Standard No.:	QJ 1842A-2011
English Name:	Technical requirements of structural steel and stainless steel fusion welding
Chinese Name:	结构钢、不锈钢熔焊技术要求
Professional Classification:	QJ    Professional Standard - Aerospace
Issued on:	2011-07-19
Implemented on:	2011-10-1
Status:	valid
Superseding:	QJ 1842-1995 Technical Specification for Fusion Welding of Structural Steel and Stainless Steel
Language:	English
File Format:	PDF
Word Count:	5000 words
Price(USD):	300.0
Delivery:	via email in 1 business day

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This standard replaces QJ 1842-1995 Technical conditions for structural steel and stainless steel fusion welding. The following main changes have been made with respect to QJ 1842-1995: ——The clause “Terms and definitions” is added; ——The welding types “plasma arc welding” and “mixed gas welding” are added; ——The relevant requirements for parent metal with thickness no greater than 1mm in the former standard are canceled; ——The requirements for tensile strength of joints are specified in a more accurate way; ——The requirements for values of weld width in the former standard are canceled, and the requirements for uniformity of weld width are increased; ——The relevant welding terms are corrected; ——The concave defects are described in detail; ——The method for counting defects of welds with length less than 100mm is specified; ——The requirements for line, congregational and single defects (porosities, tungsten inclusions, inclusions and slag inclusions) inside joints are further specified; ——The requirements for root reinforcement of T-joints, lap joints and corner joints are canceled; ——The items that cannot be detected by X-ray are specified; ——The method for determining the repair times is defined. This standard was proposed by China Aerospace Science and Technology Corporation. This standard is under the jurisdiction of China Academy of Aerospace Standardization and Product Assurance. This standard was firstly issued in January, 1990 and was firstly revised in January, 1995. Technical requirements of structural steel and stainless steel fusion welding 1 Scope This standard specifies the general requirements for structural steel and stainless steel fusion welding (including manual welding, submerged arc welding, oxy-acetylene welding, carbon dioxide arc welding with thin wire, tungsten argon arc welding, MIG, plasma welding and mixed gas welding), quality grade of joints, quality requirements for joints, and dressing and repair welding of defects, as well as the requirements for joint inspection. This standard is applicable to the design, manufacture and inspection of fusion welded joints of structural steel and stainless steel with parent metal thickness greater than 1.0mm for aerospace products. This standard is not applicable to fusion welding of castings. 2 Normative references The following normative documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, 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 document referred to applies. GB/T 324 Weld symbolic representation on drawings GB/T 2649 Methods of sampling for mechanical properties tests of welded joint GB/T 2651 Tensile test method on welded joints GB/T 3375 Welding terminology GB/T 5185 Welding and allied processes - Nomenclature of processes and reference numbers GJB 481 Welding quality control requirements GJB 1187 Radiographic inspection GJB 2367 Liquid penetrant inspection QJ 1843 Specification for structural steel and stainless steel fusion welding process QJ 3099 General requirements for welding quality control of aerospace products   3 Terms and definitions For the purposes of this standard, the terms and definitions given in GB/T 3375 and the following apply. 3.1 uniformity of weld width difference between the maximum and minimum widths along the same weld 3.2 single defect defect whose distance to the adjacent defect is not less than three times the larger diameter of the two 3.3 line defect defect distributed on a line (straight line or line similar to the contour of weld edge), with a quantity of no less than three, and with the distance among them no greater than three times the larger diameter of any two adjacent defects 3.4 congregational defect defect group with the distance among defects no greater than three times of the larger diameter of any two adjacent defects   4 General requirements 4.1 The joint design shall meet the requirements for structural welding usability specified in QJ 3099, and the requirements for joint and welding technologies shall be marked on the design drawings according to the requirements of GB/T 324, GB/T 5185 and this standard. 4.2 The technicians, operators and inspectors engaged in welding shall meet the relevant requirements in GJB 481. 4.3 Equipment and tooling used for welding shall meet relevant requirements specified in QJ 3099. 4.4 The weldment materials and welding materials shall be provided with qualification certificates and shall be within the validity period. 4.5 The guarantee conditions for welding process shall meet the requirements of QJ 1843. 4.6 The coating and plating of weldments shall be carried out after welding. It shall be specified in the design documents if coating and plating must be carried out before welding. 4.7 In case of any special requirements, they shall be specified in the design documents. 5 Quality requirements for joints 5.1 Quality grade of joints The quality grade of joints is divided into Grades I, II and III according to the requirements of GJB 481. The quality grade of joints shall be determined by the design department after comprehensive evaluation with the process department according to the stress conditions, structural characteristics of weldments, working characteristics, importance, reliability and process feasibility. Grades I and II joints shall be indicated in the design documents, and those not indicated are Grade III joints.  

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 General requirements 5 Quality requirements for joints 6 Dressing and repair welding of defects 7 Requirements for joint inspection