Standard No.:	JB/T 6440-2025
English Name:	Radiographic testing of steel castings forvalves
Chinese Name:	阀门铸钢件射线检测
Professional Classification:	JB    Professional Standard - Machinery
Source Content Issued by:	MIIT
Issued on:	2025-10-28
Status:	valid
Superseding:	JB/T 6440-2008 Methods of radiographic examination for steel castings valves
Target Language:	English
File Format:	PDF
Word Count:	23000 words
Translation Price(USD):	690.0
Delivery:	via email in 1 business day

JB/T 6440-2025 Radiographic testing of steel castings for valves 1 Scope This document specifies the general requirements, testing implementation, classification of film defects, evaluation methods, acceptance criteria, and testing records and reports of radiographic testing of steel castings for valves. This document is applicable to the X-ray and γ-ray testing of steel castings for valves made of carbon steel, alloy steel, and stainless steel. This document may be used for reference in the radiographic testing of valve castings made of copper and copper alloys, nickel and nickel alloys, titanium and titanium alloys, as well as aluminum and aluminum alloys. 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. GBZ 117 Standard for radiological protection in industrial radiography GB/T 9445 Non-destructive testing - Qualification and certification of NDT personnel GB/T 11533 Standard for logarithmic visual acuity charts GB/T 12604.2 Non-destructive testing - Terminology - Terms used in radiographic testing GB 18871 Basic standards for protection against ionizing radiation and for the safety of radiation sources GB/T 19348.1 Non-destructive testing - Industrial radiographic film - Part 1: Classification of film systems for industrial radiography GB/T 19802 Non-destructive testing - Industrial radiographic illuminators - Minimum requirements GB/T 23901.2 Non-destructive testing - Image quality of radiographs - Part 2 :Determination of the image quality value using step/hole-type image quality indicators GB/T 23910 Non-destructive testing - Metal intensifying screens for radiographic testing JB/T 7902 Non-destructive testing - Specification for wire-type image quality indicators NB/T 47013.1 Nondestructive testing of pressure equipments - Part 1: General requirements 3 Terms and definitions For the purposes of this document, the terms and definitions given in GB/T12604.2 and NB/T47013.1 and the following apply. 3.1 penetrated thickness W nominal thickness of material in the direction of radiography. In multilayer radiography, penetrated thickness is the sum of nominal thickness of penetrated layers of materials 3.2 source-to-object distance f distance between the source and the surface of the inspected part of the object on the source side measured along the center of the ray beam 3.3 focal distance F distance from the source to the film measured along the center of the ray beam 3.4 source size d effective focus size of the source 3.5 film evaluation scope scope on the film that must be observed and evaluated as specified in this document 3.6 defect evaluation size area of a certain size, square or rectangular, set for evaluating the number and density of defects during quality grading evaluation. 3.7 double film technique radiography technology in which a cassette is loaded with two films and three intensifying screens (front, middle, and back screens) for exposure, and the films are observed on a film illuminator by superimposing the two films

Contents Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 General requirements 4.1 Personnel qualification 4.2 Testing process documents 4.3 Safety requirements 4.4 Equipment and apparatus 5 Testing implementation 5.1 Surface requirements and radiographic testing timing 5.2 Selection of radiographic testing technology grade 5.3 Ray energy 5.4 Source-to-object distance 5.5 Exposure 5.6 Exposure curve 5.7 Radiography arrangement 5.8 Application of image quality indicator (IQI) 5.9 Shielding of unwanted and scattered rays 5.10 Marking 5.11 Film processing 5.12 Requirements for film evaluation 5.13 Film quality 5.14 Film storage 6 Classification of film defects and evaluation methods 6.1 Defect classification and dimension measurement 6.2 Defect grades for gas pores, sand and slag inclusions 6.3 Defect grade for shrinkage cavity 6.4 Comprehensive rating of defects 7 Acceptance criteria 8 Inspection records and reports Annex A (Normative) Main characteristic indicators of the industrial radiographic film Annex B (Informative) Periodic calibration method for nigrometer (optical density meter) Annex C (Normative) Method for determining the source-to-object surface distance Annex D (Normative) Calculation method of focal size Annex E (Normative) Key areas for radiographic testing of valve castings Annex F (Informative) Types and specifications of dedicated image quality indicators Annex G (normative) Placement position of positioning markers