Blind Flange

Purpose, Significance and Considerations

The purpose of Stainless steel Blind Flange is to close ends of piping systems. It is a type of round plate with perfect bolt holes at corner but no centre hold. To prepare positive closer use ANSI B16.5 blind flanges on the ends of equipment nozzles, valves and pipes. While sealing the line theses flange provides easy access to it. The blind pipe flange can be sometimes machined or custom made for quickly acquiring a nominal pipe size. The reduction being made to pipe can be welded or threaded depending upon the need. The abbreviation of blind is BL Flange which have implementation in industries that uses piping.

It is a piping element for closing or casing the end of a valve, pipe, tank or vessel. When implemented at the end of a pipe, tank or vessel, it yield an effortless open entrance for furthermore supplement of the pipe. The bolts of blind flanges are emphasized more than any other flange, becuase it’s sole objective is to undergo the pressure of pipe.

On completion of expansion for bolting on pipe a ss blind flange can be used, when designing a piping system. This design allows for continuation or expansion of the pipeline by simply connectingg to the last flange. If used on a manifold in dirty service a blind steel flange can be used by the operations and maintenance staff to clean out or inspect the piping during a shutdown.

What is the use of a blind flanges?

A Piping designer must place blind flange at the junction or at the pipe end in that direction. For high pressure implementation BL Pipe Flange are of much benefit. At the construction stage piping is easier to drill or weld. Once it is in use, drilling or welding will need prolong cleaning especially when the fluid transferred is combustible. To seal the end for future extension, one should use blind or valve. To allow bolting on piping,  use a blind flange when the expansion is accomplished. A blind can be placed across two flanges to stop flow but this isn’t good execution in most piping. When trying to stop flow temporarily in a pipe, the enngineer should use a spectacle blind fange instead.

To avoid the coincidental opening of a valve, please use blind flange at the end  which will not cause an decamp of the process fluid. First consider how the blind flange will be removed before placig it. It may require the addition of a lifting eye for a crane or a specially designed davit to hold the flange in place after the bolts are removed. Care should be taken in that the davit must be designed to be able to hold the entire weight of the flange.

ASME / ANSI B16.5 Blind Flange Manufacturer In India

Devdeep Steel Alloys is a specialised manufacturers of high quality pipe blind flange available in standards ANSI B16.5 Flanges, ANSI B16.47 Series A & B, DIN Flange, JIS B2220 flange, MSS SP44 Flange, EN1092-1 FLANGES, API 605, AWWA C207 Flange, industrial pipe flanges in India. We quickly provide the standard size of stainless steel flanges and carbon steel flanges because of ready stock facility. ANSI B16.5 Blind Steel flange have generally pressure ratings as follows. 150 lb, 300 lb, 400 lb, 600 lb, 900 lb, 1500 lb, 2500 lb. We also manufacture plate blind flanges from special nickel alloy steel grades. The material is provided within few working days in time programs.

Our blind pipe flange are available with face type of Flat Face (BLFF), Raised Face (BLRF) & Ring Type Joint (BLRTJ) and also with female threads. Steel Blind flanges are also available with or without hub as per the requirement of customer. Devdeep Steel Alloys offer steel plate flanges to all companies coupled with various industries. For instance petrochemical plants, paper mills, power generation, pharmaceutical plants, oil refineries, shipbuilding, turnkey projects and waste water treatment plants among others.

Blind pipe flanges are comparatively used where high & huge pressure applications are needed. To allow an easy access, in a piping system you should use blind steel flanges only one time when it is closed. At the present time we design SS Blind flange with advance technology made from raw material of high quality, that have low maintenance. Moreover the products are available at very fair & competitive price.

Types Of Pipe Flange

Slip-on flange, weld neck flange, threaded flange, socket weld flange, blind flange, lap joint flange are the most common types of steel flanges. The special flanges such as orifice flanges, long weld neck flanges, spectacle flange to cater all industrial needs. In fact steel pipe flange are manufactured according to international quality standards which are available in various material, sizes & dimensions. In hazardous welding areas where the situation is extraordinary and areas are highly volatile. For that reason one can use our pipe flanges as an advantage in working those circumstances. Thereupon we timely deliver the products within stipulated time frame. High durability, corrosion resistance technique as well as dimensional accuracy are the advantages of our products. Our range of flanges consequently got approval in the global and the domestic markets

Carbon Steel / Stainless Steel Blind Forged Flanges Production Range

Size: 1/2″ (15 NB) to 48″ (1200NB)

Standards: ANSI B16.5 Flanges, ANSI B16.47 Series A & B, DIN Flange, JIS B2220 flange, MSS SP44 Flange, EN1092-1 FLANGES, ASA, API 605, AWWA C207 Flange.

Pressure Ratings: Class 150, Class 300, Class 400, Class 600, Class 900, Class 1500, Class 2500. PN6, PN10, PN16, PN25, PN40, PN64 etc.

Carbon Steel Blind Flanges: A350 LF1, LF2, LF3 CL1/CL2.

A694 F42, F46, F48, F50, F52, F56, F60, F65, F70, A516.60, 65, 70. Steel RST37.2, C22.8

Stainless Steel Blind Flanges: ASTM A182 F202, F304/304L/304H, F316/316L, F316H, F316TI, F310, F321, F904L.

Alloy Steel Blind Flanges: ASTM A182 F1, F5, F9, F11, F22, F91.

Nickel Alloy Blind Flanges:Alloy C22, C276, A400, A600, A625, A800 & A825 / ASTM B462 Alloy 20.

Flange Face Type: Flat Face Flanges (FF), Raised Face Flange (RF), Groove and Tongue, Ring Type Joint (RTJ)

Coating/Surface Treatment: Oil Black Paint, Anti-rust Paint, Yellow Transparent, Cold and Hot Dip Galvanised, Zinc Plated.

Value Added Services: Customised Flanges & CNC Machining.

Dimensional Tolerances of Blind Flanges

Ansi B16.5 blind flange dimension

Outside Diameter
≤ 24 = 1.6 mm | > 24 = ± 3.2 mm
Inside Diameter
not applicable
Diameter of Contact Face
1.6 mm Raised Face = ± 0.8 mm
6.35 mm Raised Face, Tongue & Groove / Male-Female = ± 0.4 mm
Outside Diameter of Hub
≤ 12 = + 2.4 mm / – 1.6 mm | ≥ 14 = ± 3.2 mm
Diameter of Counterbore
not applicable
Bolt Circle = 1.6 mm | Bolt Hole Spacing = ± 0.8 mm
Eccentricity of Bolt Circle with Respect to Facing
≤ 2½ = 0.8 mm max. | ≥ 3 = 1.6 mm max.
≤ 18 = + 3.2 mm / – 0
≥ 20 = + 4.8 mm / – 0
Length thru Hub
≤ 18 = + 3.2 mm / – 0.8 mm
≥ 20 = + 4.8 mm / – 1.6 mm


  • Blind Raised Face Flange
    • ANSI Class 150, B16.5, RF (in)
    • ANSI Class 300, B16.5, RF (in)
    • ANSI Class 400, B16.5, RF (in)
    • ANSI Class 600, B16.5, RF (in)
    • ANSI Class 900, B16.5, RF (in)
    • ANSI Class 1500, B16.5, RF (in)
    • ANSI Class 2500, B16.5, RF (in)
  • Blind Ring Type Joint Flange
    • ANSI Class 150, B16.5, RTJ (in)
    • ANSI Class 300, B16.5, RTJ (in)
    • ANSI Class 400, B16.5, RTJ (in)
    • ANSI Class 600, B16.5, RTJ (in)
    • ANSI Class 900, B16.5, RTJ (in)
    • ANSI Class 1500, B16.5, RTJ (in)
    • ANSI Class 2500, B16.5, RTJ (in)


  • ANSI B16.47 Series A
    • ANSI Class 150, B16.47 Series A (in)
    • ANSI Class 300, B16.47 Series A (in)
    • ANSI Class 400, B16.47 Series A (in)
    • ANSI Class 600, B16.47 Series A (in)
    • ANSI Class 900, B16.47 Series A (in)
  • ANSI B16.47  Series B
    • ANSI Class 150, B16.47 Series B (in)
    • ANSI Class 300, B16.47 Series B (in)


  • ANSI Class 75, Industry Standard (For SOF) (in)
  • ANSI Class 75, Industry Standard (For WNF) (in)
  • ANSI Class 250, Industry Standard (in)
  • ANSI Class 350, Industry Standard (in)

Marking & PackagingSteel Flange Marking & Packaging

We deliver blind flanges from our warehouse to your workplace with complete protection in the meantime. The unforeseen accidents can damage the product during delivery, therefore we pack them in wooden pallet. In case of exports, we use wooden cases for standard export packaging. We take great care of product during transportation and operation. To clarify details, we clearly label the products regarding quality, quantity and product I.D outside the package. To prevent damage during transportation, Devdeep cover the product in plastic bags and close them in cartoon boxes. Furthermore we also provide seaworthy wooden cases plywood boxes according to the requirement of customer.

The Blind, BL Flanges contains marking such as Lot no, Steel Grade, outside diameter, Size & dimension, Wall thickness including Devdeep Steel Alloys Brand Mark. For customised marking you can contact us. We guarantee the fastest delivery for products in country, because of well equipped storage and warehouse facilities.

Quality Assurance & Test Certificates:

We undertake strict inspection at each stage in the process of production of blind flanges. At Devdeep Steel Alloys from purchasing of material to dispatch the product contains no defect. Our team member frequently examine the flange to confirm the international quality, codes and standards. ASTM, ASME (American), MSS, DIN German), EN (European), JIS (Japanese). To confirm the quality of products, to witness the dimension & material reports. We can call a certified Third Party Inspection agencies upon request. At Devdeep Steel Alloys, the clients can nominate Third Party Inspection for offered products. We can also arrange the TPI by World reputed Agencies like LLOYDS, DNV, ICB, Bureau Veritas and many other.

We use high quality raw material for manufacturing steel blind flange tested from approved NABL Lab. Other testing reports such as Non Destructive or destructive and Hydro Testing Reports can be provided upon request of customer,

Manufacturer Test Certificate (MTC) as per EN 10204 / 3.1B will be provided along with the ANSI B16.5 Blind Flanges. In addition 100% Radiography Test Report, Raw Materials Certificate & Third Party Inspection Report available on demand.