HG/T 20592-2009Steel Pipe Flanges (English PDF)

3.1 Flange type

3.1.1 The flange type and its code are in accordance with those specified in Figure 3.1.1 and Table 3.1.1. […]

3.2 Flange seal contact face

3.2.1 The mode and code of the seal contact face of the flange are in accordance with those specified in Figure 3.2.1 and Table 3.2.1. The mode of the seal contact face of the flange includes: raised face (RF), male-female face (MFM), tongue and groove face (TG), flat face (FF) and ring joint face (RJ).

3.2.2 Mode applicability of flange seal contact face types is in accordance with those specified in Table 3.2.2.

3.2.3 Roughness of flange sealing surface

1 The flange seal contact face shall be made with machine work, and the roughness of surface is in accordance with those specified in Table 3.2.3-1. When the flange seal contact face is customer-oriented, it shall be indicated when ordering.

2 The flange seal contact face defects shall not exceed the scope specified in Table 3.2.3-2. The distance between any two adjacent defects shall be more than or equal to 4 times of the maximum radial dimension of the defect, and bulge flange seal contact face defect is not allowed.

Note: Such seal contact face as raised face, male-female face and flat face is a sort of serrate concentric circle or helical tooth groove formed naturally when being processed with processing cutters. Fillet radius of the processing cutter shall not be less than 1.5mm, while groove depth of the formed serrate concentric circle or helical tooth is about 0.05mm, the pitch is about 0.45~055mm.

Note: 1 The radial projection dimension of the defect is the difference between the maximum radius and minimum radius of the defect away from the flange hole center. 2 h is the groove depth of serrate concentric circle or helical tooth of the flange seal contact face.

3.2.4 Supporting surface of the bolt

1 The supporting surface of the bolt shall be made with machine work or counter boring (fisheye hole). Counter boring dimension is in accordance with those specified in GB/T 152.4, and the parallelism between the supporting surface of the bolt and the seal contact face shall be in accordance with those specified in Table 10.0.1 of this Standard. 2 After the machine work or counter boring on the supporting surface of the bolt, flange thickness shall be ensured to be in accordance with the requirements of dimension tolerance specified in Table 10.0.1 of this Standard. 3 The following flanges adopting B series outside diameter of the steel pipe shall be on the bolt supporting surface of the flange, based on the center of bolt hole, and counter boring face with diameter similar to that listed in Table 3.2. […]

4.0.4 Stainless steel lining blind flange (BL<S>)

1 The backing layer and blind flange shall be compacted tightly and welding according to the requirements of Figure 4.0.4 and JB/T 4709. The welding material on the fillet weld and plug welding hole bottom layer is adopted according to transition layer welding rod, while the facing welding material is adopted according to welding rod on the capping layer. The plug welding is in accordance with those specified in Table 4.0.4. 3 The maximum allowable working pressure under nominal pressure and working temperature of the Lining Blind Flange (BL<S>) complies with the requirements of Chapter 7 according to Blind Flange (BL) material sorts. While the upper limit for the service temperature of the stainless steel lining blind flange is no greater than 350℃. 4 The Blind Flange (BL) shall be opened with a M6 ventilating hole and gauged orifice, while their positions are set by themselves. After plug welding, let in compressed air with pressure of no greater than 0.1MPa for leak hunting, or gauged orifices with other dimensions may be opened according to the conditions of the manufactory. 5 The thickness tolerance of backing layer thickness t is -1mm. 4.0.5 Unless otherwise specified in this Standard, the materials for pipe flange shall also comply with the requirements of relevant standards and codes. 5.0.1 The gasket shall comply with the sealing property of flange joint under working conditions. Acting by pretension load of bolt, gasket stress under pretension and working conditions shall be ensured, and no deleterious deformation or crush can be generated. 5.0.2 The gasket complies with the requirements of HG/T 20606~HG/T 20612. 5.0.3 The bolting includes hex bolt, double end studs (tamping type), full thread stud and nut, the applied bolt quantity and specification are in accordance with the requirements of Table 8.1.1 shown in this Standard. 5.0.4 The bolting is classified into high strength, medium strength and low strength. The bolting materials shall be adopted according to the gasket, pressure, temperature, flange and sealing face mode, so as to meet the requirements of the sealing property and bearing strength of flange joint under pretension and working conditions. 5.0.5 The bolting complies with the requirements of HG/T 20613. The fitting between the flange and gasket or bolting complies with the requirements of HG/T 20614. 7.0.1 For the steel pipe flange and blind flange with nominal pressure grade of PN2.5~PN160, the maximum allowable working pressure under working temperature complies with the requirements of Table 7.0.1-1~Table 7.0.1-9. The medium temperature may be determined by interpolation method. 7.0.2 The sorts of pipe flange materials listed in Table 7.0.1-1~Table 7.0.1-9 comply with the requirements of Table 4.0.1 of this Standard. 7.0. […]

8.1 Flanged coupling dimension

8.1.1 The coupling dimension of the flange complies with the requirements of Figure 8.1.1 and Table 8.1.1 (they are flanges have their different pressure grades within mourning border of table 8.1.1, but they are equipped with same coupling dimension). The domestic and international flanges standards assorted with this Standard may refer to Appendix C of this Standard.

8.1.2 The bolt holes shall be evenly distributed.

4 bolt holes may also be adopted, and they shall be supplied according to the agreement signed between the manufacturer and the purchaser.

The coupling dimensions of PN10~40 and DN80 flange are identical.

8.3 Flange neck

8.3.1 The outer flank slope for the neck of the slip on neck flange, socket welding flange and thread flange shall be no greater than 7°. 8.3.2 The taper neck slope of the weld neck flange shall be no greater than 45°, and it shall also be provided with straight section in slope of no greater than 7°; the sealing end complies with the requirements of Chapter 9 of this Standard. 8.3.3 The neck thickness S of the weld neck flange is generally no less than the nominal thickness of the steel pipe, of which shall be indicated by the user when ordering. S values listed in this Standard are only applicable to the occasions that users are not proposing specific requirements. 8.3.4 The butt welding ring wall thickness S of the butt welding ring loose flange is generally no less than the nominal thickness of the steel pipe, which shall be indicated by the user when ordering. Flanging thickness S1 of the butt welding ring shall be no less than the minimum wall thickness of the steel pipe (0.875S).

8.4 Pipe thread

8.4.1 The thread flange specified in this Standard is only applicable to outside diameter A series steel pipe. 8.4.2 The pipe thread adopted for the thread flange is classified into three occasions: 1 adopt 55°taper internal thread (Rc) specified in GB/T 7306; 2 adopt 55°cylinder internal thread (Rp) specified in GB/T 7306; 3 adopt 60°taper thread (NPT) specified in GB/T 12716. The user shall indicate the screw thread code when ordering; if it is not indicated, it is expressed as Rp pipe thread. 8.4.3 When adopting 55°pipe thread, outside diameter of the steel pipe for DN150 shall be 165.1mm. When adopting 60° taper thread, outside diameter of the steel pipe for DN65 flange shall be 73mm and outside diameter of the steel pipe for DN125 flange shall be 141.3mm. 8.4.4 The processing of inner bore pipe thread of the thread flange shall make the ends of the steel pipe approach each other but not exceed the flange seal contact face after screwing in. 9.1. […]

9.2 Slip on neck flange

9.2.2 Table 9.2.2-1 welding joint and groove dimension of the slip on neck flange connecting to the steel pipe shown in the scope of Table 9.2. […]

9.4 Weld neck flange

9.4.1 Welding joint and groove dimension of the weld neck flange connecting to the steel pipe shall comply with the requirements of Figure 9.4 (a). 9.4.2 When the straight section thickness of the weld neck flange is 1mm higher than the wall thickness of its butted steel pipe, the flange straight section shall be whittle down at the inside diameter, and the slope of the whittle down section shall be less than or equal to 1:3, see Figure 9.4 (b).

Note: When the flange is connecting to the ferrite steel pipe with nominal wall thickness of less than or equal to 4.8mm or

13.0.2 Marking illustration

Illustration 1: nominal dimension DN1200, nominal pressure PN6, raised face plate-type flat welding steel pipe flange of assorted metric system pipe, material is Q235A, it is marked as: HG/T 20592 flange PLl200 (B)-6 RF Q235A Illustration 2: nominal dimension DN300, nominal pressure PN25, male face slip on neck steel pipe flange of assorted English system pipe, material is 20 steel, it is marked as: HG/T 20592 flange SO 300-25 M 20 Illustration 3: nominal dimension DN100, nominal pressure PN100, female face weld neck steel pipe flange of assorted metric system pipe, material is 16Mn and steel pipe wall thickness is 8mm, it is marked as: HG/T 20592 flange WN100(B)-100 FM S=8mm 16Mn Illustration 4: nominal dimension DN150, nominal pressure PN160, ring joint face weld neck steel pipe flange of assorted English system pipe, material is 16Mn and steel pipe wall thickness is 10mm, it is marked as: HG/T 20592 flange WN150-160 RJ S=10mm 16Mn Illustration 5: nominal dimension DN500, nominal pressure PN16, tongue face integral type steel pipe flange, material is WCB and the roughness of seal contact surface is Ra0.8~1. […]

13.0.3 Procurement and delivery

4) Nominal dimension (DN); 5) Nominal pressure (PN); 6) Wall thickness of steel pipe connected to the weld neck flange and butt welding ring (slip-on flange); 7) Material grade 2 According to the requirements, and mutually agreed by both parties, the buyer may propose additional requirements. However, the specific requirements shall be explained in the procurement contract. For example: 1) Adopt material grades out of Table 4.0.1 of this Standard; 2) Flange forging levels is higher than the requirements of Article 4.0.3 of this Standard; 1 Standard No.: HG/T 20592 2 Flange type code (according to The requirements of Table 3.1.1) and taper pipe thread code of the thread flange (according to the requirements of Article 8.4.2 of this Standard); […]

A.3 Type and code

The type and code of the weld neck orifice flange are in accordance with those specified in Figure A.3-1 and Table A.3-1. The applicable nominal pressure and nominal dimension are in accordance with those specified in Table A.3-2.

A.4 Seal contact face

A.4. […]

A.5 Material

A.5.1 Materials for orifice flange complies with the requirements of Chapter 4 of this Standard, the bolting materials complies with the requirements of HG/T 20613 and the gasket complies with the requirements of HG/T 20606, HG/T 20607 and HG/T 20609~HG/T 20612. A.5.2 The pipe closer may adopt forging, rod or materials that with property of no less than that of the materials for orifice flange.

A.6 Maximum allowable working pressure

Maximum allowable working pressure of the flange complies with the requirements of Chapter 7 of this Standard.

A.7 Pressure tap

A.7.1 Each orifice flange shall be symmetrically opened with two DN15 (NPS 1/2) pressure taps, see Figure A.7.1, and each pressure tap shall be deployed with thread or socket pipe close. The pressure tap may also adopt other nominal dimensions, which shall be indicated by the user when ordering. A.7.2 The pressure tap may adopt socket weld joint or NPT pipe thread joint structure, and the physical dimension complies with the requirements of GB/T 14383.

A.7.3 The orifice flange adopting ring joint face may adopt pressure tap structure shown in Figure A.7.3 if necessary. A.7.4 The lifting bolt position is disposed in 90° with the pressure tap, see Figure A.7.1.

A.8 Dimension

A.8.1 The dimension of seal contact face of the flange complies with the requirements of Article 3.2.5 of this Standard. A.8.2 The coupling dimension and physical dimension of the flanges see the requirements of Figure A.8.2 and Table A.8.2-1~Table A.8.2-7.

A.9 Dimension tolerance

The dimension tolerance of the flange shall not only comply with the requirements of Chapter 10 of this Standard, but also the position h of the pressure tap shall be in accordance with the following requirements: 1 When the nominal dimension of flange is less than DN100, the dimension tolerance is±0. […]

A.11 Marking

A.11.2 Markings illustration: Illustration: raised face weld neck steel orifice flange with nominal dimension of DN200 and nominal pressure of PN63, the pressure tap adopts threaded connection, the flange material is 20 steel, and the steel pipe wall thickness grade is Sch40, it is marked as: HG/T 20592 orifice flange KWN-T 200-63 RF Sch40 20

B.1 Scope

B.1.1 This Appendix specifies the nominal dimension, nominal pressure, flange type, dimension, tolerance and technical requirement of steel jacket flange (PN designated). B.1.2 This Appendix is applicable to flange for full jacket pipe connection with nominal pressure grades of PN16, PN25 and PN40. B.1. […]