Q235 BL Blind Flange

QS Flange: Yancheng BL Flange

Q235 forged steel blind flange, 1-1/2 inch Class 150LB raised face per ASME B16.5, serrated face and black anti-rust coating for low-pressure isolation.

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One-Minute Overview

Hot-forged Q235 carbon steel disk that blanks a 1-1/2 inch Class 150LB joint.
Raised face serrated to bite into spiral wound or non-asbestos gaskets.
Bore, bolt circle and thickness machined on CNC lathes to ASME B16.5.
Black anti-rust coating covers storage, transport and humid service conditions.

This BL flange is a blind flange in Q235 mild carbon steel: a solid plate with no bore, hot forged and machined to ASME B16.5 for a 1-1/2 inch Class 150LB joint. It closes dead-end lines, future tie-ins, test ports, vessel manholes and drain nozzles, and it carries a black anti-rust coating for the trip to site.

Name: BL Flange
Size: 1-1/2 Inch
Class: 150LB
Material: Q235
Flange Face: Raised Face
Standard: ASME B16.5
Process: Forged Steel Flange
Coating: Black Anti-rust Coating
Feature: Strong Stiffness, Good Sealing
Usage: Pipeline Fittings, Industry, Pressure Vessels, Water Conservancy, Electricity, Power Stations

Q235 is a mild carbon structural steel chosen for good weldability and formability, which puts this flange in low-pressure piping, tank nozzles and general industrial duty rather than corrosive or hot service. The billet is hot forged, a step that refines the grain structure, closes internal voids and builds the directional strength that keeps the disk flat when the bolts are pulled up. Controlled cooling after forging holds that structure, and the piece is then machined on CNC lathes so the bore, bolt circle and thickness land inside the ASME B16.5 tolerances.

The raised face is finished with a concentric serration in the 125-250 µinch roughness range. That tooth pattern bites into spiral wound and non-asbestos gaskets at first tightening and keeps the joint sealed when line temperature moves. Rated 150LB, roughly 285 psi at ambient temperature under ASME B16.5, the flange covers blanking off dead-end lines, future tie-ins, test ports, manhole covers, inspection openings and drain nozzles.

Every piece leaves with the black anti-rust coating, an oil-based temporary preventive that protects the machined surfaces for six to twelve months of indoor or outdoor storage before installation. Where a project needs longer preservation, a solvent-removable clear film can be applied on request. Handle the flange by the rim, keep the serrated face off the ground, and leave the coating in place until the joint is made up.

FAQ

Q1. What makes Q235 suitable here, and where would it not be?

Q235 is mild carbon steel with good weldability and formability, so it suits low-pressure piping, tank nozzles and general industrial closure where the medium is not aggressive. For corrosive or high-temperature duty you would want another grade, and the same pattern can be quoted in one.

Q2. Does the serrated face really matter?

It does, more than people expect. The concentric serration gives the gasket something to bite into, so the joint seals at first tightening and stays sealed when temperature moves. A smooth face works too, but it needs more bolt load for the same result, and on a 150LB joint you would rather not lean on bolt load alone.

Q3. How long can it sit in the yard before installation?

The black anti-rust coating is an oil-based temporary preventive rated for six to twelve months of indoor or outdoor storage. Keep the flange off the ground, face up on timber, clear of standing water. If the project slips past that window, wipe the face, inspect for rust and touch up before bolting up.

Q4. What is your minimum order quantity?

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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