1 Scope
This standard specifies the technical requirements for the welding work of boilers, pressure vessels, pressure pipelines, steel structures and non-pressure parts welding on pressure parts and for the welding repair work of main and auxiliary parts for design, installation, maintenance, reconstruction project and auxiliary processing and manufacturing of thermal power plant.
This standard is applicable to shielded metal arc welding (SMAW), tungsten inert gas welding (TIG), consumable electrode (solid-core and flux-cored wire) gas metal arc welding (GMAW, FCAW), oxyfuel gas welding (OFW), submerged-arc welding (SAW), etc.
This standard is also applicable to the welding of non-pressure structures, leakproof and general support structures.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated normative references, only the dated editions are applicable to this document. For undated references, the latest edition (including any amendments) applies.
GB 713 "Steel Plates for Boiler and Pressure Vessels"
GB/T 985.1 "Recommended Joint Preparation for Gas Welding, Manual Metal Arc Welding, Gas-shield Arc Welding and Beam Welding"
GB/T 985.2 "Recommended Joint Preparation for Submerged Arc Welding"
GB/T 3323 "Radiographic Examination of Fusion Welded Joints in Metallic Materials"
GB/T 4842 "Argon"
GB/T 5293 "Carbon Steel Electrodes and Fluxs for Submerged Arc Welding"
GB 5310 "Seamless Steel Tubes and Pipes for High Pressure Boiler"
GB 6819 "Dissolved Acetylene"
GB/T 11345 "Method for Manual Ultrasonic Testing and Classification of Testing Results for Ferritic Steel Welds"GB/T 12470 "Low-alloy Steel Electrodes and Fluxs for Submerged Arc Welding"
GB/T 17394 "Metallic Materials-Leeb Hardness Test"
DL/T 438 "Technical Supervision Codes for Metal in Thermal Power Plants"
DL/T 675 "Examination Code for Qualification of Non-destructive Testing Personnel of Electric Power Industry"
DL/T 678 "General Welding Procedure Specification for Structural Steel of Power Station"
DL/T 679 "Code for Welder Technical Qualification"
DL/T 734 "Technical Guide of Welding Repair for Boiler Drum in Fossil-Fired Power Plants"
DL/T 752 "The Code of the Welding on Dissimilar Steel for Power Plant"
DL/T 753 "Technical Guide for Repair Welding of Cast Steel Parts in Steam Turbine"
DL/T 754 "Code of the Welding Technique for Aluminium Bus for Power Plant"
DL/T 819 "The Code for the Welding Heat Treatment for Power Plant"
DL/T 820 "The Code of Ultrasonic Inspection Section for Butt Welds of Pipes"
DL/T 821 "The Code of Radiographic Examination of Butt Welded-Joints of Pressure Steels Pipes and Tubes"
DL/T 868 "The Code of Welding Procedure Qualification"
DL/T 884 "Power Plant Metallography Inspection and Assessment Guideline"
DL/T 905 "Technical Guide for Repair Welding of Turbine Blades"
DL/T 931 "The Rule of Physico-chemical Personnel Qualification in Electric Power Industry"
DL/T 991 "Spectral Analysis Guideline of Metal for Electrical Power Equipment"
DL/T 1097 "The Code of Welding for Tube-plate of Condenser of Power Plant"
DL/T 5210.7 "Code for Construction Quality Acceptance and Evaluation of Electric Power Construct-Part 7: Welding"
HG/T 2537 "Carbon Dioxide for Welding Use"
HG/T 3728 "Mixed Gas for Welding Argon-Carbon Dioxide"
JB/T 3223 "Rules of Quality Management of Welding Materials"
JB/T 4730.1~JB/T 4730.6 "Nondestructive Testing of Pressure Equipments"
SJ/T 10743 "Ceriated Tungsten Electrodes for Inert Gas Arc Welding and Plasma Welding and Cutting"
3 General Requirements
3.1 General
3.1.1 The welding work for steel structure, aluminium bus and condenser tube plate for power station shall comply with the requirements of DL/T 678, DL/T 754 and DL/T 1097 respectively.
3.1.2 The welding engineering shall be subjected to welding procedure qualification and welding procedure (operation) instruction preparation according to DL/T 868, and to welding construction measures document preparation if necessary.
3.1.3 The quality inspection for welded joints shall be carried out according to the operating conditions of the parts and the classification of the quality requirements.
3.1.4 Such work as quality inspection for welded joints and welder examination shall be carried out according to the relevant regulations respectively.
3.1.5 The quality acceptance and qualification work of welding engineering shall be carried out in accordance with DL/T 5210.7.
3.1.6 The welding and repair on important parts shall be carried out in accordance with special regulations, specifications and technical guidelines.
3.1.7 The welding work shall comply with the national and profession safety and environmental protection provisions as well as other special provisions.
3.2 Company and welder
3.2.1 Qualifications to be possessed of by construction, supervision, overhaul and relevant organizations who undertake welding and inspection of thermal power plant
a) Company qualification approved by the nation and appropriate to undertaken engineering, and corresponding quality assurance system shall be provided.
b) The company's quality system shall make definite provisions for welding engineering management, and shall be capable of effectively operating in welding engineering construction and its supervision process to ensure the welding engineering quality.
c) Professional welding principal shall be designated to be responsible for technical, quality and safety work of this profession.
d) Welding construction, inspection equipment and human resources appropriate to engineering scale shall be provided.
Foreword I
Introduction II
1 Scope
2 Normative References
3 General Requirements
4 Groove Preparation and Assembly Requirements
5 Welding Procedure
6 Quality Inspection
7 Quality Criteria
8 Welding Recovery
9 Technical Documents for Welding
Appendix A (Informative) Chemical Composition and Mechanical Property of Common Steels of Power Plant
Appendix B (Informative) Zoom Table of Electrodes (Welding Wires) for Welding Dissimilar Steels and Post-weld Heat Treatment Temperature
Appendix C (Informative) Chemical Composition and Mechanical Property at Normal Temperature for Common Electrode Deposited Metal
Appendix D (Informative) Chemical Composition of Common Welding Wires
Appendix E (Normative) Special Technical Requirements for Welding of Austenitic Stainless Steel and Nickel-based Alloy
Appendix F (Normative) Specific Requirements for Welding Technique of 9%~12%Cr Martensite Heat Resistant Steel
Appendix G (Informative) First Pass Yield of Welded Joints for Non-destructive Testing
