Hebei Yuanjida Group
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blind flange

Blind flange is also called blank flange. Hebei Yuan Jida is blind flange manufacturer or blind flange supplier. Pipe blind flange like a flange cover, also called blind disk or flanged pipe plug.It has no holes in the centre, for to seal the pipe opening. So it's function is the same as the pipe plug or the pipe cap. The difference is blind flange is a detachable equipment, easy to replace or do maintenance. We produce a105 blind flange as blank flanges suppliers. If you are looking for blind flange in China or blind flange factory, you could contact with me, we are professionl blind flange company. and we are known as spectacle blind flange manufacturers.

Major Function - Where to use

The blind flange or blank flange is used to close ends of piping systems. It is a kind of round plate with no center hold but with all the proper bolt holes. This blind flange is available in various sizes and materials and is used to provide positive closer on the ends of pipes, valves or equipment nozzles. This flange helps in easy access to a line once it has been sealed. The blind flange is sometimes custom made or machined to accept a nominal sized pipe to which reduction is being made.

A blind flange is useful for making repairs to a pipeline further up the line. In fact, during construction of a pipeline, a blind flange may be built into the final length of pipe. This allows for expansion or continuation of the pipeline simply by adding onto the final flange.

Manufacturing Types and Costs

Generally has four types: Forging, casting and forging, medium plate cutting, casting, the price of forging products is the highest, the middle plate is the second, casting and forging is the lowest and casting is the worst process when compared with others.

The best quality is forging and medium plate, casting and forging is a bit worse.

Casting Blind Flange

The shape of the the casting flange blank is accurate, has the small processing capacity, the cost is low, but there are casting defects (air hole crack inclusions); And the streamline of the internal casting part is bad (if it is a cutting part, the streamline is worse).

Forging Blind Flange

Forged blind flange generally have lower carbon content than cast flanges and are not easily to rust. Forgings have better streamlined shape, denser structure and better mechanical properties than cast flanges;

If the forging process is improper, the grain will be large or uneven, and the hardening crack will occur. The forging cost is higher than the casting flange.

Forgings can withstand higher shear and tensile forces than castings.

What do blind flanges do?

Without a blind flange, it would be next to impossible to repair or perform ongoing maintenance to a pipeline unless the flow was shut off at a earlier valve, which could affect miles of pipeline.

The use of flanged pipe has significantly sped up the process for constructing pipelines. It has also made the task of repair and sectional replacement easier. Sections of pipe can now be assembled anywhere in the world and shipped to the job site. Once there, they can simply be bolted in place and the repair is done.

Piping is easier to drill or weld at the construction stage. Once it was in use,drilling or welding will need prolong cleaning especially when the fluid transferred is combustible. For the mean of future extension, either the blind or valve would be used to seal the end.

Advantage of blind flanges (blind flange manufacturer)

  • A much more cost efficient way to seal a pipe when doing repairs.
  • Blind flanges are convenient to install.
  • They can save a good amount of time and money.

Features of blind flanges(blind flange supplier)

Some important features of blind flanges are as follows:

  • Blind flanges are sometimes supplied with NPT fittings which allow pressure test connections to be fitted.
  • They are used to blank off the ends of pipe.
  • They are also used to blank off the ends of valves and pressure vessel opening.
  • Considering factors like internal pressure and bolt loading, blind flanges, especially in the larger sizes, are the most highly stressed of all types of flanges.
  • Since the maximum stresses in a blind flange are bending stresses at the center, they can safely be allowed to be higher than in other types of flanges.
  • Blind flanges are made to fit standard pipes in all sizes.

Materials

Pipe blind flanges are manufactured in all the different materials like stainless steel, cast iron, aluminium, brass, bronze, plastic etc. but the most used material is forged carbon steel and have machined surfaces(raised face blind flange).

Flanges are welded to pipe and equipment nozzle. Accordingly, it is manufactured from the following materials;

  • Carbon steel
  • Low alloy steel
  • Stainless steel
  • Combination of Exotic materials (Stub) and other backing materials

The list of materials used in manufacturing is covered in ASME B16.5 & B16.47.

  • ASME B16.5 -Pipe Flanges and Flanged Fittings NPS ½” to 24”
  • ASME B16.47 -Large Diameter Steel Flanges NPS 26” to 60”

Commonly used Forged material grads are

  • Carbon Steel: – ASTM A105, ASTM A350 LF1/2, ASTM A181,a105 blind flange
  • Alloy Steel: – ASTM A182F1 /F2 /F5 /F7 /F9 /F11 /F12 /F22 blind flange
  • Stainless Steel: – ASTM A182F6 /F304 /F304L /F316 /F316L/ F321/F347/F348 blank flange

Frequently used astm grades(blank flanges suppliers)

Material Fittings Flanges Valves Bolts & Nuts
Carbon Steel A234 Gr WPA A105 A216 Gr WCB A193 Gr B7
A194 Gr 2H
A234 Gr WPB A105 A216 Gr WCB
A234 Gr WPC A105 A216 Gr WCB
Carbon Steel
Alloy
High-Temp
A234 Gr WP1 A182 Gr F1 A217 Gr WC1 A193 Gr B7
A194 Gr 2H
A234 Gr WP11 A182 Gr F11 A217 Gr WC6
A234 Gr WP12 A182 Gr F12 A217 Gr WC6
A234 Gr WP22 A182 Gr F22 A217 Gr WC9
A234 Gr WP5 A182 Gr F5 A217 Gr C5
A234 Gr WP9 A182 Gr F9 A217 Gr C12
Carbon Steel
Alloy Low-Temp
A420 Gr WPL6 A350 Gr LF2 A352 Gr LCB A320 Gr L7
A194 Gr 7
A420 Gr WPL3 A350 Gr LF3 A352 Gr LC3
Austenitic Stainless Steel A403 Gr WP304 A182 Gr F304 A182 Gr F304 A193 Gr B8
A194 Gr 8
A403 Gr WP316 A182 Gr F316 A182 Gr F316
A403 Gr WP321 A182 Gr F321 A182 Gr F321
A403 Gr WP347 A182 Gr F347 A182 Gr F347

ASTM standards define the specific manufacturing process of the material and determine the exact chemical composition of pipes, fittings and flanges, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., and are indicated by "Grade".

The usual materials of flanges include stainless steel, carbon steel, aluminum and plastic. The choice of the material largely depends on the purpose of the flange. For example, stainless steel is more durable and is necessary for heavy use. On the other hand, plastic is more feasible for use in the home because of its reasonable price and easy installation. The materials used for flanges are under the designation of the American Society of Mechanical Engineers.

Flange materials acc. to ASTM (blind flange china)

The most common materials for pipe flanges (forged grades) are: ASTM A105 (carbon steel high temperature to match A53/A106/API 5L pipes), A350 Grades LF1/2/3 (carbon steel low temperature to match A333 pipes), A694 Grades F42 to F80 (high yield carbon steel to match API 5L pipe grades), ASTM A182 Grades F5 to F91 (alloy steel flanges to match A335 pipes), A182 Grade F304/316 (stainless steel flanges to match A312 SS pipes), A182 Gr. F44/F51/F53/F55 (duplex and super duplex to match A790/A928 pipes) and various nickel alloy grades (Inconel, Incoloy, Hastelloy, Monel).

The material qualities for these flanges are defined in the ASTM standards.

What are ASTM Grades?

For example, a carbon steel pipe can be identified with Grade A or B, a stainless-steel pipe with Grade TP304 or Grade TP321, a carbon steel fitting with Grade WPB etc.


Standard(blind flange factory)

Pipe blind Flange Standards mainly include three systems in the world, ANSI/ASME flange system(American), DIN flange system(European system), JIS flange system, other system made according to this three systems, like GB flange standard, which mainly made according to ANSI/ASME and DIN flange standard, Duwa Piping supplies those with top quality and soonest delivery time.And has the raised face blind flange.

ASME standards (blind flange company)

  • ASME B16.1 – Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250
  • ASME B16.5 – Pipe Flanges and Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard
  • ASME B16.20 – Ring Joint Gaskets and Grooves for Steel Pipe Flanges
  • ASME B16.21 – Nonmetallic Flat Gaskets for Pipe Flanges
  • ASME B16.24 – Cast Copper Alloy Pipe Flanges and Flanged Fittings: Classes 150, 300, 600, 900, 1500, and 2500
  • ASME B16.34 – Large Diameter Steel Flanges (NPS 26 through NPS 60)
  • ASME B16.36 – Orifice Flanges
  • ASME B16.42 – Ductile Iron Pipe Flanges and Flanged Fittings: Classes 150 and 300
  • ASME B16.47 – Large Diameter Steel Flanges (NPS 26 Through NPS 60)

ASTM standards

  • ASTM A105 – Specification for Carbon Steel Forgings for Piping Applications
  • ASTM A182 – Specification for Forged or Rolled Alloy Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High Temperature Service
  • ASTM A193 – Specification for Alloy Steel and Stainless Steel Bolting Materials for High Temperature Service
  • ASTM A194 – Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service
  • ASTM A694 – Specification for Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and Parts for High-Pressure Transmission Service
  • ASTM A707 – Specification for Flanges, Forged, Carbon and Allow Steel for Low Temperature Service

AWWA standards

  • AWWA C115 – Standard for Flanged Ductile Iron Pipe with Ductile-Iron or Gray-Iron Threaded Flanges

ISO standards

  • ISO 5251 – Stainless steel butt-welding fittings

MSS standards

  • MSS SP-6 – Standard Finishes for Contact Faces Pipe Flanges and Connecting End Flanges of Valves and Fittings
  • MSS SP-9 – Spot Facing for Bronze, Iron and Steel Flanges
  • MSS SP-25 – Standard Marking Systems for Valves, Fittings, Flanges, and Unions
  • MSS SP-44 – Steel Pipeline Flanges
  • MSS SP-53 – Quality Standards for Steel Castings and Forgings for Valves, Flanges and Fittings and Other Piping Components – Magnetic Particle
  • MSS SP-54 – Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components – Radiographic
  • MSS SP-55 – Quality Standards for Steel Castings and for Valves, Flanges and Fittings and Other Piping Components – Visual
  • MSS SP-75 – High Test Wrought Butt Welding Fittings
  • MSS SP-106 – Cast Copper Alloy Flanges and Flanged Fittings Class 125,150, and 300
  • ASME B16.5 and ASME B16.47 cover pipe blind flanges up to NPS 60 (B16.5 from 1/2″ to 24″ and B16.47 from 26″ to 60″). ANSI
  • B16.47 covers two series of flanges, Series A is equal to MSS SP-44-44, and Series B is equal to API 605 (API 605 has been canclled).

We are blind flange manufacturer. Flange types/pipe flange types:flange,blind flange,blank flange,slip on flange,puddle flange,pipe flange,loose flange,steel flange,weld neck flang, socket flange.The Group is also carbon steel flanges suppliers.The flange material:carbon steel,stainless steel,alloy steel. We focus on good quality flange, we are forged flanges manufacturer and ms flange manufacturer.And we have ASME,JIS, DIN flange standard. We are called din flange manufacturer and api flange manufacturer or api 6a flange manufacturer. As professional flange manufacturer, we focus on best service and nice price. Welcome to inquiry for us!