Hex Flange Welding Nuts

Welding process

The core welding process of the Hex flange welding nuts is resistance spot welding. It is an efficient and reliable connection method. The working principle is ingenious: The flange surface of the nut is equipped with carefully designed protrusions. When the welding current passes through, these protrusions become the areas with the highest concentration of resistance. Under the immense pressure, they rapidly melt, thereby forming a strong weld core. The working process can be divided into four steps:

（1）Positioning and Pressurization

The automatic feeding system precisely positions the Hex flange welding nuts on the base material. The upper and lower electrodes apply the preset pressure, ensuring a tight fit between the nut and the sheet metal.

（2）Electric heating

A current of several thousand amperes passed through the protrusions in an instant, causing the area beneath them to rapidly melt.

（3）Pressure retention and crystallization

After the current is cut off, the electrode pressure continues to be maintained, allowing the molten metal to cool and crystallize under pressure, forming a dense weld core.

（4）Reset and Completion

The electrode is lifted, and one welding cycle is completed. The welded nut is integrated with the sheet metal, and its thread strength is usually higher than that of the base material itself.

Key process parameters

In order to achieve the most ideal welding quality for the Hex flange welding nuts, precise control over the following three key parameters is of vital importance:

（1）Welding current

This is the primary factor affecting the welding strength. If the current is too low, it will result in incomplete welding; if it is too high, it may cause spatter or even "burn-through" of the Hex flange welding nuts.

（2）Electrode pressure

It is necessary to provide sufficient pressure to ensure that the workpiece is tightly in contact, but excessive pressure may prematurely crush the protrusions, thereby weakening the welding effect.

（3）Welding time

It is usually very short (a few tens of milliseconds) and is used to control the heat input, preventing the nut from overheating.

Take the welding of a 1.5mm low-carbon steel plate with a common M8 Hex flange welding nuts as an example. The reference parameters are:

Electrode pressure: 2.5 - 4.0 kN

Welding current: 8 - 11 kA

Welding time: 8 - 15 cycles (approximately 0.16 - 0.3 seconds)