Detail of DL/T 820-2002

Introduction of DL/T 820-2002

1 Scope 1.1 This standard specifies the ultrasonic inspection method and test result grade assessment of pipe welded joint. 1.2 This standard is applicable to manual A-mode ultrasonic inspection using pulse-echo technique for welded joints of one-side welded and both-side formed medium-thick-wall pipe, medium-small-diameter thinwalled pipe and Austenitic medium-small-diameter thinwalled pipe which are used as pressure pipe made of ferritic steel in equipment fabrication and installation and overhaul in power industry. a) Medium-thick-wall pipe: external diameter is greater than or equal to 108 mm; wall thickness is greater than or equal to 14mm and less than or equal to 160 mm. b) Medium-small-diameter thinwalled pipe: external diameter is greater than or equal to 32mm and less than or equal to 159mm; wall thickness is greater than or equal to 4mm and less than 14mm. c) Austenitic medium-small-diameter thinwalled pipe: external diameter is greater than or equal to 32mm and less than or equal to 159mm; wall thickness is greater than or equal to 4mm and less than or equal to 8mm. 1.3 This standard is not applicable to ultrasonic inspection for welded joints of coarse grained materials like cast steel, austenitic stainless steel with wall thickness greater than 8mm, etc., longitudinal welded joints of medium-thick-wall pipe with diameter ratio less than 80% and welded joints of Austenitic and Pearlitic dissimilar steels. 2 Normative References The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. GB 11345-1989 Method for Manual Ultrasonic Testing and Classification of Testing Results for Ferritic Steel Welds GB/T 12604.1-1990 Terminology for Nondestructive Testing - Ultrasonic Testing DL 5007-1992 The Code of Election and Acceptance for Power Plant Construction - Welding Section DL/T 675-1999 Examination Code for Qualification of Non-destructive Testing Personnel of Electric Power Industry DL 5009.1-1992 Code of safety operation in power engineering construction - Thermal Power Plant JB/T 9214-1999 Practice for Evaluating Performance Characteristics of A Scope Ultrasonic Pulse-echo Testing Systems JB/T 10061-1999 Commonly Used Specification for A-mode Ultrasonic Flaw Detector Using Pulse-echo Technique JB/T 10062-1999 Testing Methods for Performance of Probes Used in Ultrasonic Flaw Detection JB/T 10063-1999 Specification for No.1 Standard Test Block Used in Ultrasonic Flaw Detection JB 4730-1994 Nondestructive Testing of Pressure Vessels

Contents of DL/T 820-2002

Foreword i 1 Scope 2 Normative References 3 Terms 4 General Requirements 5 Inspection on Welded Joint of Medium-thick-wall Pipe 6 Inspection for Welded Joint of Medium-small-diameter Thinwalled Pipe 7 Inspection for Welded Joint of Austenitic Medium-small-diameter Thinwalled Pipe Annex A (Normative) Portable Test Block Annex B (Normative) Reference Test Block for the Root Defect of Welded Joints Annex C (Normative) Longitudinal Transverse Wave Tandem Scan Inspection Method Annex D (Normative) Drawing of Distance-Amplitude Curve (DAC) Annex E (Normative) Compensation Amount Measurement Annex F (Normative) Special Test Block Dl-1 for the Ultrasonic Inspection of Welded Joints of Small Diameter Pipe Annex G (Normative) Method and Requirements for Probe Grinding Annex H (Normative) Determination of Probe Parameters and Performance for Medium-Small-Diameter Thin Walled Pipe Annex I (Normative) Adjustment of Time Base Line Scanning for Medium-Small-Diameter Thin Walled Pipe Annex J (Informative) Analysis of Reflection Echo