NB/T 47020-2012 English PDF (NBT47020-2012)

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NB/T 47020-2012: Type and specification for pressure vessel flanges
NB/T 47020-2012
INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Replacing NB/T 4700-2000
Type and Specification for Pressure Vessel Flanges
ISSUED ON. NOVEMBER 9, 2012
IMPLEMENTED ON. MARCH 1, 2013
Issued by. State Energy Administration
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Selection Principle and Applicable Corrosion Allowance in the Standard ... 5
4 Flange Classification, Material Matching, Working Temperature and Maximum Allowable Working
Pressure, Physical Dimension ... 5
5 Designation, Marking and Marking Sample... 6
6 Technical Specifications ... 15
Appendix A (Normative) Specification and Selection of Rolling Flange ... 18
Translation References and Original Chinese Documents ... 22
Foreword
Compared with JB/T 4700-2000, the main changes in this Standard are as follows.
-- Normative references have been updated;
-- Material designations have been updated correspondingly;
-- Flange materials Q235-A and 15MnVR is deleted;
-- Forging material 14Cr1Mo for welding neck flange have been added;
-- Dimension of welding neck flange has been further extended;
-- Gasket specification has been added, and to be consistent with the welding neck flange series
specification.
Appendix A in this Standard is normative.
This Standard was proposed by and under the jurisdiction of the National Technical Committee on
Boilers and Pressure Vessels of Standardization Administration of China (SAC/TC 262).
Drafting organizations of this Standard. Hefei General Machinery Research Institute, Sinopec
Engineering Incorporation, and Luoyang Petrochemical Engineering Corporation Ltd.
Drafting staff of this Standard. Yao Zuoquan, Feng Qingxiao, Guo Weimin, Qin Zongchuan, Xie Zhigang,
Hu Qingjun, Pan Jianhua, Sang Rubao, and Chen Chonggang.
The National Technical Committee on Boilers and Pressure Vessels of Standardization Administration of
China (SAC/TC 262) is in charge of the explanation of this Standard.
The previous editions of the standards replaced by this Standard are as follows.
-- JB 4700-1992;
-- JB/T 4700-2000.
Type and Specification for Pressure Vessel Flanges
1 Scope
This Standard specifies the classification and specification of pressure vessel flanges, the materials of
flanges, studs and nuts, and their matching with the gaskets; it also specifies the maximum allowable
working pressure, technical requirements and marking at all temperature levels.
This Standard is applicable to the flanges of carbon steel and low-alloy steel pressure vessels that the
nominal pressure is 0.25MPa~6.40MPa and working temperature is -70 ℃ ~450℃.
2 Normative References
The following documents are indispensable for the application of this Standard. For dated references,
only the dated edition is applicable to this document. For undated references, the latest editions of the
normative documents (including all the amendments) are applicable to this document.
GB 150 Pressure Vessels
GB/T 196 General Purpose Metric Screw Threads-Basic Dimensions
GB/T 197 General Purpose Metric Screw Threads-Tolerances
GB/T 539 Oil-resisting Asbestos-rubber Sheets
GB/T 699 Quality Carbon Structural Steels
GB/T 700 Carbon Structural Steels
GB 713 Steel Plates for Boiler and Pressure Vessels
GB/T 1801 Geometrical Product Specifications (GPS) - Limits and Fits - Selection of Tolerance
Zones and Fits
GB/T 1804 General Tolerances-Tolerances for Linear and Angular Dimensions without Individual
Tolerance Indications
GB/T 3077 Alloy Structure Steels
GB/T 3098.2 Mechanical Properties of Fasteners-Nuts-Coarse Thread
GB/T 3274 Hot-rolled Plates and Strips of Carbon Structural Steels and High Strength Low Alloy
Structural Steels
GB/T 3985 Asbestos-rubber Sheets
GB/T 5779.2 Fasters - Surface Discontinuities - Nuts
GB/T 16938 Fasteners-General Requirements for Blots, Screws, Studs and Nuts
GB 24511 Stainless Steel Plate, Sheet and Strip for Pressure Equipment
NB/T 47008 Carbon Steel and Alloy Steel Forgings for Pressure Equipment
breakdown list in the drawing.
For example. 16Mn (ring 06Cr19Ni10).
5.3.4 The material of the B-type flange nipple shall be the same with the flange material. If not the
same, its strength level shall not be less than that of the flange material and it shall have a good
weldability with the flange material, which shall be indicated in the breakdown column of the drawing
with the marking method same as 5.3.3. For example. Q245R (nipple Q345R). The nipple can be
lengthened. After lengthened, both the flange thickness δ and flange overall height H shall be indicated in
the flange marking.
6 Technical Specifications
6.1 The manufacturing, inspection and acceptance of flange shall not only meet the requirements of this
Standard, but also shall meet the requirements indicated in the drawing.
Technical specifications such as the material performance of long welding neck flange with
operating temperature equal to or less than -20℃ and its auxiliary studs, nuts, forging grade, low
temperature impact power index, manufacture and inspection shall meet the requirements of GB 150.
6.2 Material
6.2.1 The steel plates shall meet the requirements of GB 150, GB/T 3274 and GB 713.
6.2.2 Q235B steel plates shall not be used as pressure vessel flanges for highly or extremely toxic
media.
6.2.3 Q245R and Q345R steel plates with the thickness greater than 50 mm for flange shall be used
under normalized condition.
6.2.4 Butt welding is not allowed for long welding neck flanges but steel plate butt welding is allowed
for other flanges. Post-weld stress relief heat treatment shall be carried out for spliced flanges.
6.2.5 The inspection and acceptance of forgings shall be carried out as per Grade II of NB/T 47008 or
NB/T 47009 or as per the requirements of the drawing if there are special requirements.
6.2.6 Stainless steel material for lined ring shall comply with the requirements of GB 24511.
6.2.7 Rolled flanges shall meet the requirements of Appendix A (normative) and be selected according to
those specified in Table A.1 and A.2.
6.3 Machining
6.3.1 The outer diameter tolerance of the male surface and female surface of concave-convex sealing
surface flange, and the outer diameter tolerance of the tongue surface and groove surface of tongue and
groove seal contact surface flange shall meet the requirements of GB/T 1801. The hole shall be H12 and
the shaft shall be h12.
6.3.2 The permissible deviation of the pitch diameters of stud clearance holes and that of the chord
lengths of the two adjacent stud clearance holes shall be ± 0.6mm, and the permissible deviation of the
chord lengths of two stud clearance holes shall meet the requirements of Table 10.
Appendix A
(Normative)
Specification and Selection of Rolling Flange
A.1 Rolling flange shall comply with the requirements of the purchase contract as well as those of this
Appendix.
A.2 Section type and application scope shall meet the requirements in Table A.1 and Table A.2.
A.3 The types of steel commonly applied for flange rolling are 16Mn and No.20 Type. As for the
rolling of other types of steel, the agreement shall be made separately by the supplier and the demander.
A.4 The chemical component and mechanical property shall meet the requirements of NB/T 47008 or
NB/T 47009 Grade Ⅱ or purchase contract.
A.5 Sampling and inspection requirements of rolling flange
A.5.1 Flanges of the same furnace/pot number, size, specification and heat treatment p...