Thread Flange Screwed flange NPT

Thread Pipe Flange Screwed flange

Threaded Flange (Thread Flange)

A Threaded Flange (also called Screwed Flange) is a type of flange that is connected to a pipe without welding, using internal threads that match the external threads on the pipe.

Key Features of Threaded Flanges

  • Connection Type: Internal threads (typically NPT or BSPT)
  • No Welding Required: Ideal for systems where welding is not possible or desirable
  • Material: Commonly made from carbon steel, stainless steel, alloy steel
  • Pressure Ratings: ANSI/ASME Class 150 to 2500
  • Design Standard: ASME B16.5 (for sizes up to 24 inches)

Threaded Flange Materials We Offer

StandardMaterial Grade
Carbon SteelASTM A105A350 LF2A694 F52/F60/F65
Stainless SteelASTM A182 F304/L, F316/L, F321, F347, F51, F53, F55
Alloy SteelASTM A182 F11, F12,F22, F5, F9, F91
Nickel AlloysInconel 625, Incoloy 825, Hastelloy C276
Duplex / Super DuplexUNS S31803, S32205, S32750, S32760
Special Materials904L (1.4539), Monel 400, Titanium, Aluminum, Copper-Nickel

Manufacturing & Testing for Thread Flange

  • Forged blank
  • CNC machining
  • Heat treatment: Normalizing, Quenching + Tempering, Annealing
  • NDT: UT / PT / MT / RT
  • PMI, hydrostatic testing, hardness & impact testing (on request)
  • MTC: EN 10204 3.1 / 3.2, Third-party inspection (TÜV, SGS, BV)

Design Standards for thread flange

Threaded flanges are manufactured according to the following internationally recognized standards:

StandardDescription
ASME B16.5Pipe flanges and flanged fittings, NPS ½” – 24”, Class 150–2500
DIN DIN 2565–2569DIN Threaded flange
BS 4504 / EN 1092-1Threaded flange

Flange Thread Types

Thread TypeStandardApplication
NPTANSI/ASME B1.20.1National Pipe Tapered Thread (U.S.)
BSPTISO 7-1 / EN 10226British Standard Pipe Tapered Thread
Metric ThreadISO 261 / ISO 965Metric pipe thread (less common)
Threaded flange

THREADED CLASS 150 Dimension ASME B16.5

Threaded Flange Dimensions ASME B16.5
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HRaised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.93″3.50″2.38″1.38″.063″1.19″.62″.38″.56″.62″4
3/4″1.14″3.88″2.75″1.69″.063″1.50″.62″.44″.56″.62″4
1″1.41″4.25″3.12″2.00″.063″1.94″.69″.50″.63″.62″4
1-1/4″1.75″4.62″3.50″2.50″.063″2.31″.81″.56″.75″.62″4
1-1/2″1.99″5.00″3.88″2.88″.063″2.56″.88″.62″.82″.62″4
2″2.50″6.00″4.75″3.62″.063″3.06″1.00″.69″.94″.75″4
2-1/2″3.00″7.00″5.50″4.12″.063″3.56″1.12″.82″1.06″.75″4
3″3.63″7.50″6.00″5.00″.063″4.25″1.19″.88″1.13″.75″4
3-1/2″4.13″8.50″7.00″5.50″.063″4.81″1.25″.88″1.19″.75″8
4″4.63″9.00″7.50″6.19″.063″5.31″1.31″.88″1.25″.75″8
5″5.69″10.00″8.50″7.31″.063″6.44″1.44″.88″1.38″.88″8
6″6.75″11.00″9.50″8.50″.063″7.56″1.56″.94″1.50″.88″8
8″8.75″13.50″11.75″10.62″.063″9.69″1.75″1.06″1.69″.88″8
10″10.88″16.00″14.25″12.75″.063″12.00″1.94″1.13″1.88″1.00″12
12″12.94″19.00″17.00″15.00″.063″14.38″2.19″1.19″2.13″1.00″12
14″14.19″21.00″18.75″16.25″.063″15.75″2.25″1.32″2.19″1.12″12
16″16.19″23.50″21.25″18.50″.063″18.00″2.50″1.38″2.44″1.12″16
18″18.19″25.00″22.75″21.00″.063″19.88″2.69″1.50″2.63″1.25″16
20″20.19″27.50″25.00″23.00″.063″22.00″2.88″1.63″2.83″1.25″20
22″22.19″29.50″27.25″25.25″.063″24.25″3.13″1.75″3.07″1.38″20
24″24.19″32.00″29.50″27.25″.063″26.12″3.25″1.82″3.19″1.38″20

THREADED CLASS 300

Threaded flange dimensions class 300 in inches (ASME B16.5)

Threaded Flange Dimensions ASME B16.5
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HRaised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.93″3.75″2.62″1.38″.063″1.50″0.88″0.50″0.82″0.62″4
3/4″1.14″4.62″3.25″1.69″.063″1.88″1.00″.056″0.94″0.75″4
1″1.41″4.88″3.50″2.00″.063″2.12″1.06″0.63″1.00″0.75″4
1-1/4″1.75″5.25″3.88″2.50″.063″2.50″1.06″0.69″1.00″0.75″4
1-1/2″1.99″6.12″4.50″2.88″.063″2.75″1.19″0.75″1.13″0.88″4
2″2.50″6.50″5.00″3.62″.063″3.31″1.31″0.82″1.25″0.75″8
2-1/2″3.00″7.50″5.88″4.12″.063″3.94″1.50″0.94″1.44″0.88″8
3″3.63″8.25″6.62″5.00″.063″4.62″1.69″1.06″1.63″0.88″8
3-1/2″4.13″9.00″7.25″5.50″.063″5.25″1.75″1.13″1.69″0.88″8
4″4.63″10.00″7.88″6.19″.063″5.75″1.88″1.19″1.82″0.88″8
5″5.69″11.00″9.25″7.31″.063″7.00″2.00″1.32″1.94″0.88″8
6″6.75″12.50″10.62″8.50″.063″8.12″2.06″1.38″2.00″0.88″12
8″8.75″15.00″13.00″10.62″.063″10.25″2.44″1.56″2.38″1.00″12
10″10.88″17.50″15.25″12.75″.063″12.62″2.62″1.82″2.56″1.12″16
12″12.94″20.50″17.75″15.00″.063″14.75″2.88″1.94″2.82″1.25″16
14″14.19″23.00″20.25″16.25″.063″16.75″3.00″2.06″2.94″1.25″20
16″16.19″25.50″22.50″18.50″.063″19.00″3.25″2.19″3.19″1.38″20
18″18.19″28.00″24.75″21.00″.063″21.00″3.50″2.32″3.44″1.38″24
20″20.19″30.50″27.00″23.00″.063″23.12″3.75″2.44″3.69″1.38″24
22″22.19″33.00″29.25″25.25″.063″25.25″4.00″2.57″3.94″1.63″24
24″24.19″36.00″32.00″27.25″.063″27.62″4.19″2.69″4.13″1.62″24

THREADED CLASS 400

Threaded flange dimensions class 400 in inches (ASME B16.5)

Threaded Flange Dimensions ASME B16.5
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HRaised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.93″3.75″2.62″0.12″.250″1.50″1.13″0.56″0.88″0.62″4
3/4″1.14″4.62″3.25″0.12″.250″1.88″1.25″0.62″1.00″0.75″4
1″1.41″4.88″3.50″0.12″.250″2.12″1.31″0.69″1.06″0.75″4
1-1/4″1.75″5.25″3.88″0.19″.250″2.50″1.37″0.81″1.12″0.75″4
1-1/2″1.99″6.12″4.50″0.25″.250″2.75″1.50″0.88″1.25″0.88″4
2″2.50″6.50″5.00″0.31″.250″3.31″1.69″1.00″1.44″0.75″8
2-1/2″3.00″7.50″5.88″0.31″.250″3.94″1.87″1.12″1.62″0.88″8
3″3.63″8.25″6.62″0.38″.250″4.62″2.06″1.25″1.81″0.88″8
3-1/2″4.13″9.00″7.25″0.38″.250″5.25″2.19″1.38″1.94″1.00″8
4″4.63″10.00″7.88″0.44″.250″5.75″2.25″1.38″2.00″1.00″8
5″5.69″11.00″9.25″0.44″.250″7.00″2.37″1.50″2.12″1.00″8
6″6.75″12.50″10.62″0.50″.250″8.12″2.50″1.62″2.25″1.00″12
8″8.75″15.00″13.00″0.50″.250″10.25″2.94″1.88″2.69″1.12″12
10″10.88″17.50″15.25″0.50″.250″12.62″3.13″2.12″2.88″1.25″16
12″12.94″20.50″17.75″0.50″.250″14.75″3.37″2.25″3.12″1.38″16
14″14.19″23.00″20.25″0.50″.250″16.75″3.56″2.38″3.31″1.38″20
16″16.19″25.50″22.50″0.50″.250″19.00″3.94″2.50″3.69″1.50″20
18″18.19″28.00″24.75″0.50″.250″21.00″4.13″2.62″3.88″1.50″24
20″20.19″30.50″27.00″0.50″.250″23.12″4.25″2.75″4.00″1.62″24
22″22.19″33.00″29.25″0.50″.250″25.25″4.50″2.88″4.25″1.75″24
24″24.19″36.00″32.00″0.50″.250″27.62″4.75″3.00″4.50″1.88″24

THREADED CLASS 600

Threaded flange dimensions class 600 in inches (ASME B16.5)

Threaded Flange Dimensions ASME B16.5
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HRaised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.93″3.75″2.62″1.38″.250″1.50″1.13″0.56″0.88″0.62″4
3/4″1.14″4.62″3.25″1.69″.250″1.88″1.25″0.62″1.00″0.75″4
1″1.41″4.88″3.50″2.00″.250″2.12″1.31″0.69″1.06″0.75″4
1-1/4″1.75″5.25″3.88″2.50″.250″2.50″1.37″0.81″1.12″0.75″4
1-1/2″1.99″6.12″4.50″2.88″.250″2.75″1.50″0.88″1.25″0.88″4
2″2.50″6.50″5.00″3.62″.250″3.31″1.69″1.00″1.44″0.75″8
2-1/2″3.00″7.50″5.88″4.12″.250″3.94″1.87″1.12″1.62″0.88″8

THREADED CLASS 900

Threaded flange dimensions class 900 in inches (ASME B16.5)

Threaded Flange Dimensions ASME B16.5
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HRaised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.93″4.75″3.25″1.38″.250″1.50″1.50″0.88″1.25″0.88″4
3/4″1.14″5.13″3.50″1.69″.250″1.75″1.63″1.00″1.38″0.88″4
1″1.41″5.88″4.00″2.00″.250″2.06″1.88″1.13″1.63″1.00″4
1-1/4″1.75″6.25″4.38″2.50″.250″2.50″1.88″1.13″1.63″1.00″4
1-1/2″1.99″7.00″4.88″2.88″.250″2.75″2.00″1.25″1.75″1.13″4
2″2.50″8.50″6.50″3.63″.250″4.13″2.50″1.50″2.25″1.00″8
2-1/2″3.00″9.63″7.50″4.13″.250″4.88″2.75″1.63″2.50″1.13″8
3″3.63″9.50″7.50″5.00″.250″5.00″2.38″1.50″2.13″1.00″8
4″4.63″11.50″9.25″6.19″.250″6.25″3.00″1.75″2.75″1.25″8
5″5.69″13.75″11.00″7.31″.250″7.50″3.38″3.00″3.13″1.38″8
6″6.75″15.00″12.50″8.50″.250″9.25″3.63″2.19″3.38″1.25″12
8″8.75″18.50″15.50″10.63″.250″11.75″4.25″2.50″4.00″1.50″12
10″10.88″21.50″18.50″12.75″.250″14.50″4.50″2.75″4.25″1.50″16
12″12.94″24.00″21.00″15.00″.250″16.50″4.88″3.13″4.63″1.50″20
14″14.19″25.25″22.00″16.25″.250″17.75″5.38″3.38″5.13″1.63″20
16″16.19″27.75″24.25″18.50″.250″20.00″5.50″3.50″5.25″1.75″20
18″18.19″31.00″27.00″21.00″.250″22.25″6.25″4.00″6.00″2.00″20
20″20.19″33.75″29.50″23.00″.250″24.50″6.50″4.25″6.25″2.13″20
24″24.19″41.00″35.50″27.25″.250″29.50″8.25″5.50″8.00″2.63″20

THREADED CLASS 1500

Threaded flange dimensions class 1500 in inches (ASME B16.5)

Threaded Flange Dimensions ASME B16.5
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HRaised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.93″4.75″3.25″1.38″.250″1.50″1.50″0.88″1.25″0.88″4
3/4″1.14″5.13″3.50″1.69″.250″1.75″1.63″1.00″1.38″0.88″4
1″1.41″5.88″4.00″2.00″.250″2.06″1.88″1.13″1.63″1.00″4
1-1/4″1.75″6.25″4.38″2.50″.250″2.50″1.88″1.13″1.63″1.00″4
1-1/2″1.99″7.00″4.88″2.88″.250″2.75″2.00″1.25″1.75″1.13″4
2″2.50″8.50″6.50″3.63″.250″4.13″2.50″1.50″2.25″1.00″8
2-1/2″3.00″9.63″7.50″4.13″.250″4.88″2.75″1.63″2.50″1.13″8

THREADED CLASS 2500

Threaded flange dimensions class 2500 in inches (ASME B16.5)

Threaded Flange Dimensions ASME B16.5
FLANGE
NPS
Inside
Diameter
Outside
Diameter
Bolt Circle (BC)Raised Face (R)Raised Face (RF)HRaised Face Thickness (T)T1Flat Face Thickness (T2)Bolt Hole (B)No. of Bolt Holes
1/2″0.93″5.25″3.50″1.38″.250″1.69″1.81″1.19″1.56″0.88″4
3/4″1.14″5.50″3.75″1.69″.250″2.00″1.94″1.25″1.69″0.88″4
1″1.41″6.25″4.25″2.00″.250″2.25″2.13″1.38″1.88″1.00″4
1-1/4″1.75″7.25″5.13″2.50″.250″2.88″2.31″1.50″2.06″1.13″4
1-1/2″1.99″8.00″5.75″2.88″.250″3.13″2.63″1.75″2.38″1.25″4
2″2.50″9.25″6.75″3.63″.250″3.75″3.00″2.00″2.75″1.13″8
2-1/2″3.00″10.50″7.75″4.13″.250″4.50″3.38″2.25″3.13″1.25″8