The key difference of a slotted flange (open‑slot flange) compared to a conventional flange is that its bolt holes are not closed circular holes but U‑shape or C‑shape slots opening to the outer edge of the flange. When in use, bolts are pre‑installed into the mating flange or equipment nozzle without being fully removed. To install or remove this slotted flange, simply loosen the bolts a few turns, then slide the flange radially in/out over the bolt shanks. This design eliminates the need to fully withdraw long bolts in confined spaces, making it ideal for flanged connections that require frequent opening – such as filters, manways, heat exchanger channel ends, and reactor charge ports.
The sealing performance of a slotted flange is equivalent to that of a traditional solid‑hole flange because the gasket compression force is provided by bolt torque, and the slot does not alter the pressure distribution on the sealing face. We can apply corner rounding or post‑weld heat treatment to the slot edges to avoid stress concentration. Manufacturing generally references ASME B16.5 or EN 1092‑1, with slot dimensions fully customizable per drawing.
Why Choose Us / Advantage
Warranty – 12‑month quality warranty; each flange comes with dimensional inspection report and material certificate (EN 10204 3.1).
Customization – Slot length, width, and opening orientation machined per customer drawing; non‑standard indexing or threaded slots available.
Fast delivery – Forged blanks for common carbon/stainless steel slotted flanges in stock; machining in 10‑15 days; full custom orders 20‑25 days.
Rigorous testing – 100% magnetic particle (MT) or liquid penetrant (PT) inspection on slot areas to ensure no cracks; batch PMI and hardness testing performed.
Error‑proof packaging – Each flange individually wrapped with slot orientation marked; multi‑layer plywood cases for sea freight and international courier.
Technical Data
★ Standard: ANSI/ASME B16.5, GB/T 9119, DIN 2573
★ Body Material: Carbon Steel (A105, Q235, 20#); Stainless Steel (304, 316, 304L, 316L)
★ Pressure Class: Class 150, 300, 600 (PN10~PN100)
★ Size Range: DN15 ~ DN2000 (1/2" ~ 80")
★ Face Type: Raised Face (RF), Flat Face (FF)
★ Surface Treatment: Anti-rust oil (carbon steel) / Pickling & passivation (stainless steel)
Applications
● Food & pharmaceutical sanitary lines – Daily CIP cleaning, flanges require frequent opening
● Wastewater treatment plants – Pump suction/discharge, strainer access covers (wet and confined)
● Chemical reactor manways – Open for inspection without full bolt removal
● Shipboard piping systems – Flange connections through bulkheads or tight compartments
● Heat exchanger channel ends – Quick opening for tube bundle cleaning
● Test rigs and temporary piping – Fast reconfiguration, saves labor hours
