DIN W.Nr.1.4306 WN Flange

QS Flange: Yancheng DIN W.Nr.1.4306 WN Flange

Forged weld neck flange in SS304L (DIN W.Nr.1.4306), 4 inch Class 300LB with raised face, for welded high-temperature and high-pressure piping.

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One-Minute Overview

Forged weld neck flange in SS304L, the 1.4306 low-carbon grade, 4 inch and Class 300LB.
Tapered hub follows the pipe bore, keeping flow smooth and erosion low inside the joint.
Low carbon holds chromium carbides back at grain boundaries, so welds keep their corrosion resistance.
Raised face concentrates gasket load for a tight seal in hot, high-pressure service.

The DIN W.Nr.1.4306 weld neck flange is forged from SS304L, the low-carbon member of the 304 stainless family, and it carries a 4 inch line into a valve, vessel or header. The raised face sets the gasket compression, and the tapered hub follows the pipe bore so the two openings line up. Because the carbon level sits below standard 304, the weld zone keeps its corrosion resistance after fabrication.

Name: DIN W.Nr.1.4306 WN Flange
Size: 4 Inch
Pressure: 300LB
Material: SS304L (W.Nr.1.4306)
Type: WN
Flange Face: RF
Process Method: Forged
Feature: Strong Stiffness, Good Sealing
Usage: High Temperature, High Pressure and High Sealing Requirements
Standard: DIN (material W.Nr.1.4306)

The tapered hub hands the pipe wall thickness over to the flange body in a smooth transition, so the weld sits away from the sharp corner where stress would otherwise collect. The bore runs flush with the pipe, which keeps flow unrestricted, holds turbulence down and limits erosion at the joint — worth having on transfer lines that run hot and under pressure. In SS304L the alloy resists water, weak organic and weak inorganic acids, and holds up down to roughly pH 4.5 in low-chloride aggressive media.

Fit the hub bore to the pipe inside diameter first, then set the gasket for the raised face and the class. Bolt with studs of the matching class, tighten in a star pattern in stages, and confirm the mating flange carries a compatible face. Service covers refinery and petrochemical piping, process equipment connections and high-temperature transfer lines, plus chemical plants handling corrosive media, where the forged body and the low-carbon weld zone are what keep the joint sound over time.

FAQ

Q1. Why specify 1.4306 low-carbon steel instead of plain 304?

The 1.4306 grade is SS304L, with carbon held below the standard 304 level. That headroom stops chromium carbides from precipitating at the grain boundaries during welding, so the heat-affected zone keeps its corrosion resistance. On a weld neck flange, where the hub is welded straight into the line, that is often the difference between a joint that lasts and one that fails at the weld.

Q2. Does the weld neck shape really matter on a 4 inch line?

It does. The tapered hub hands the pipe wall thickness to the flange body gradually, so the weld sits clear of the corner where stress would pile up. The bore also stays flush with the pipe, so there is no step for the flow to trip over — less turbulence, less erosion, and a joint that behaves through pressure cycling.

Q3. pH 4.5 — so what can I actually run through it?

Water, weak organic acids, weak inorganic acids, and low-chloride media down to about pH 4.5. Picture refinery transfer lines and general chemical service rather than hot concentrated acid. If your medium sits outside that envelope, send us the chemistry before the order goes in; material selection deserves a conversation, not a guess.

Q4. What is the smallest order I can place?

Standard flange insulation gasket kits start at one set, and standard gaskets, studs, washers and sleeves start at one piece. Parts made to your drawing or to a non-standard bolt pattern are quoted one by one, because the minimum really depends on the material and the tooling involved.

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