What Is A Projection Welding Nut, And What Advantages Does It Have Over A Welding Nut?

Projection welding is a high-efficiency welding method that can perform multi-point welding simultaneously, which can be used to replace arc welding, brazing and riveting. This method has the remarkable characteristics of fast processing speed and no other consumption except electricity. This article mainly shares the advantages and related characteristics of projection welding nuts compared with ordinary welding nuts.

I. What is a Projection Welding Nut?

Projection welding nuts are mainly used for welding stamping parts of low-carbon steel and low-alloy steel. There are many types of projection welding. In addition to sheet projection welding, there are also projection welding of bolts, screws and other parts, cross wire projection welding, pipe projection welding and sheet T-type projection welding.

II. Advantages and Disadvantages of Projection Welding Nuts

(I) Advantages of Projection Welding Nuts

1. Multiple welding points can be welded simultaneously within one welding cycle of the welding machine; the number of welding points that can be welded at one time depends on the uniform electrode force and welding current that the welding machine can apply to each projection.

2. Since the welding current is concentrated on the projections and there is no shunt problem through adjacent welding points, a smaller overlap and smaller point spacing can be adopted.

3. The position of projection welding points is more accurate than that of spot welding points, and due to the uniform size of the projections, the quality of projection welding points is more stable. Therefore, the size of projection welding points can be smaller than that of spot welding points.

4. Since the projections can be set on one part, the welding marks on the exposed surface of the other part can be minimized.

5. Projection welding adopts large flat electrodes, whose heating and wear degree is much smaller than that of spot welding electrodes, which prolongs the service life of the electrodes, thereby saving the time for electrode trimming and replacement and reducing the electrode maintenance cost.

6. Since multiple points can be welded simultaneously with small projections, welded components with small deformation can be obtained.

7. Projection welding can effectively overcome nugget deviation, so it can weld parts with a thickness ratio of up to 6:1.

(II) Disadvantages of Projection Welding Nuts

1. Sometimes, additional processes are required to prefabricate one or more projections.

2. When welding several welding points simultaneously with the same electrode, the alignment accuracy of the workpiece and the size of the projections (especially the height) must maintain high-precision tolerances to ensure uniform electrode force and welding current, so as to ensure the uniform quality of each welding point.

3. When welding multiple welding points simultaneously, a high-power welding machine with high electrode pressure and high mechanical precision is required, and its pressure mechanism must have high follow-up performance.

III. Characteristics, Advantages and Disadvantages of Welding Nuts

A welding nut is a nut suitable for welding outside the nut. It is usually made of weldable materials and has a relatively large thickness, which is suitable for welding operations. Welding is equivalent to fusing two separate parts into a whole: the metal is melted by high temperature, mixed, and then cooled to complete the connection. Alloys can be added in the middle, and the internal connection relies on molecular force, whose strength is generally higher than that of the parent metal.

The debugging of welding parameters needs to be carried out according to the size of weld fusion, and welding defects are eliminated by adjusting welding parameters. The quality of welding is closely related to pre-welding treatment, and impurities such as dust and oil stains on the surface of the workpiece need to be cleaned.

(I) Advantages: The welding connection has high strength and a wide range of applications, and can be used for connecting workpieces of different thicknesses.

(II) Disadvantages: The high temperature during welding will cause deformation of the connected parts, and the connection cannot be disassembled after welding; some active metals (such as aluminum, magnesium, etc.) cannot be welded by conventional methods, requiring protectors or argon arc welding, which has high requirements on processing technology and precision.

IV. Additional Advantages of Projection Welding Nuts Over Welding Nuts

In addition to the above-mentioned advantages of projection welding nuts themselves, compared with welding nuts, projection welding nuts also have the following advantages:

1. Multiple welding points can be welded simultaneously within one welding cycle, which not only has high production efficiency but also no shunt influence. Therefore, welding points can be arranged in narrow parts without being limited by point spacing.

2. The current density is concentrated on the projections, and the current density is high, so welding can be performed with a smaller current, and small nuggets can be reliably formed; while in spot welding, it is difficult to form a nugget smaller than a certain size corresponding to a certain plate thickness.

3. The projections have accurate positions and consistent sizes, and the strength of each welding point is uniform. Therefore, for a given strength requirement, the size of the projection welding point can be smaller than that of the spot welding point.

4. Large flat electrodes are adopted, and the projections are set on one workpiece, which can minimize the indentation on the exposed surface of the other workpiece; at the same time, the large flat electrodes have small current density and good heat dissipation, and the electrode wear is much less than that of spot welding electrodes, which greatly reduces the maintenance and repair costs of the electrodes.

5. Compared with spot welding, the influence of oil stains, rust, oxide scale, coatings and other coatings on the workpiece surface on projection welding is smaller, but a clean and tidy workpiece surface can still obtain more stable welding quality.

In summary, projection welding is widely used due to the above-mentioned many advantages. Its shortcomings are that additional processes for stamping projections are required, the electrode structure is relatively complex, and due to the need to weld multiple welding points simultaneously, a high-power welding machine with high electrode pressure and high mechanical precision is required.