Blind Flanges
What are Blind Flanges?
Blind flanges are solid disk-shaped flanges used to close the ends of piping systems, valves, or pressure vessel openings. Without a central bore, they provide a tight seal and allow for easy inspection, maintenance, or modification of systems. Ideal for high-pressure and high-temperature environments, blind flanges are widely used across industries that demand full isolation of fluid flow.
Asiad Steel Industries is a trusted manufacturer and exporter of precision-engineered blind flanges in carbon steel, stainless steel, and alloy grades.
Key Features
Leak-Proof
Jointing
Durable
Construction
High Pressure
Resistance
Wide
Compatibility
Corrosion
Resistant
Specifications
| Specification Category | Parameter / Feature | Details / Options |
|---|---|---|
| Size Range | Nominal Pipe Size (NPS) | ½” to 48” (DN15 – DN1200) |
| Pressure Ratings | ANSI / ASME Class | Class 150, 300, 600, 900, 1500, 2500 |
| PN Ratings | PN6, PN10, PN16, PN25, PN40, PN64 | |
| Fitting Types | Blind Flanges | Weld Neck Blind, Slip-On Blind, Threaded Blind, Lap Joint Blind, Socket Weld Blind |
| Material Options | Stainless Steel | SS 304, SS 304L, SS 316, SS 316L, SS 321 |
| Carbon Steel | ASTM A105, ASTM A350 LF2 | |
| Alloy / Superalloy | Alloy Steel (A182 F1, F5, F9, F11, F22, F91), Inconel 600/625/825 | |
| Duplex & Super Duplex | Duplex 2205, Super Duplex 2507 | |
| Other Materials | Monel 400/K500, Nickel 200/201, Titanium (Grade 2, Grade 5) | |
| Standards & Certifications | ASME / ANSI | ASME B16.5, ASME B16.47 (Series A & B) |
| ASTM | ASTM A105, ASTM A182 | |
| European Standards | DIN 2527, EN 1092-1 | |
| Certifications | ISO 9001, PED 2014/68/EU, NACE MR0175, IBR Approved | |
| Design Features | Wall Thickness | As per ASME B16.5, customized options |
| Face Type | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ) | |
| Tolerance | As per ASME/ANSI standards | |
| Coating & Surface Finish | Anti-Corrosion Coating | Rust Preventive Oil, Black Oxide, Hot-Dip Galvanized |
| Optional Coatings | Epoxy, PTFE, Polyurethane | |
| Surface Finish | Machined, Pickled, Polished, Passivated | |
| Testing & Inspection | Pressure Testing | Hydrostatic, Pneumatic |
| Non-Destructive Testing | Radiography (RT), Ultrasonic (UT), Magnetic Particle (MPI), Dye Penetrant (DPT) | |
| Destructive Testing | Tensile, Hardness, Impact |
Dimensions
| NPS (in) | Class | OD (mm) | Thickness T (mm) | BCD (mm) | No. of Bolts | Bolt Size | RF Dia (mm) |
|---|---|---|---|---|---|---|---|
| ½ | 150 | 92 | 16 | 62 | 4 | ½”-13 UNC | 70 |
| ½ | 300 | 102 | 19 | 68 | 4 | ½”-13 UNC | 76 |
| ½ | 600 | 114 | 22 | 79 | 4 | ½”-13 UNC | 89 |
| ½ | 900 | 127 | 25 | 92 | 4 | ½”-13 UNC | 102 |
| ½ | 1500 | 140 | 32 | 105 | 4 | ½”-13 UNC | 114 |
| ½ | 2500 | 152 | 38 | 117 | 4 | ½”-13 UNC | 127 |
| ¾ | 150 | 102 | 16 | 70 | 4 | ½”-13 UNC | 79 |
| ¾ | 300 | 114 | 19 | 76 | 4 | ½”-13 UNC | 89 |
| ¾ | 600 | 127 | 22 | 89 | 4 | ½”-13 UNC | 102 |
| ¾ | 900 | 140 | 25 | 102 | 4 | ½”-13 UNC | 114 |
| ¾ | 1500 | 152 | 32 | 114 | 4 | ½”-13 UNC | 127 |
| ¾ | 2500 | 165 | 38 | 127 | 4 | ½”-13 UNC | 140 |
| 1 | 150 | 114 | 19 | 79 | 4 | ½”-13 UNC | 89 |
| 1 | 300 | 127 | 22 | 89 | 4 | ½”-13 UNC | 102 |
| 1 | 600 | 140 | 25 | 102 | 4 | ½”-13 UNC | 114 |
| 1 | 900 | 152 | 28 | 114 | 4 | ½”-13 UNC | 127 |
| 1 | 1500 | 165 | 32 | 127 | 4 | ½”-13 UNC | 140 |
| 1 | 2500 | 178 | 38 | 140 | 4 | ½”-13 UNC | 152 |
| 1½ | 150 | 152 | 22 | 102 | 4 | ⅝”-11 UNC | 108 |
| 1½ | 300 | 165 | 25 | 114 | 4 | ⅝”-11 UNC | 127 |
| 1½ | 600 | 178 | 28 | 127 | 4 | ⅝”-11 UNC | 146 |
| 1½ | 900 | 190 | 32 | 133 | 4 | ⅝”-11 UNC | 165 |
| 1½ | 1500 | 203 | 38 | 146 | 4 | ⅝”-11 UNC | 178 |
| 1½ | 2500 | 216 | 41 | 159 | 4 | ⅝”-11 UNC | 190 |
| 2 | 150 | 165 | 22 | 114 | 4 | ⅝”-11 UNC | 127 |
| 2 | 300 | 178 | 25 | 127 | 4 | ⅝”-11 UNC | 146 |
| 2 | 600 | 190 | 28 | 133 | 4 | ⅝”-11 UNC | 165 |
| 2 | 900 | 203 | 32 | 146 | 4 | ⅝”-11 UNC | 178 |
| 2 | 1500 | 216 | 38 | 159 | 4 | ⅝”-11 UNC | 190 |
| 2 | 2500 | 229 | 41 | 171 | 4 | ⅝”-11 UNC | 203 |
| 2½ | 150 | 190 | 25 | 133 | 4 | ⅝”-11 UNC | 146 |
| 2½ | 300 | 203 | 28 | 146 | 4 | ⅝”-11 UNC | 165 |
| 2½ | 600 | 216 | 32 | 159 | 4 | ⅝”-11 UNC | 178 |
| 2½ | 900 | 229 | 38 | 171 | 4 | ⅝”-11 UNC | 190 |
| 2½ | 1500 | 241 | 41 | 184 | 4 | ⅝”-11 UNC | 203 |
| 2½ | 2500 | 254 | 44 | 196 | 4 | ⅝”-11 UNC | 216 |
| 3 | 150 | 216 | 25 | 156 | 4 | ⅝”-11 UNC | 165 |
| 3 | 300 | 229 | 28 | 159 | 4 | ⅝”-11 UNC | 178 |
| 3 | 600 | 241 | 32 | 171 | 4 | ⅝”-11 UNC | 190 |
| 3 | 900 | 254 | 38 | 184 | 4 | ⅝”-11 UNC | 203 |
| 3 | 1500 | 267 | 41 | 196 | 4 | ⅝”-11 UNC | 216 |
| 3 | 2500 | 279 | 44 | 209 | 4 | ⅝”-11 UNC | 229 |
Mechanical Properties
| Property | Value | Unit / Standard |
|---|---|---|
| Tensile Strength | 485 – 750 | MPa (Carbon Steel, Stainless Steel, Alloy Steel) |
| Yield Strength | 170 – 450 | MPa |
| Hardness | 120 – 200 | HB (Brinell) |
| Elongation | ≥ 20 – 30 | % |
| Density | 7.8 – 8.0 | g/cm³ |
| Impact Toughness | ≥ 27 – 70 | J (Charpy, grade-dependent) |
| Modulus of Elasticity (E) | ~200 | GPa |
| Fatigue Strength | 250 – 450 | MPa |
| Corrosion Resistance | Good to Excellent | SS > CS > Alloy Steel |
| Thermal Conductivity | 15 – 50 | W/m·K |
| Coefficient of Thermal Expansion | 11 – 17 ×10⁻⁶ | /°C |
| Yield Ratio (YS/UTS) | 0.40 – 0.65 | – |
| Poisson’s Ratio | 0.27 – 0.30 | – |
| Brinell Hardness Range | 120 – 200 | HB |
| Surface Finish | Serrated / Stock / Smooth finish | ASME B16.5 |
| Welding Type | Butt-welded or Slip-on | Depending on piping system |
| Operating Temperature Range | -46 to 600 | °C (material-dependent) |
| Pressure Rating | Class 150, 300, 600, 900, 1500, 2500 | ASME B16.5 Standards |
Chemical Composition
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.08 – 0.25 |
| Manganese | 0.60 – 1.65 |
| Silicon | 0.15 – 0.80 |
| Chromium | 16.0 – 18.0 (SS) |
| Nickel | 8.0 – 10.5 (SS) |
| Molybdenum | 2.0 – 3.0 (316) |
| Iron (Fe) | Balance |
Applications of Blind Flanges
Construction &
Infrastructure
Power Generation &
Energy Sector
Manufacturing &
Fabrication
Medical & Laboratory
Equipment
Electrical &
Electronics Assembly
Oil, Gas & Petrochemical
Installations
Do you have questions?
When should I use a blind flange?
Can blind flanges handle high pressure?
Are they available in different materials?
Do blind flanges allow system access for maintenance?
