Stainless Steel Hex Weld Nuts

When to use a hex weld nut

Use a hex weld nut when you want a permanent threaded point on a plate or section and:

You can weld, but tapping or using loose nuts is not practical.

You want to assemble from one side only (other side closed/inaccessible).

You want a strong, non-rotating nut that stays fixed to the component for life.

Typical applications:

Fabricated frames & machine bases

Automotive / body structures / chassis parts

Heavy brackets, mounting plates, guards

Anywhere a fixed stainless thread is needed on a plate or structural member.

Environment & corrosion (material selection)

For stainless systems (typical for your product line):

Indoors / general outdoor → A2 (304) hex weld nut

Marine / coastal / chloride / chemical → A4 (316) hex weld nut

Match nut with bolt:

A2 weld nut with A2 bolts

A4 weld nut with A4 bolts

If you’re using carbon steel, match coating + grade to the rest of the hardware (plain, zinc, HDG, etc.).

Weld style & base design

Hex weld nuts come in different weld configurations – choose based on base thickness, process and access:

Projection weld hex nut

Small weld projections on the nut face.

Designed for resistance/spot welding to sheet metal.

Gives repeatable welds in production lines (automotive, mass fabrication).

Plain-face hex weld nut

Flat face for manual fillet welding around the nut.

Best for thicker plates or where projection welding isn’t available.

Pilot / boss type hex weld nut

Has a small pilot/boss that fits into a punched/drilled hole.

Helps locate the nut and keep it centred.

Reduces risk of weld spatter entering threads.

Thumb rule:

Thin sheet + resistance welding → Projection hex weld nut.

Thicker plate + manual welding → Plain-face hex weld nut (with or without pilot).

Thread size, load & engagement

When choosing size:

Select M6, M8, M10, M12, etc. based on:

Required clamping load

Matching bolt size

Ensure sufficient thread engagement:

Typically aim for ≈ 1× bolt diameter engagement in steel designs (or as per your design standard).

The joint capacity depends on:

Bolt strength

Nut thread strength

Weld strength between nut and plate

If the weld is weak, it becomes the weakest link even with high-grade nuts and bolts.

Hole & fit (for pilot-type hex weld nuts)

If using pilot/boss type:

Punch/drill a hole to the correct diameter for the pilot.

The pilot:

Locates the nut during welding

Helps keep threads aligned

Acts as a barrier to weld spatter entering the thread

Wrong hole size can cause:

Poor seating or misalignment

Difficult welding

Reduced strength

Hex weld nuts follow the same property class logic as standard hex nuts (e.g., A2-70, A4-70).

The main difference is that the nut is fixed by welding, so the weld becomes part of the load path.

A2-70 Hex weld nuts

Material: A2 (304) stainless steel

Property class: 70 (for use with A2-70 bolts/studs).

Suitable for:

General stainless fabrications (frames, brackets, panels).

Indoor / outdoor structures in mild to moderate corrosive environments.

A4-70 Hex weld nuts

Material: A4 (316) stainless steel

Property class: 70 (for use with A4-70 bolts/studs).

Suitable for:

Marine, coastal, chemical, chloride-rich environments.

Stainless structures and equipment where long-term corrosion resistance is critical.

Key mechanical points:

For a given size (e.g., M10 A2-70 hex weld nut):

Thread strength is similar to a standard A2-70 hex nut.

Overall joint strength = min( bolt capacity, nut thread capacity, weld capacity, plate capacity ).

Correct weld size, length and quality are essential to fully use the bolt+nut property class.