Groove and Tongue Flanges Manufacturer in India

A Tongue and Groove (T&G) flange is a matched pair of flanges — one has a raised ring (the tongue) and the mating flange has a matching machined depression (the groove). When bolted together, the tongue locates into the groove and fully confines the gasket inside the groove cavity. This prevents gasket blow-out, self-centres the joint, and gives superior leak integrity compared with a raised-face (RF) connection.

Per ASME B16.5 both types use the same principle but differ in the radial width of the tongue/groove ring. Large T&G has wider tongue and groove dimensions, giving a bigger gasket seating area — used for standard process-piping flanges. Small T&G has a narrower ring width — typically used for vessel nozzle covers, pump covers, and compact joint designs where a smaller face is acceptable.

No. Tongue and groove flanges are a matched pair — a tongue flange must always mate with a groove flange of the same NPS, pressure class, and T&G type (large or small). A tongue flange bolted to a raised-face (RF) flange would have the tongue bearing on the RF face instead of seating the gasket, creating uneven bolt load and almost certain leakage.

Gaskets are sized to fit inside the groove — the gasket OD matches the groove OD and the ID matches the groove ID. Common types: spiral-wound gaskets (inner ring only — no centring ring needed, as the groove self-centres), solid metal ring gaskets, and soft ring gaskets (PTFE, CAF, graphite). Because the gasket is confined on all four sides, much higher seating stress is achieved, allowing harder gasket materials.

Per ASME B16.5 the tongue height (equal to the groove depth) is 1.65 mm (1/16") for Class 150 and 300 — the same as the raised-face height. For Class 400, 600, 900, 1500, and 2500 the tongue height is 6.35 mm (1/4"). This height is included in the minimum flange thickness for Class 150/300 but is additional to the minimum thickness for the higher classes.

Both are paired face types with a projection on one flange and a recess on the other. The difference is the gasket bearing area: in Tongue and Groove (T&G) the gasket contacts the bottom of the groove only (fully confined). In Male and Female (M&F) the male face is flat and raised and the female face is a recess — the gasket sits on the male face inside the female recess. T&G gives slightly better gasket confinement; M&F is more common for pipe flanges, while T&G is more common for nozzle and heat-exchanger connections.

Carbon steel T&G flanges are forged to ASTM A105 (standard service) or ASTM A350 LF2 (low temperature to −46°C / −50°F), with the face machined to ASME B16.5 T&G dimensions. Alloy steel uses ASTM A182 (F5, F9, F11, F22, F91); stainless steel uses ASTM A182 (F304/304L, F316/316L, F321, F347, F904L). All supplied with EN 10204 3.1 material test certificates.

Specify T&G over raised-face (RF) flanges when: (1) the fluid is highly hazardous or toxic and gasket blow-out must be prevented; (2) very high differential pressure across the face requires confined gasket seating; (3) high fluid velocity could erode or wash out an exposed gasket; (4) the joint is on a heat-exchanger channel cover or pump casing needing reliable re-assembly after maintenance; or (5) the process/company specification mandates a confined-gasket face for the service category.

Yes. Tesco Steel supplies T&G flanges in Duplex 2205 (ASTM A182 F51, UNS S31803/S32205), Super Duplex 2507 (F53, UNS S32750), and Zeron 100 (F55, UNS S32760). These are commonly specified for offshore oil & gas heat-exchanger nozzles, seawater cooling systems, and desalination-plant connections where both high strength and chloride-corrosion resistance are needed.

Per ASME B16.5 the gasket-seating contact face is finished to 125–250 AARH (3.2–6.3 µm Ra) serrated for most gasket types; spiral-wound or sheet gaskets use 125–250 AARH concentric or phonographic serrations. For solid metal ring gaskets a smoother 63–125 AARH (1.6–3.2 µm Ra) is required on the groove floor. Tongue-height and groove-depth tolerances are held to ±0.38 mm (±0.015") per ASME B16.5.