A105 Weld Neck Flange

QS Flange: Yuyao Weld Neck Flange

ASTM A105 forged steel weld neck flange, 2 inch 300LB RF with STD wall, built to ANSI B16.5 for permanent high-stress piping connections.

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One-Minute Overview

Forged A105 carbon steel weld neck flange for 2 inch Class 300 joints.
Long tapered hub spreads weld stress into the pipe wall.
Raised face seals with spiral wound or ring joint gaskets.
ANSI B16.5 drilling keeps it interchangeable with Class 300 systems.

The A105 weld neck flange is a forged carbon steel hub flange for 2 inch lines in high pressure and high temperature service. Its long tapered neck changes section gradually, so the butt weld to the pipe sees far less stress concentration than a flat plate joint would give it. The raised face provides a defined seating band for the gasket, and the body is forged rather than cast, which leaves a tighter grain structure through the hub and the face.

Name: A105 Weld Neck Flange
Size: 2"
Pressure: 300LB
Material: A105
Wall Thickness: STD
Flange Face: RF
Standard: ANSI B16.5
Feature: Easy and Quick Installation

Forging refines the grain and closes internal voids, which is why these flanges are specified where loads cycle and temperature swings. ANSI B16.5 governs the face, bolt circle, bolt hole spacing and the rating, so the flange drops into an existing Class 300 system without modification. Fit a spiral wound or ring joint gasket to suit the service, bring the studs up in a star pattern, and watch the face gap as the load comes on.

Typical duty is refinery transfer lines, separator skids and wellhead flow lines, plus main steam lines, boiler feedwater pumps and turbine connections in power generation. In all of them the joint is meant to be permanent: once welded and bolted, the flange is expected to stay leak free through years of thermal cycling.

FAQ

Q1. Why A105 instead of a plain structural steel?

A105 is a forged carbon steel with high tensile strength and good impact resistance, and the forging step refines the grain and removes porosity. That combination matters on a 300LB joint that sees cyclic loading and thermal shock: the pressure boundary stays sound and the face does not distort as the line heats and cools.

Q2. What is the tapered hub actually doing?

It changes the section gradually from the thick flange ring down to the pipe wall. Instead of a hard step where stress piles up, the hub lets the load spread along the neck before it reaches the weld. On a 2 inch 300LB joint that is the difference between a joint that lasts and one that cracks at the toe of the weld.

Q3. Which gasket suits the raised face here?

Spiral wound or ring joint gaskets are the usual pairing, chosen for the medium and the temperature. The raised face gives the gasket a defined band to sit on, so compression stays even around the ring. Match the gasket material to the fluid, keep the face clean and undamaged, and the joint will hold at the rated class.

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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