weldment between two electrodes through the electrode arm of the welding gun, apply current, and heat it to the molten or plastic state by using the resistance heat effect generated by the current flowing through the workpiece contact surface and adjacent areas, so as to form metal bonding.

How to separate the two types of welding? In fact, it is very simple. If the welding position is a smooth weld, it is laser welding, and the welding points are resistance welding. These two welding methods are used in many parts of the car body, such as the roof and the side wall.