BV船级社规范

NR 216

Chapter 5

WELDING

S ECTION1G ENERAL R EQUIREMENTS

S ECTION2A PPROVAL OF W ELDING C ONSUMABLES

S ECTION3A PPROVAL OF O VER W ELDABLE S HOP P RIMERS

S ECTION4A PPROVAL OF W ELDING P ROCEDURES

S ECTION5A PPROVAL OF CO2 L ASER W ELDING P ROCEDURES

NR 216, Ch 5, Sec 1 SECTION 1G ENERAL R EQUIREMENTS

1Scope

1.1General

1.1.1 This Section specifies the general requirements for fabrication by welding, and the other Sections of the Chap-ter concern the requirements for approval of welding con-sumables ( Sec 2), over weldable shop primers ( Sec 3) and welding procedures ( Sec 4 and Sec 5).

1.1.2 The requirements are essentially intended for the welding of weldable steels and aluminium alloy grades cov-ered by the applicable Articles of these Rules.

1.1.3 Different materials, applications and procedures, as well as other standards and specifications, may be consid-ered by the Society on a case-by-case basis.

2Fabrication by welding

2.1General

2.1.1 Fabrication by welding is to be carried out in compli-ance with the applicable Society Rules and according to normal good practice, general or specific to the individual processes, to the Surveyor’s satisfaction; in particular the conditions stated at the time of approval and authorisation for the use of individual processes are to be complied with. The welded structures, the relevant details and the size of welds are to comply with the applicable requirements; any other requirements indicated on the approved plans or specified during survey of construction are also to be com-plied with.

2.2Approval

2.2.1 Plans

The constructional plans are to be submitted for approval when required by the Rules or in individual cases and are to contain the necessary data relevant to the fabrication by welding of the structures and items represented. In particu-lar, material types, welding details, welding processes and weld size are to be indicated; any details not represented in the plans are, in any case, to comply with the applicable requirements.

2.2.2 Welding procedures and consumables Welding to be used in hull construction, machinery, pres-sure systems and equipment subject to the inspection of the Society, is to be carried out with approved welding consum-ables and in accordance with approved welding proce-dures. 2.2.3 Welders and welding operators

Welders for manual welding and for semiautomatic welding processes are to be properly trained and are to be certified by the Society, as required in the individual applications, unless otherwise agreed.

Welders are to be certified according to the procedures given in the document NR476 “Approval testing of weld-ers”, except for offshore applications where the Society’s Rule Note “Construction survey of steel structures of off-shore units and installations” referenced NR426 DTO R00 E dated May 1992 is to be used.

The certification is to be in due course of validity. Personnel manning the automatic welding machines are to be competent and sufficiently trained.

2.2.4 Welding supervision

Welders are to be supervised and assisted, in the course of the welding operation, by an adequate number of compe-tent supervisors, such as to ensure efficient control of the welding production.

Certification of the welding inspectors is not compulsory and is left to the discretion of the Manufacturer, except in particular cases where it may be required by the Society. 2.2.5 NDT operators

Non-destructive tests are to be carried out by qualified per-sonnel certified by the Society or by recognised bodies in compliance with appropriate standards.

The qualifications are to be appropriate to the particular application.

2.3Welding procedures

2.3.1 Approval of consumables

Consumables are to be approved in accordance with the provisions of Sec 2.

Requirements for approval of welding procedures, where non-approved welding consumables are allowed to be used, are given in Sec 4.

2.3.2 Choice of consumables

Requirements regarding the use of the various grades of approved consumables are indicated in the parts of the Rules concerning the application or at the time of plan approval.

In the case of consumables approved for Mo and Cr-Mo weldable steels, the choice of the grade of the consumables is to be made such that the nominal chemical composition of the deposited metal corresponds to that of the base mate-rial; where electrodes are used, they are to be of the basic covered low hydrogen type.