Stainless Steel Pipe Fittings

Threaded Flanges (TH Flanges) By

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Threaded Flanges (TH Flanges) By

Threaded flanges (TH Flanges) look very similar to Slip-On flanges but the main difference is that the threaded flange has been was bored out to match a specific pipe inside diameter. The backside of this center opening is then threaded with the relevant-sized tapered pipe thread.

Threaded Flanges (TH Flanges) are used for special circumstances with their main advantage being that they can be attached to the pipe without welding. Threaded flanges are threaded in the bore which match an external thread on the pipe. These threads are tapered in order to create a seal between the threaded flange and the pipe as the tapers approach the same diameter. Sometimes a seal weld is also used together with the threaded connection. This special type of flange is generally used for high pressure, yet smaller diameter applications. Obviously, the larger the flange is, the harder the ability to machine a thread would be. Threaded flanges are also not a good choice for a system that has a high level of torque.


Size: 1/2” to 60”, DN 12mm to DN 1500mm 
Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
Facing: RF / RTJ

Dimensions are in millimeters unless otherwise indicated.


≤ 24 = 1.6 mm
> 24 = ± 3.2 mm


≤ 10 = ± 0.8 mm
≥ 12 = + 1.6 mm / – 0 mm


1.6 mm Raised Face = ± 0.8 mm
6.35 mm Raised Face
Tongue & Groove

Male-Female = ± 0.4 mm


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.


Same as for Inside Diameter


≤ 12 = + 2.4 mm / – 1.6 mm
≥ 14 = ± 3.2 mm


≤ 18 = + 3.2 mm / – 0
≥ 20 = + 4.8 mm / – 0


≤ 18 = + 3.2 mm / – 0.8 mm
≥ 20 = + 4.8 mm / – 1.6 mm

These Threaded Flanges (TH Flanges) are available in the following range.

Stainless Steel: ASTM A182 F304, F304L, F304H, F316, F316L, F316Ti, F310, F310S, F321, F321H, F317, F347, F347H, F904L. 
Duplex Stainless Steel: UNS S31803, UNS S32750 
Carbon Steel: ASTM A105, 
Alloy Steel: ASTM A182 F1, F11, F22, F5, F9, F91 
Nickel Alloys: Monel 400 & 500, Inconel 600 & 625, Incoloy 800, 825, Hastelloy C22, C276 
Copper Alloys: Copper, Brass & Gunmetal 
Size: 1/8″ NB TO 48″NB. 
Class: 150#, 300#, 400#, 600#, 900#, 1500#, 2500# 

Dimensional Standard

ANSI: ANSI B16.5, ANSI B16.47, MSS SP44, ANSI B16.36, ANSI B16.48 
DIN: DIN 2527, DIN 2566, DIN 2573, DIN 2576, DIN 2641, DIN 2642, DIN 2655, DIN 2656, DIN 2627, DIN 2628, DIN 2629, DIN 2631, DIN 2632, DIN 2633, DIN 2634, DIN 2635, DIN 2636, DIN 2637, DIN 2638, DIN 2673 

B.S: BS 4504, BS4504, BS1560, BS10

Standards, Dimensions & Weight
  • ASME/ANSI B16.5 Class 150 TH
  • ASME/ANSI B16.5 Class 300 TH
  • ASME/ANSI B16.5 Class 600 TH
  • ASME/ANSI B16.5 Class 900 TH
  • DIN 2565 PN6
  • DIN 2566 PN10

Uses of threaded flanges (TH Flanges) :

  • Threaded flanges can be fitted to pipes of various sizes without welding and this is one chief benefit for which these flanges are highly demanded.
  • They can be used in extremely high pressure applications, particularly at or near atmospheric temperature, where the necessary post weld heat treatment is not possible.
  • They are ideal for small diameter piping applications.
  • They are economical and time saving devices.
  • These threaded flanges are normally designed for non-cyclic applications.
  • The flanges are suitable to be used in applications where welding is hazardous.
  • They can be used in highly explosive areas.

The various types of threaded flanges (TH Flanges) are as follows:

  • Plain Threaded Flanges
  • Female Threaded Flanges
  • Male Threaded Flanges
SS Threaded Flange CS Threaded Flange Alloy Steel Threaded Flange F5 Threaded Flange
F11 Threaded Flange F22 Threaded Flange F12 Threaded Flange F91 Threaded Flange
SS 304 Threaded Flange SS 304L Threaded Flange SS 316 Threaded Flange SS 316 L Threaded Flange
SS 317 Threaded Flange SS 317L Threaded Flange SS 321 Threaded Flange SS 347H Threaded Flange
SS 904L Threaded Flange Duplex Threaded Flange Super Duplex Threaded Flange S31803 Threaded Flange
S32205 Threaded Flange Monel 400 Threaded Flange Monel K500 Threaded Flange Inconel Threaded Flange
Duplex Threaded Flange Super Duplex Threaded Flange S32750 Threaded Flange S32760 Threaded Flange
F51 Threaded Flange F53 Threaded Flange A694 F42 Threaded Flange A694 F46 Threaded Flange
A694 F52 Threaded Flange A694 F56 Threaded Flange A694 F60 Threaded Flange A694 F65 Threaded Flange
A694 F70 Threaded Flange A350 LF2 Threaded Flange A350 LF3 Threaded Flange A707 L1 Threaded Flange
A707 L2 Threaded Flange A707 L3 Threaded Flange A105 Threaded Flange F904L Threaded Flange
Inconel 625 Threaded Flange Incoloy 800 Threaded Flange Incoloy 800H Threaded Flange Incoloy 800HT Threaded Flange
Hastelloy Threaded Flange Hastelloy B2 Threaded Flanges Hastelloy B3 Threaded Flange Hastelloy C22 Threaded Flange
Hastelloy C276 Threaded Flange KOC approved Threaded Flange KNPC approved Threaded Flange AAramco approved Threaded Flange

Source: Zhejiang Yaang Pipe Industry Co., Limited (

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