Black Carbon Steel Flange

QS Flange: Black Flange Chinese Factory Direct

Forged carbon steel flange with a black anti-corrosion coating, ASME B16.5, 1/2 to 24 inch and 150LB to 2500LB, RF face for water, waste handling and hydrocarbon lines.

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One-Minute Overview

Forged carbon steel flange with a black paint finish for waste, water and hydrocarbon lines.
ASME B16.5 dimensions, 1/2 to 24 inch, pressure classes 150LB to 2500LB.
A raised face compresses a soft or semi-metallic gasket through 150LB to 900LB.
High classes move to a ring type joint groove and metal ring for a metal-to-metal seal.

The black flange is an ordinary forged carbon steel flange with one practical addition: a black paint layer over the finished body that keeps handling marks and surface rust off the part between the works and the site. It is made to ASME B16.5, from 1/2 to 24 inch, in classes 150LB to 2500LB, with a raised face as the standard sealing surface.

Name: Black Carbon Steel Flange
Size: 1/2"-24"
Pressure: 150LB-2500LB
Flange Face: RF
Surface: Black
Material: Carbon Steel
Process Method: Forged
Standard: ASME B16.5

Sealing follows the class. Through 150LB to 900LB the raised face presents a flat annulus that compresses a soft or semi-metallic gasket under bolt load, and the page data puts the resulting leak rate at or below 0.01%. For 1500LB to 2500LB duty the same forging is machined with a ring type joint groove and sealed by an oval or octagonal metal ring, where bolt preload drives the ring against the groove walls for a metal-to-metal joint quoted at or below 0.001%. Say which you need when you order, because the two are not interchangeable at the joint.

The black coating is a working finish, not decoration. It holds up in waste handling, water treatment and general utility service, where a bare forging would bloom with rust in storage; for acid, chloride or coastal atmosphere, ask for epoxy or galvanizing instead. Gasket choice follows temperature and fluid: graphite for steam and heat, PTFE for chemical duty, spiral wound stainless for the wide middle ground. Custom sizes and drilling are available, so bring the drawing if the line is not standard.

FAQ

Q1. Which classes come with a raised face and which need the ring joint?

Raised face covers the everyday range, roughly 150LB to 900LB, against a soft or semi-metallic gasket. From 1500LB to 2500LB the joint normally moves to a ring type joint groove with a metal ring gasket. Both are machined from the same forging to ASME B16.5, but the face is a choice at the order stage, not something to swap later.

Q2. Is the black paint doing anything, or is it just looks?

Mostly it is protection, and it earns its place in storage and in waste or water service where a bare forging rusts on the rack. It is not a coating for acid or chloride; for those, ask for epoxy or hot dip galvanizing. If the flange will be painted on site anyway, tell us and we can ship it bare.

Q3. Do I really have to tell you which gasket I plan to use?

Only if you want the joint to work first time. Graphite, PTFE and spiral wound stainless each want a different seating stress and a different bolt load, and the face finish is machined to suit. It is a two line email now against a leak, a re-torque and a shutdown later.

Q4. What is the 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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