Hexagon Deep Collar Projection Weld Nuts

The three welding protrusions at the bottom of the Hexagon Deep Collar Projection Weld Nuts are the key structural features that distinguish them from ordinary nuts. These three points are evenly distributed at 120° and play the following four core roles during the resistance spot welding process:

（1）Current is concentrated, and it melts first.

The cross-sectional area of the protruding point is smaller than that of the nut base. When the welding current passes through, the current density sharply increases at the protruding point, generating intense resistance heat, causing the protruding point to melt preferentially before the nut body and the base metal.

（2）Three points determine a plane, with adaptive unevenness

Three points determine a plane. Even if there is slight unevenness on the base material surface (such as oil stains, minor bumps and depressions), or if the bottom surface of the Hexagon Deep Collar Projection Weld Nuts is not absolutely flat, the three protruding points can ensure that at least three points are in stable contact with the base material. This significantly reduces the sensitivity of the welding process to the surface quality of the workpiece, and improves the welding success rate.

（3）Form three symmetrical weld cores, with uniform welding strength

The three protrusions melt simultaneously upon power application, and under the pressure, three evenly distributed weld cores are formed. Compared with single-point or two-point welding, the three-point structure results in a more uniform distribution of welding strength, and stronger resistance to torsion and pull-out.

（4） Limiting molten metal and reducing spatter

The protrusion design confines the molten metal to the local area where the protrusion is located. Under the action of electrode pressure, the molten metal spreads outwards to a limited extent, making it less likely to be squeezed out and form spatter.

Daily inspection

The Hexagon Deep Collar Projection Weld Nuts is permanently fixed to the workpiece through resistance spot welding. Under normal usage conditions, it requires almost no daily maintenance. However, in long-term service or specific environments, appropriate inspections and maintenance can extend its service life and ensure the reliability of the connection.

（1）Welding point appearance

Observe visually or using a magnifying glass, there should be no cracks, no rust, and no signs of weld detachment. If cracks or weld detachment are found, the weld needs to be re-welded or the nut needs to be replaced.

（2）Flange/Base Fit

Visual inspection to check if the flange surface is tightly attached to the workpiece without any warping. Warping may indicate poor welding and the strength should be evaluated.

（3）Thread Condition

Using a gauge or visual inspection, if the thread is intact without any slippage or iron filings blocking, no modification is needed. If there is a slight blockage, a reaming with a tap can be used; if there is slippage, the Hexagon Deep Collar Projection Weld Nuts needs to be replaced.

（4）Anti-rust Layer

Visual inspection to ensure the coating or finish is complete without large areas of rust. Local rust can be remedied by applying anti-rust paint or cold galvanizing spray.