Detail of NB/T 47020-2012

Introduction of NB/T 47020-2012

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, the maximum allowable working pressure and technical requirements at tall temperaturelevels, as well as the marking. 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 Equipments NB/T 47008 Carbon Steel and Alloy Steel Forgings for Pressure Equipments NB/T 47009 Low-alloy Steel Forgings for Low Temperature Pressure Equipments NB/T 47021 A-type Socket-weld Flange NB/T 47022 B-type Socket-weld Flange NB/T 47023 Welding Neck Flange NB/T 47024 Nonmetallic Gaskets NB/T 47025 Spiral Wound Gaskets NB/T 47026 Double-jacketed Gaskets NB/T 47027 Fasteners for Pressure Vessel Flanges JB/T 4730 Nondestructive Testing of Pressure Equipments 3 Selection Principle and Applicable Corrosion Allowance in the Standard 3.1 The flanges specified in this Standard should be selected in priority as the pressure vessel flanges. The calculation in GB 150 may be omitted for the flanges selected according to this Standard. 3.2 The applicable corrosion allowance of B-type flange in this Standard shall not be greater than 2mm; where the corrosion allowance is greater than 2mm but not greater than 3mm, the nipple thickness shall be added by 2mm.The applicable corrosion allowance of welding neck flange shall not be greater than 3mm.

Contents of NB/T 47020-2012

Foreword i 1 Scope 2 Normative References 3 Selection Principle and Applicable Corrosion Allowance in the Standard 4 Flange Classification, Material Matching, Working Temperature and Maximum Allowable Working Pressure, Physical Dimension 5 Designation, Marking and Marking Sample 6 Technical Specifications Appendix A (Normative) Specification and Selection of Rolling Flange