NB/T 47015:2023 Welding specification for pressure vessels English Language
Welding specification for pressure vessels
1 Scope
This document specifies the basic welding requirements for pressure vessels made of steel, aluminum, titanium, copper, nickel, zirconium and composite metal.
This document is applicable to the pressure vessels manufactured by the welding processes such as oxyfuel gas welding, shielded metal arc welding, submerged arc welding, gas tungsten arc welding, gas metal arc welding, plasma arc welding, electron beam welding, electrogas welding, stud welding and strip surfacing.
This document is not applicable to the welding specification for gas cylinders.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 985.3 Recommended joint preparation for gas-shield arc welding on aluminium and its alloys
GB/T 3375 Welding terminology
GB/T 3670 Covered electrodes for manual metal arc welding of copper and copper alloys
GB/T 9460 Solid wires and rods for fusion welding of copper and copper alloys
GB/T 13814 Nickel and nickel alloy covered welding electrodes
GB/T 15620 Nickel and nickel alloy wires and rods
GB/T 30583 Specification for post weld heat treatment of pressure equipment
GB/T 39255 Gases and gas mixtures for welding and cutting processes
NB/T 47014 Welding procedure qualification for pressure equipments
NB/T 47016 Mechanical property tests of product welded test coupons for pressure equipments
NB/T 47018 (all parts) Specification of welding materials for pressure equipment
JB/T 3223 Welding consumables quality management procedures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 3375 and NB/T 47014 apply. In case of any inconsistency, those given in NB/T 47014 shall prevail.
4 General welding specification
4.1 General requirements
4.1.1 In addition to the requirements of this document, the welding of pressure vessels shall also meet the technical requirements of design documents.
4.1.2 In addition to the requirements of this document, the results proved effective through welding test research and practice may be applicable to the welding of pressure vessels after being recognized by relevant parties and included in the enterprise standards.
4.2 Welding materials
4.2.1 Welding materials include covered electrodes, welding wires, welding strips, fluxes, gases, electrodes and backings.
4.2.2 As for the pressure vessels, the covered electrodes, welding wires, welding strips and fluxes used for the welds of pressure elements, welds welded with pressure elements, and tack welds fused into permanent welds shall meet the requirements of NB/T 47018.
4.2.3 Gases for gas shielded arc welding of pressure vessels shall meet the requirements of GB/T 39255.
4.2.4 Selection principle of welding materials:
The mechanical properties of weld metal shall match those of base metal. The mechanical properties of weld metal welded according to reasonable welding procedure shall meet the requirements of NB/T 47016 and design documents. Where necessary, other properties of the weld metal shall not be inferior to the corresponding requirements of the base metal.
4.2.5 The manufacturing (installation) unit shall master the weldability of welding materials. The welding materials used for pressure vessels shall have the basis of welding test or practice.
4.2.6 The welding materials shall be provided with product quality certificates. The using unit shall conduct acceptance inspection or reinspection on the welding materials according to the requirements of quality management system as well as the relevant standards and design documents.
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4.3 Weld position
Weld positions are classified into four types: flat position, vertical position, horizontal position and overhead position. Their specified process and range are given in Annex A.
4.4 Welding procedure qualification and welders
When welding the following types of welds, the welding procedure adopted shall be qualified according to NB/T 47014, and the welders involved shall pass the examination according to TSG Z6002 Examination rules for welding operators of special equipment:
a) Welds of pressure elements;
b) Welds welded with pressure elements;
c) Tack welds of the above welds (for welding procedure), and tack welds fused into the above permanent welds (for welder);
d) Surfacing and repair welding on the surface of the base metal of pressure elements.
4.5 Preweld preparation
4.5.1 Site
4.5.1.1 The site of high-alloy steel pressure vessels shall be separated from that of other types of materials, where the ground shall be covered with anti-scratch pads.
4.5.1.2 Non-ferrous metal pressure vessels shall be manufactured in a dedicated site or space, and corresponding protection measures shall be taken.
4.5.2 Welding groove
4.5.2.1 The welding grooves shall be standard ones or self-designed based on the design drawings and procedure conditions. The groove type and size shall be determined with consideration of the following factors:
a) Welding process;
b) Type and thickness of base metal;
c) Using weld filler metal as little as possible;
d) Avoiding welding defects;
e) Reducing welding deformation and residual stress;
f) Being conducive to welding protection;
g) Convenience for welder to operate;
h) For groove of composite material, the dilution rate of weld metal in transition layer should be reduced; and it shall be easy to distinguish the interface between base layer and cladding layer when welding the corrosion-resistant layer.
4.5.2.2 See Annex B for the types and sizes of welding grooves for special materials.
4.5.3 Groove preparation
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 General welding specification
5 Welding specification for steel pressure vessels
6 Welding specification for aluminum pressure vessels
7 Welding specification for titanium pressure vessels
8 Welding specification for copper pressure vessels
9 Welding specification for nickel pressure vessels
10 Welding specification for zirconium pressure vessels
11 Welding specification for composite metal pressure vessels
12 Strip surfacing specification for corrosion-resistant layer
Annex A (Informative) Specified process and range for weld positions
Annex B (Informative) Types and sizes of welding grooves for special materials
Annex C (Informative) Recommended WPS form
Annex D (Informative) Recommended form of welding materials for common materials
