Blind flanges have the face thickness of a flange, a matching face type, and similar bolting pattern.
Material: Carbon, Alloy and Stainless Steel
Standards: ASTM A105, ASTM A182
Sizes: 1/2'' to 24'', Customized up to 48''
Thickness: Schedule 10(S) to SCH 160
Pressure Ratings: Class 150 to 2500
Face Type: RF, RTJ
1. Blind flange 2. Stud Bolt 3. Gasket 4. Other flange
The blind 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.
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.
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).
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.
Some important features of blind flanges are as follows:
Pipe 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.
Flanges are welded to pipe and equipment nozzle. Accordingly, it is manufactured from the following materials;
The list of materials used in manufacturing is covered in ASME B16.5 & B16.47.
Commonly used Forged material grads are
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.
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.
Pipe 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 flanges with top quality and soonest delivery time.
The most frequently asked questions regarding flanges and flange fittings have to do with how flanges fit on specific steel tube and steel pipe ends.
Flanges are used to connect pipes or other equipment components in various industries, and they come in a variety of materials and sizes. Flange material standards are developed by standard-setting organizations and describe the properties and characteristics of different materials that can be used to make flanges. Some examples of commonly used flange material standards include:
The choice of flange material standard will depend on various factors such as the application, the environment, the fluid being transported, and the required performance characteristics. For example, high-pressure applications may require flanges made from materials with high strength and durability, while corrosive environments may require flanges made from materials with good resistance to corrosion.
Flange Inspection
Before dispatching from manufacture each flange is inspected to ensure quality. During an inspection you have to check the following;
ASME B16.5 and B16.47 standards cover permissible tolerances for inspection.
ASME B16.5 and B16.47 standards cover permissible tolerances for inspection.
Because of the normal wooden boxes or wooden pallets have to do fumigation treatment, we usually use plywood pallet or plywood case or box to pack steel flanges without fumigation treatment.
A flange is a method of connecting pipes, valves, pumps, and other equipment to form a piping system. It also provides easy access for cleaning, inspection, or modification.
When a piping joint requires to be dismantled, flanges are being used. These are primarily used on equipment, valves, and specialty items. Breakout flanges are provided at predetermined intervals in certain pipelines where maintenance is a regular occurrence. The flanges, gaskets, and bolting make up a flanged joint, which is made up of three separate but interconnected components. To achieve a leak-proof joint, special controls are required in the selection and application of all of these elements.
Here are the details of Flanges about their advantages and their applications.