NB/T 47020-2012Type and Specification for Pressure Vessel Flanges (English PDF)

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.

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 °C ~450°C.

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 Designation, Marking and Marking Sample

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 delta 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°C and its auxiliary studs, nuts, forging grade, low temperature impact power index, manufacture and inspection shall meet the requirements of GB 150.

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.