Square Projection Weld Nuts

Structural Characteristics

Square projection weld nuts is a square nut with multiple welding projections at the bottom. Its structural design is centered around three key goals: welding reliability, precise positioning, and anti-turning performance.

【1】Square base

（1）Shape: A perfect square with all four sides of equal length and all four corners at right angles. It can automatically prevent rotation when it fits into the square hole of the workpiece.

（2）Edge width: For example, M8 is 14mm, M10 is 17mm. It provides sufficient pressure-bearing area to prevent the nuts from getting stuck in the base material during welding.

（3）Thickness (height): Usually 6 to 10mm. It ensures sufficient thread engagement length to provide connection strength.

【2】Welding projections

（1）Quantity: Distributed in a four-point symmetrical manner to ensure uniform current and balanced weld core

（2）Position: At the four corners of the bottom surface, close to the edge, to enhance welding stability

（3）Shape: Spherical or conical-topped shape, with a smooth top

（4）Height: 0.5 ~ 1.2 mm, to ensure close contact with the base material

Width/Diameter: Approximately 1.5 ~ 2.5 mm

【3】Internal thread

（1）Thread specification: Metric M4 to M16, Imperial #6 to 5/8″. Forms a detachable connection with the matching bolts.

（2）Thread accuracy: 6H (metric), 2B (imperial). Ensures a good fit between the Square projection weld nuts and the bolt.

（3）Thread length: Provides sufficient thread engagement length.

（4）Thread orientation: The entry end can have chamfers for easy bolt insertion.

Frequently Asked Questions

（1）What welding method is the Square projection weld nuts suitable for? What are the parameters?

The most commonly used method is Resistance Projection Welding. Take the welding of an M8 low-carbon steel nut onto a 1.5mm low-carbon steel plate as an example. The reference parameters are: current 8–11 kA, electrode pressure 2.5–4.0 kN, welding frequency 8–15 cycles (approximately 0.16–0.3 seconds).

（2）What standards do your Square projection weld nuts comply with?

We strictly follow DIN 928 (the German standard, the most widely used worldwide), ASME B18.1 (the American standard) and GB/T 13681.2 (the Chinese national standard).

（3）How to ensure the welding performance of the nuts?

The core of the welding performance is that the carbon content should be ≤ 0.25%. We conduct spectral analysis on each batch of raw materials to ensure the chemical composition is qualified. At the same time, the height and shape of the protrusions are strictly controlled within the tolerance range.