HG 20624-1997 Technical Specifications for Steel Pipe Flanges (American System)
Some standard content:
Technical conditions for steel pipe flanges
(American system)
HG20624-97
1 Subject content Scope of application
This standard specifies the technical conditions for steel pipe flanges (American system). This standard applies to steel pipe flanges (including flange covers) specified in HG20615. 387
GB 150
GB 152. 1152. 4
GB 711
GB3274
GB3531
GB4237
GB6654
GB12229
GB12230
GB/T 14976
GB/T 16253
JJ34726
JB4727
JB4728
HG20537
HG20615
HG20625
Referenced Standards
《Steel Pressure Vessels》
《Through Holes and Countersunk Holes for Fasteners》
《Carbon Structural Steel》
《 "High-quality carbon structural steel hot-rolled thick steel plates and strips", "Carbon structural steel and low-alloy structural steel hot-rolled thick steel plates and strips", "Low-alloy steel plates for low-temperature pressure vessels", "Stainless steel hot-rolled steel plates"
"Pressure vessel steel plates"
"Technical conditions for carbon steel castings for general valves" "Technical conditions for austenitic steel castings for general valves" "Stainless steel seamless pipes for fluid transportation" "Carbon steel castings"
" Carbon steel and low alloy steel forgings for pressure vessels" "Carbon steel and low alloy steel forgings for pressure vessels" "Stainless steel forgings for pressure vessels"
"Austenitic stainless steel welded steel pipe"
Steel pipe flange types, parameters (American system) \ "Steel pipe flange pressure-temperature grade (American system) 3 Materials
3.0.1 The materials for steel pipe flanges shall comply with the provisions of Table 3.0.1. Their chemical composition, mechanical properties and other technical requirements shall comply with the provisions of the relevant standards listed in 3.0.1.
3.0.2 The nominal pressure PV and working temperature range of flange materials shall comply with the provisions of Table 3.0.2. 389
D!ING[300
0w9199[9z
LON8EJ0
INUWGO
(99 0)
(002 H9)
(LGin81)
QTINGTOOG
OWs *0 -+5t1*
wl-/l&
Class Jingyin
1i.3116Mn
1Cr-0.5Mo
1 21/40:-1Mo
5Cr- 0. 5Mo
Table 3.0.Z Nominal pressure and working temperature of pipe cover materials Steel No. (standard No.)
Q33J1(GB 3271)
70(GB 711)
2GR(GR 665))
20(TB1726)
16MnR(GB 6651)
16MnLR(GB 3331)
16Mn(JR 4726)
16MnD(JB1727)||tt|( 3531)15CrMoR(GB$654)
15CrMoJB 4726)
12Cr2MoIR(GR150.GBG954)
12Cr2Mo1(J134726)
1Cr5Mo(JB 4726)
0Cr18N18(GB4237, JB472)
CCr17Ni12Mo2(GE1237, JB4725）(MCr19N7:C(GB 1237.JB 4728)
OCCr17Ni14M2(GB 1237.JB 4728)9Cr18Ni10Ti(GB4237.JB4728)
GGh1RN9TD)
Nominal repulsion PN.MPa
.42. (
Working temperature, ℃
0~.—350
5~-350
≥—20~—425(475)
>--20-~ +425 (275)
>-20~+425(173)
:590
—20-~ +5751590)
2-20-~+699
-- 195~-+7c0(800)
-196-- 1 730(800)
136~+425
156~+125
196~—700(800)
, the overall method of registered casting materials "its pressure range is in accordance with the provisions of relevant standards (such as valve, machine standards), so the table lists the suitable range of 1.1, 1.2 materials. The steel pipe material is stainless steel, and the working pressure and temperature are in accordance with the provisions of relevant steel pipe standards. Because the code is used for many purposes, the upper temperature limit is not recommended: the grade and technical requirements of forgings (including forgings) shall comply with the corresponding requirements of JB4726~-4728. 3.0.3
Low carbon steel (category number 1.0) and austenitic stainless steel forgings with a nominal pressure of PN2.0MPa are allowed to use grade 1 forgings. 1
2Except as provided in the above and below paragraphs, forgings with a nominal pressure PV≤5.0MPa shall comply with the requirements of grade 1 or grade Ⅱ or above forgings.
3For those who meet any of the following conditions, they shall comply with the requirements of composite grade forgings: (I) Flange forgings with a nominal pressure of PN11.0MPa; (2) Chrome clamp forgings with a nominal pressure of PN25.0MPa; (3) Nominal pressure P V5.MPa ear working temperature -20 (ferritic steel forgings. 3.0.4 Neck butt welding, flat neck, socket welding, threaded and loose flanges should be made of forging or forging and rolling. 3.0.5 The outer neck slope of the neck of the flat neck, socket welding flange, threaded flange and loose flange should not be greater than -7°391
4 Dimension tolerance
4.0.1 The dimension tolerance of the flange shall be in accordance with the provisions of Table 4.0.1-1~3. 4.0.2 The machining surface roughness of the flange seal shall be selected according to the provisions of Table 4.0.2-1 and indicated when ordering. When the surface roughness requirement of the sealing surface is not indicated when ordering, it shall be in accordance with the provisions of Table 4.0.2-2. 4.0.3 The dimension tolerance of the ring connection surface from the cover According to the provisions of Table 4..3. The minimum hardness value of the ring groove should be 30HB higher than the maximum hardness value of the metal gasket used. Table 4..-1 Dimensional tolerance items of DN600mm flange Flange thickness C Standard height H Welding end of butt-welded flange External diameter A Flange flange diameter d (except for ring connection) Bolt hole center diameter K Distance between adjacent bolts Bolt hole diameter 1 Degree of parallelism between bolt hole center circle and machining surface Non-parallelism between sealing surface and explosive bearing surface Standard type |Double welding flange
Inner diameter of bottle welding flange
Inner diameter of flat neck method
Inner diameter of loose sleeve flange
Inner diameter of socket of folding welding flange
All types of double-sided processing
Type method"
(including Wei dead)
Neck flange
Align flange
All types
All types
All types
All types
All types
Size range
DN≤250
DN300--450
SDN123
The height of the raised platform with the enclosed surface is 1.6
The height of the raised platform with the sealing surface is 6.4
Sakata deviation
Outer diameter of butt welding ring end A
Inner diameter of butt welding ring
Length of butt welding ring h
Outer diameter of butt welding ring sealing surface
Corner radius R:
Thickness of butt welding ring flange T
Outer diameter D
Inner diameter of flange B
Thickness of flange C
Outer diameter of sealing flange
Height of flange H
Dimension of flange part N
Outer diameter of flange welding end A
Diameter of center of screw hole K
Spacing between adjacent bolt holes
Diameter of bolt hole L
Table 4.0. [一2 Loose flange with welding ring size limited deviation size range
DN1565
IN80~-100
DN125~200
DN15-65
JN80~200
DN15~200
DN15~200
DN15~80
All nominal diameters
Limit code
一12.5% steel pipe nominal stop
Table 4.0.1-3 IN,>600mm Limit deviation of large diameter flange size
Flange inner diameter to the center circle of the screw inspection hole
Non-metallic gasket
Flexible graphite composite gasket
PTFE coated gasket
Tooth combination
Spiral wound gasket
Gold screen coated gasket
Gold ring gasket
Sealing surface type
Raised surface. Concave and convex surface
Gasket type
Table 4. 0. 2—1
Stainless steel
Carbon steel, chrome steel
Stainless steel
Table 4. Core 2-2
Sealing surface code
RF, MFM
Sinus surface (processing dense waterline,
only for soft seal>
Full half surface
Rod groove surface
Ring connection surface
Surface roughness of sealing surface
Surface roughness of cover
Ra6.3～12.5(processing waterline）
Ra6.3～12.5(with T waterline)
Ra6.3~12.5(processing waterline）
Ra3. 2~~6. 3
Ra3. 2~6. 3
Ra1. 6~3. 2
Ra0. 8~-1. 6
Ra0. 8～1. 6
Ra0. 4~0. 8
When no note is given, the roughness of the sealing surface Raum
Degree 4.0.3 Sealing surface dimension of the ring connection surface
Ring groove depth E
Ring groove top density F
Ring center circle diameter
Ring groove angle 23°
Ring mask fillet Rrar
Seal surface outer diameter d
Dense groove waterline size.mm
Waterline pitch
Limit deviation
Add T tool angle
Bolt bearing surface processing of flange
5.0.1 The bolt bearing surface of the flange shall be machined or drilled (fisheye hole). The hole size shall comply with the provisions of G152.4. The non-parallelism between the bearing surface and the sealing surface shall comply with the provisions of Table 4.0.1-1. 5.0.2 After the bearing surface of the flange is machined or bored, the thickness of the flange shall comply with the limit deviation requirements of Table 4.0.1-1 or Table 4.0.13.
6 Hydrostatic test
In principle, the pipe method does not conduct hydrostatic test on a single flange. After the flange is installed on the pipeline or equipment, its hydrostatic test pressure shall not be greater than 1.5 times the maximum non-impact working pressure at 20C specified in HG20625. 396
7.0.1: Appearance inspection
7. Inspection and acceptance
! The forging surface shall be smooth and shall not have defects such as forging marks and cracks. 2 The sand and scale on the casting surface should be cleaned up, and defects that affect the performance of the casting (such as cracks, slag from the box hole) are not allowed to exist.
3 The machined surface shall not have burrs, harmful scratches and other defects that reduce the strength and connection reliability of the flange. 4 The sealing surface of the ring connection flange shall be checked one by one, and the two sides shall not have surface defects such as cracks, scratches and scratches caused by machining.
The flange material composition shall comply with the provisions of the relevant standards and it shall have a factory inspection certificate. 7.0.2
The processing quality of the flange shall comply with the service regulations of this standard. 7.0.3
7.0.4 After the flange is processed, anti-rust oil shall be applied to its sealing surface to prevent scratches and impact. 397
8 Packaging and steel stamping marks
The flanges shall be packaged separately according to specifications and materials. The product inspection certificate shall be attached upon delivery. The outer web surface of each flange (including flange cover) shall be stamped with the items specified in 8.0.2. 8.0.2 The stamped marking of flanges (including flange covers) shall include at least the following contents; (1) Standard number
All types of pipe flanges shall be uniformly marked with HG20515: (2) Flange type code shall be in accordance with the provisions of Table 8.0.2-1 8.0.2 Flange type code
Flange type
Flat welding method with neck
Butt welding flange with neck
Integral flange
Socket welding flange
Threaded method
Butt welding ring Loose flange
Flange type
Flange type code
When the threaded flange adopts the taper pipe thread specified in GB7306, it is marked as \Th (Rc)" When the threaded flange adopts the taper pipe thread specified in GB/T12716, it is marked as *Th (NPT) (3) Flange nominal diameter DNmm
(4) Flange nominal pressure PN.MPa
(5) Sealing surface type code, according to the provisions of Table 8.0.2-2; Set 8. Reference. 2 — 2
Sealing surface type
Raised surface (water line)
Dense pair mark code
(6)Steel pipe wall thickness (same table number) to be provided by the user: Raised surface
Full plane
Ring connection surface
Neck welding flange, welding ring loose flange and PN11.0MPa (Class600) socket welding flange should be marked with steel pipe thickness:
(7)Material code, according to Table 8.0.2-3. Material code
Table 8.0.2 — 3
16MaD,16MnDR
o0Cr19Ni10
09Mn2VR
15CrMo.15CrMoR
OCr18Ni10Ti(1Cri8Ni9Ti)
09MnNiD
12Cr2Mo1R.12Cr2Mo1
OC r17Ni12Mo2
16Mn.16MnR
GCrIBNi9
00C-17Ni14Mo2>600mm Large diameter flange size limit deviation
Flange inner diameter to the center circle of the screw inspection hole Flange inner diameter to the center circle of the sealing surface end center limit deviation
Non-metallic gasket
Flexible graphite composite gasket
PTFE coated gasket
Tooth combination
Spiral wound gasket
Gold screen coated gasket
Gold ring gasket
Sealing surface type
Raised surface. Concave and convex surface
Gasket type
Table 4. 0. 2—1
Stainless steel
Carbon steel, chrome steel
Stainless steel
Table 4. Core 2-2
Sealing surface code
RF, MFM
Sinus surface (processing dense waterline,
only for soft seal>
Full half surface
Rod groove surface
Ring connection surface
Surface roughness of sealing surface
Surface roughness of cover
Ra6.3～12.5(processing waterline）
Ra6.3～12.5(with T waterline)
Ra6.3~12.5(processing waterline）
Ra3. 2~~6. 3
Ra3. 2~6. 3
Ra1. 6~3. 2
Ra0. 8~-1. 6
Ra0. 8～1. 6
Ra0. 4~0. 8
Roughness of sealing surface when no note is given Raum
Degree 4.0.3 Sealing surface dimension of ring connection surface
Ring groove depth E
Ring groove top density F
Ring center circle diameter
Ring groove angle 23°
Ring mask fillet Rrar
Outer diameter of sealing surface d
Dense groove waterline size.mm
Waterline pitch
Limit deviation
Add T tool angle
Machining of bolt bearing surface of flange
5.0.1 Bolt bearing surface of flange shall be machined or drilled with holes (fisheye holes). The hole size shall comply with the provisions of G152.4. The non-parallelism between bearing surface and sealing surface shall comply with the provisions of Table 4.0.1-1. 5.0.2 The bolt bearing surface of flange shall be machined or drilled with holes (fisheye holes). The bolt bearing surface of flange shall be machined or drilled with holes (fisheye holes). The bolt bearing surface size shall comply with the provisions of G152.4. The non-parallelism between bearing surface and sealing surface shall comply with the provisions of Table 4.0.1-1. After inserting the hole, the thickness of the flange should be guaranteed to meet the limit deviation requirements of Table 4.0.1-1 or Table 4.0.13.
6 Hydrostatic test
In principle, the hydraulic test of a single flange is not carried out for pipe production. After the flange is installed on the pipeline or equipment, its hydraulic test pressure should not be greater than 1.5 times the maximum non-impact working pressure at 20C specified in HG20625. 396
7.0.1: Appearance inspection
7. Inspection and acceptance
! The forging surface should be smooth and free of defects such as forging marks and cracks. 2 The sand and oxide scale on the casting surface should be cleaned up, and defects that affect the performance of the casting (such as cracks, slag from the box hole) are not allowed to exist
3 The machined surface shall not have burrs, harmful scratches and other defects that reduce the strength and connection reliability of the flange. 4. The sealing surface of the flange should be checked one by one. The two sides should not have surface defects such as cracks, scratches and scratches caused by organic processing.
The material composition of the flange should meet the requirements of the relevant standards and it should have a factory inspection certificate. 7.0.2
The processing quality of the flange should meet the requirements of this standard. 7.0.3
7.0.4 After the flange is processed, anti-rust oil should be applied to its sealing surface to prevent scratches and impact. 397
8 Packaging and steel stamping
The flanges should be packed separately according to specifications and materials. The product inspection certificate should be attached when delivering. The outer net column surface of each flange (including the flange cover) should be marked with steel stamps as specified in 8.0.2. 8.0.2 The steel stamp mark of flange (including flange cover) shall include at least the following contents; (1) Standard number
All types of pipe flanges shall be uniformly marked with HG20515: (2) Flange type code shall be in accordance with the provisions of Table 8.0.2-1. 8.0.2 Flange type code
Flange type
Neck flat welding method
Neck butt welding flange
Integral flange
Socket welding flange
Threaded method
Butt welding ring Loose flange
Flange type
Flange type code
When the threaded flange adopts the taper pipe thread specified in GB7306, it is marked as \Th (Rc)" When the threaded flange adopts the taper pipe thread specified in GB/T12716, it is marked as *Th (NPT) (3) Flange nominal diameter DNmm
(4) Flange nominal pressure PN.MPa
(5) Sealing surface type code, according to the provisions of Table 8.0.2-2; Set 8. Reference. 2 — 2
Sealing surface type
Raised surface (water line)
Dense pair mark code
(6)Steel pipe wall thickness (same table number) to be provided by the user: Raised surface
Full plane
Ring connection surface
Neck welding flange, welding ring loose flange and PN11.0MPa (Class600) socket welding flange should be marked with steel pipe thickness:
(7)Material code, according to Table 8.0.2-3. Material code
Table 8.0.2 — 3
16MaD,16MnDR
o0Cr19Ni10
09Mn2VR
15CrMo.15CrMoR
OCr18Ni10Ti(1Cri8Ni9Ti)
09MnNiD
12Cr2Mo1R.12Cr2Mo1
OC r17Ni12Mo2
16Mn.16MnR
GCrIBNi9
00C-17Ni14Mo2>600mm Large diameter flange size limit deviation
Flange inner diameter to the center circle of the screw inspection hole Flange inner diameter to the center circle of the sealing surface end center limit deviation
Non-metallic gasket
Flexible graphite composite gasket
PTFE coated gasket
Tooth combination
Spiral wound gasket
Gold screen coated gasket
Gold ring gasket
Sealing surface type
Raised surface. Concave and convex surface
Gasket type
Table 4. 0. 2—1
Stainless steel
Carbon steel, chrome steel
Stainless steel
Table 4. Core 2-2
Sealing surface code
RF, MFM
Sinus surface (processing dense waterline,
only for soft seal>
Full half surface
Rod groove surface
Ring connection surface
Surface roughness of sealing surface
Surface roughness of cover
Ra6.3～12.5(processing waterline）
Ra6.3～12.5(with T waterline)
Ra6.3~12.5(processing waterline）
Ra3. 2~~6. 3
Ra3. 2~6. 3
Ra1. 6~3. 2
Ra0. 8~-1. 6
Ra0. 8～1. 6
Ra0. 4~0. 8
Roughness of sealing surface when no note is given Raum
Degree 4.0.3 Sealing surface dimension of ring connection surface
Ring groove depth E
Ring groove top density F
Ring center circle diameter
Ring groove angle 23°
Ring mask fillet Rrar
Sealing surface outer diameter d
Dense groove waterline size.mm
Waterline pitchbZxz.net
Limit deviation
Add T tool angle
Machining of bolt bearing surface of flange
5.0.1 Bolt bearing surface of flange shall be machined or drilled with holes (fisheye holes). The hole size shall comply with the provisions of G152.4. The non-parallelism between bearing surface and sealing surface shall comply with the provisions of Table 4.0.1-1. 5.0.2 The bolt bearing surface of flange shall be machined or drilled with holes (fisheye holes). The bolt bearing surface of flange shall be machined or drilled with holes (fisheye holes). The bolt bearing surface size shall comply with the provisions of G152.4. The non-parallelism between bearing surface and sealing surface shall comply with the provisions of Table 4.0.1-1. After inserting the hole, the thickness of the flange should be guaranteed to meet the limit deviation requirements of Table 4.0.1-1 or Table 4.0.13.
6 Hydrostatic test
In principle, the hydraulic test of a single flange is not carried out for pipe production. After the flange is installed on the pipeline or equipment, its hydraulic test pressure should not be greater than 1.5 times the maximum non-impact working pressure at 20C specified in HG20625. 396
7.0.1: Appearance inspection
7. Inspection and acceptance
! The forging surface should be smooth and free of defects such as forging marks and cracks. 2 The sand and oxide scale on the casting surface should be cleaned up, and defects that affect the performance of the casting (such as cracks, slag from the box hole) are not allowed to exist
3 The machined surface shall not have burrs, harmful scratches and other defects that reduce the strength and connection reliability of the flange. 4. The sealing surface of the flange should be checked one by one. The two sides should not have surface defects such as cracks, scratches and scratches caused by organic processing.
The material composition of the flange should meet the requirements of the relevant standards and it should have a factory inspection certificate. 7.0.2
The processing quality of the flange should meet the requirements of this standard. 7.0.3
7.0.4 After the flange is processed, anti-rust oil should be applied to its sealing surface to prevent scratches and impact. 397
8 Packaging and steel stamping
The flanges should be packed separately according to specifications and materials. The product inspection certificate should be attached when delivering. The outer net column surface of each flange (including the flange cover) should be marked with steel stamps as specified in 8.0.2. 8.0.2 The steel stamp mark of flange (including flange cover) shall include at least the following contents; (1) Standard number
All types of pipe flanges shall be uniformly marked with HG20515: (2) Flange type code shall be in accordance with the provisions of Table 8.0.2-1. 8.0.2 Flange type code
Flange type
Neck flat welding method
Neck butt welding flange
Integral flange
Socket welding flange
Threaded method
Butt welding ring Loose flange
Flange type
Flange type code
When the threaded flange adopts the taper pipe thread specified in GB7306, it is marked as \Th (Rc)" When the threaded flange adopts the taper pipe thread specified in GB/T12716, it is marked as *Th (NPT) (3) Flange nominal diameter DNmm
(4) Flange nominal pressure PN.MPa
(5) Sealing surface type code, according to the provisions of Table 8.0.2-2; Set 8. Reference. 2 — 2
Sealing surface type
Raised surface (water line)
Dense pair mark code
(6)Steel pipe wall thickness (same table number) to be provided by the user: Raised surface
Full plane
Ring connection surface
Neck welding flange, welding ring loose flange and PN11.0MPa (Class600) socket welding flange should be marked with steel pipe thickness:
(7)Material code, according to Table 8.0.2-3. Material code
Table 8.0.2 — 3
16MaD,16MnDR
o0Cr19Ni10
09Mn2VR
15CrMo.15CrMoR
OCr18Ni10Ti(1Cri8Ni9Ti)
09MnNiD
12Cr2Mo1R.12Cr2Mo1
OC r17Ni12Mo2
16Mn.16MnR
GCrIBNi9
00C-17Ni14Mo2Inspection and acceptance
! The forging surface should be smooth and free of defects such as forging marks and cracks. 2 The sand and scale on the casting surface should be cleaned up, and defects that affect the performance of the casting (such as cracks, slag from the box hole) are not allowed to exist
3 The machined surface shall not have burrs, harmful scratches and other defects that reduce the strength and connection reliability of the flange. 4 The sealing surface of the ring connection flange shall be inspected one by one, and the two sides shall not have surface defects such as cracks, scratches and scratches caused by machining
The flange material composition shall comply with the provisions of the relevant standards and it shall have a factory inspection certificate. 7.0.2
The processing quality of the flange shall comply with the service regulations of this standard. 7.0.3
7.0.4 After the flange is processed, anti-rust oil shall be applied to its sealing surface to prevent scratches and impact 397
8 Packaging and steel stamping marks
The flanges shall be packaged separately according to specifications and materials. The product inspection certificate shall be attached upon delivery. The outer web surface of each flange (including flange 8. . 1
cover) shall be stamped with the items specified in 8.0.2. 8.0.2 The stamped marking of flanges (including flange covers) shall include at least the following contents; (1) Standard number
All types of pipe flanges shall be uniformly marked with HG20515: (2) Flange type code shall be in accordance with the provisions of Table 8.0.2-1 8.0.2 Flange type code
Flange type
Flat welding method with neck
Butt welding flange with neck
Integral flange
Socket welding flange
Threaded method
Butt welding ring Loose flange
Flange type
Flange type code
When the threaded flange adopts the taper pipe thread specified in GB7306, it is marked as \Th (Rc)" When the threaded flange adopts the taper pipe thread specified in GB/T12716, it is marked as *Th (NPT) (3) Flange nominal diameter DNmm
(4) Flange nominal pressure PN.MPa
(5) Sealing surface type code, according to the provisions of Table 8.0.2-2; Set 8. Reference. 2 — 2
Sealing surface type
Raised surface (water line)
Dense pair mark code
(6)Steel pipe wall thickness (same table number) to be provided by the user: Raised surface
Full plane
Ring connection surface
Neck welding flange, welding ring loose flange and PN11.0MPa (Class600) socket welding flange should be marked with steel pipe thickness:
(7)Material code, according to Table 8.0.2-3. Material code
Table 8.0.2 — 3
16MaD,16MnDR
o0Cr19Ni10
09Mn2VR
15CrMo.15CrMoR
OCr18Ni10Ti(1Cri8Ni9Ti)
09MnNiD
12Cr2Mo1R.12Cr2Mo1
OC r17Ni12Mo2
16Mn.16MnR
GCrIBNi9
00C-17Ni14Mo2Inspection and acceptance
! The forging surface should be smooth and free of defects such as forging marks and cracks. 2 The sand and scale on the casting surface should be cleaned up, and defects that affect the performance of the casting (such as cracks, slag from the box hole) are not allowed to exist
3 The machined surface shall not have burrs, harmful scratches and other defects that reduce the strength and connection reliability of the flange. 4 The sealing surface of the ring connection flange shall be inspected one by one, and the two sides shall not have surface defects such as cracks, scratches and scratches caused by machining
The flange material composition shall comply with the provisions of the relevant standards and it shall have a factory inspection certificate. 7.0.2
The processing quality of the flange shall comply with the service regulations of this standard. 7.0.3
7.0.4 After the flange is processed, anti-rust oil shall be applied to its sealing surface to prevent scratches and impact 397
8 Packaging and steel stamping marks
The flanges shall be packaged separately according to specifications and materials. The product inspection certificate shall be attached upon delivery. The outer web surface of each flange (including flange 8. . 1
cover) shall be stamped with the items specified in 8.0.2. 8.0.2 The stamped marking of flanges (including flange covers) shall include at least the following contents; (1) Standard number
All types of pipe flanges shall be uniformly marked with HG20515: (2) Flange type code shall be in accordance with the provisions of Table 8.0.2-1 8.0.2 Flange type code
Flange type
Flat welding method with neck
Butt welding flange with neck
Integral flange
Socket welding flange
Threaded method
Butt welding ring Loose flange
Flange type
Flange type code
When the threaded flange adopts the taper pipe thread specified in GB7306, it is marked as \Th (Rc)" When the threaded flange adopts the taper pipe thread specified in GB/T12716, it is marked as *Th (NPT) (3) Flange nominal diameter DNmm
(4) Flange nominal pressure PN.MPa
(5) Sealing surface type code, according to the provisions of Table 8.0.2-2; Set 8. Reference. 2 — 2
Sealing surface type
Raised surface (water line)
Dense pair mark code
(6)Steel pipe wall thickness (same table number) to be provided by the user: Raised surface
Full plane
Ring connection surface
Neck welding flange, welding ring loose flange and PN11.0MPa (Class600) socket welding flange should be marked with steel pipe thickness:
(7)Material code, according to Table 8.0.2-3. Material code
Table 8.0.2 — 3
16MaD,16MnDR
o0Cr19Ni10
09Mn2VR
15CrMo.15CrMoR
OCr18Ni10Ti(1Cri8Ni9Ti)
09MnNiD
12Cr2Mo1R.12Cr2Mo1
OC r17Ni12Mo2
16Mn.16MnR
GCrIBNi9
00C-17Ni14Mo2
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