This code specifies the scope of parts with metal supervision in fossil-fuel power plant as well as the items, contents and corresponding criteria of inspection and supervision.
This code is applicable to the supervision on the following metal parts:
a) The high-temperature pressure parts with working temperature larger than or equal to 400℃ (including main steam pipeline, high-temperature reheat pipeline, superheater tube, reheater tube, header, valve casing and tee joint) as well as the small pipes connected the pipelines and headers.
b) The steam lead pipe and connection pipe with working temperature larger than or equal to 400℃.
c) The steam drum with working pressure larger than or equal to 3.82MPa as well as the steam separator and water storage tank of monotube boiler.
d) The pressure steam and water pipelines and parts with working pressure larger than or equal to 5.88MPa (including cold-wall tube, evaporator, economizer tube, header and main feed water pipeline).
e) The shaft, impeller, blades, lashing wire and bearing bush of steam turbine as well as the shaft, retaining ring and fan blades of generator.
f) Bolts with working temperature greater than or equal to 400℃.
g) Steam cylinder, steam chamber, main throttle valve, throttle, nozzle, partition panel and diaphragm sleeve with working temperature larger than or equal to 400℃.
h) Low-temperature reheat pipeline with longitudinal seams of 300MW and above units
2 Normative References
The following documents contain provisions which, through reference in this text, constitute provisions of this code. For dated reference, subsequent amendments (excluding amending error in the text) to, or revisions of, any of these publications do not be applied. However, the parties whose enter into agreement according to these specifications are encouraged to research whether the latest editions of these references are applied or not. For undated references, the latest edition of the normative document is applicable to this code.
GB 713—2008 Steel Plates for Boiler and Pressure Vessels
GB 5310—2008 Seamless Steel Tubes and Pipes for High Pressure Boiler
GB/T 9222—2008 Strength Calculation of Pressure Parts for Watertube Boilers
GB/T 19624—2004 Safety Assessment for In-Service Pressure Vessels Containing Defects
GB/T 20410—2006 Steels for Turbine Bolts at High Temperature
DL/T 439—2006 The Technical Guide for High-Temperature Bolt of Fossil-Fired Power Plant
DL/T 440—2004 The Code of Inspection and Evaluation for Existing Boiler Drum in Fossil-Fuel Power Plants
DL/T 441—2004 Supervision Code for Creep Strain of Steam Pipe in High Temperature and High Pressure in Fossil Fuel Power Plant
DL 473—1992 Technical Specification of Large Diameter Tee Forgings
DL/T 505 The Guide of Ultrasonic Inspection for Welding of Steam Turbine Shaft
DL/T 515—2004 Pipe Bends for Power Station
DL/T 531—1994 Technical Specification of High Temperature High Pressure Globe Stop Valves and Gate Valves for Power Station
DL 612—1996 Supervision Code for Boiler and Pressure Vessel of the Power Industry
DL/T 616—2006 Maintenance &Adjusting Guide for the Thermal Power Plant Steam-Water Piping and Support-Hangers
DL 647—2004 Inspection Code for Boiler and Pressure Vessel in Thermal Power Plant
DL/T 654 The Technical Guide for the Life Assessment of Units in Fossil-Fuel Power Plant
DL/T 674—1999 The Gradational Standard of Spherular Pearlite for Carbon Steel No.20 Used in Fossil Power Plant
DL/T 695—1999 Steel Pipe Butt Welding Fittings for Power Plant
DL/T 714 Technical Guide for the Ultrasonic Testing of Turbine -- Blades
DL/T 715 Selection Guidelines for the Metallic Material of Fossil -- Fired Power Plants
DL/T 717 Technical Guide for the Nondestructive Testing of Turbine-Generator Rotor Bores
DL/T 734 Technical Guide of Welding Repair for Boiler Drum in Fossil -- Fired Power Plants
DL/T 752—2001 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 773—2001 Spheroidization Evaluation Standard of 12Cr1MoV Steel Used in Power Plant
DL/T 786—2001 Standard of Inspection and Estimating Carbon Steel Graphitization
DL/T 787—2001 The Gradational Standard of Spherular Pearlite for 15CrMo Steel Used in Fossil Power Plant
DL/T 819 The Code of 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 850—2004 Pipie Fabrication for Power Stations
DL/T 868—2004 The Code of Welding Procedure Qualification
DL/T 869 The Code of Welding for Power Plant
DL/T 884—2004 Power Plant Metallography Inspection and Assessment Guideline
DL/T 922—2005 Guide Rule of Order and Acceptance for General Steel Valves Used in Thermal Power Plant
DL/T 925 Technical Guide for Eddy Current Testing of Turbine-Blades
DL/T 930 Technical Guide of the Ultrasonic Testing of Turbine Nonbore Rotors
DL/T 939—2005 Guide for Boiler Tube Monitoring and Inspection in Fossil Fuel Power Plant
DL/T 940 The Technical Guide for the Life Assessment of Steam Pipe in Fossil Fuel Power Plant
DL/T 991 Spectral Analysis Guideline of Metal for Electrical Power Equipment
DL/T 999—2006 The Gradational Standard of Spheroidizition for 2.25Cr-1Mo Steel Used in Power Plant
JB/T 1611—1993 Technical Specification of the Manufacturing of Boiler Tube
JB/T 3375 Rules for Receiving Acceptance of Materials for Boiler Construction
JB/T 3595—2002 Valves for Power Station-General Requirements
JB/T 4730—2005 Nondestructive Testing of Pressure Equipments
ASTM A335/A335M Standard Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
3 General Provisions
3.1 Purpose of metal technical supervision
Inspection and diagnosis shall be carried out for the parts under supervision to timely comprehend and grasp the quality condition of the metal parts of equipments, prevent problems related to the metallic materials from appearing during the design, manufacture and installation of the unit and prevent the factors (including material aging and performance reduction during operation) from causing various accidents, which thereby will reduce the times and time of unscheduled outage of the unit, improve the reliability of safe operation of equipments and prolong the service life of equipments.
3.2 Tasks of metal technical supervision
a) Do the manufacture, installation and maintenance of various metal parts within the supervision scope, the quality supervision on materials, welding and parts in the renovation of ageing units as well as the test work of metal well.
b) Conduct investigations and cause analysis for the failure of metal parts under supervision, and propose treatment countermeasures.
c) Carry out inspection and judgement on the defects and defect development of equipments by adopting nondestructive testing technique according to the corresponding technical standards, and also propose corresponding technical measures.
d) Check and grasp the surface state, variance in geometric dimension, ageing of metal structure and deterioration of mechanical properties of the parts under supervision during the service process according to the corresponding technical standards, and conduct evaluation on the damage state of materials and propose corresponding technical measures.
e) Carry out service life evaluation on the important metal parts under supervision and the units of overtime service, conduct safety evaluation on the parts containing defects and provide technical basis for the service life management and predictable maintenance of units.
f) Participate in the training and examination of welders.
g) Establish and perfect the archives of metal technical supervision and carry out electronic document management.
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