Blind Flanges Manufacturers, Supplier and Exporter in India

Blind Flanges Specification, Grades, and Material

About Blind Flanges

A blind flange is also called a blind disk or flanged pipe plug. in Blind flange, there are no holes in the center, to seal the pipe opening. So its operation is the same as the pipe cap or the pipe plug. The difference from other flange is detachable equipment, easy to replace or do maintenance.
Major Function – Where to use
The major function of blind flanges is totally to separate the production medium. Which prevents the shut-off valve from closing not fast, then affecting production, and even causing accidents.
The location where it needs isolation should place the blind flange, such as at the equipment nozzle. Between the two flanges or between the front and rear of the shut-off valve, it is often suggested to use a figure 8 blind flange (figure-8 blank); For single-use parts such as pressing and purging usually use a common round blind flange.
Sealing Surface
There are different types of sealing surfaces, such as flat, grooved surface, concave, convex, and ring joint surfaces.

Material Types and Standards

Materials of Blind Flange usually required in stainless steel, carbon steel, aluminum, alloy steel, copper, and etc.

• Carbon steel blind flange: ASTM A105
• Alloy steel: ASTM A182 F5, F9, F11, F22, F91
• Stainless steel blind flange: ASTM A182 F304/L, F316/L

Manufacturing Standards

• ASME B16.5
• BS 3293
• DIN 86029

Dimensions

• General use OD range: 1/2”, 2”, 3”, 4”, 6”, 8”, 10”, 12”, to 24”.
• Special made OD: Up to 60”.
• Class range: Class 150, Class 300, 400, 600, 900, 1500, 2500
• Flange face type: RF (Raised Face), RTJ (Ring Type Joint)

Manufacturing Types and Costs

Generally has four types: casting and forging, medium plate cutting, Forging, 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 method when compared with others.
The best quality is forging and medium plate, casting, and the forging could be a bit worse.
Casting Blind Flange
The shape of the casting flange blank is accurate, has a 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 flanges typically have lower carbon content than cast flanges and are not easy to rust. Forgings have denser structure, better-streamlined shape, and better mechanical properties than the cast flanges;
If the forging method is improper, the grain can be big or uneven, and the hardening crack will occur. The casting flange cost is lower than the forging.
Precautions When Use
Under the premise of meeting the method requirements, use as few blind plates as possible.
The blind plate set must be marked as usually open or usually closed.
The location of the blind plate is determined by the safety, cutting effect, and process requirements.