Did you know? 60° / 55°

NPT and BSPT have different flank angles, 60 against 55 degrees. They will screw together for a few turns and still not seal reliably.

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Bulkhead and weld fittings

Straight weld-on unions

Straight weld-on unions form the transition from a cutting ring joint to a welded component. The stud is welded into a tank wall, a block or a pipe end, while the tube follows through union nut plus cutting ring. This group holds 94 items.

Choice follows the tube size from 6 L (M12x1,5) up to 42 L (M52x2) in the light series, from 6 S (M14x1,5) up to 38 S (M52x2) in the heavy series, then the material, phosphated steel or stainless steel 1.4571, plus the supply form, complete or without nut as well as ring.

94 items
1 manufacturer
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Buying guide

How to choose Straight weld-on unions

What matters when choosing: properties, comparison and typical applications.

Technical data

⚡Tube 6 L to 42 L - light series for thin walled tube, heavy series from 6 S (M14x1,5) up to 38 S (M52x2) for higher loaded runs.

⚡Two series - the heavy S series accepts larger wall thicknesses, the light L series covers the standard range.

⚡Materials - phosphated steel as corrosion protection indoors, stainless steel 1.4571 for aggressive surroundings.

⚡NC clamping ring 1.4571 - versions carrying a pre-assembled NC clamping ring in 1.4571 deform the tube more gently than a classic cutting ring.

⚡Supply form - complete, or as a plain stud without nut plus cutting ring when those parts already sit on the tube.

Applications

Weld-on unions suit any point where a line ends permanently at a component: hydraulic tanks, welded frames, pipe bends, manifold blocks lacking a prepared thread. After welding the tube joint itself stays detachable, so the line can be removed for service. The 1.4571 version is chosen when stud plus tube should share the same material.