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You’ve got a system where threaded joints keep failing under thermal cycling or vibration—the real headache is that standard fittings loosen or gall over time, and that’s where the butt weld union design steps in to solve it by fusing the pipe to the fitting at the weld neck while keeping a separable threaded connection for maintenance access, which basically eliminates the leak path that plagues plain threaded joints in steam or hydraulic lines.
What it does is handle the pressure swing form 150# to 2500# without creeping open, and the 304 or 316 stainless body—we usually stock 316L for chloride-heavy environments—holds up to -20°C to 400°C, though if you’re pushing past 350°C for extended runs, you’ll want to check the gasket material because the standard PTFE seal starts to soften there.
The thread options are NPT, BSPT, or BSPP, and our company can match your existing setup, but most buyers go with NPT for taper-to-taper sealing, and the size range runs from 1/2" up to 12" nominal bore (DN15 to DN300), with surface finishes like polished or sandblasted depending on whether you need cleanability for food-grade lines or just corrosion resistance for a chemical skid.
Lead time is usually 20 days or so for a standard run of 50 pieces (that’s the MOQ), but custom OEM orders—say you need a specific alloy like duplex or a non-standard thread depth—might stretch to 30 days, and we’ll include a COA with HPLC-grade traceability on the materail cert if you request it, though we don’t always list the ppm sulfur content unless you ask.
The fittings meet ASME B16.11 and MSS SP-83, but they’re not suited for vacuum service below 10^-3 torr without a custom seal face, and that’s a limitation we’re upfront about because the standard O-ring isn’t that pull.
Anyway, we’ve been making these for chemcial transfer and high-pressure steam loops, and one thing a buyer might not think to ask is that internal weld bead can leave a slight ridge on sizes under 2"—if you’re running pigging systems, we can bore it out at the factory for a smoother ID.
Our standard MOQ is 50 pieces, but we do accept custom orders with mixed thread types like NPT and BSPT. Just let us know the specs, and we'll handle it.
For 500 pieces, lead time runs around 20-25 days typically. It depends on the size and finish, but we'll confirm once we get the order details.
Yes, we can provide PED certification and material test reports for 316 stainless steel. Just request them when placing the order, and we'll include the docs.
Yes, carbon steel works fine up to 400°C, so 350°C steam lines are no problem. Make sure you specify the pressure rating, as that affects the joint design.
We typically pack polished unions in wooden cases or pallets with foam inserts to protect the surface finish. For export, we can also add cartons if you prefer.
