Section 4 Requirements for welded construction
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 1 Ship Structures - Part 6 Hull Construction in Steel - Chapter 6 Material and Welding Requirements - Section 4 Requirements for welded construction

Section 4 Requirements for welded construction

Parent topic: Chapter 6 Material and Welding Requirements

4.1 General

4.1.1 The requirements of this Section are applicable to grades of steel welded using electric arc welding processes. Where it is proposed to use alternative welding processes, details are to be submitted for approval, prior to the start of fabrication.

4.1.2 Symbols are defined as necessary in each Section.

4.1.3 Ships with enhanced shock notation are to additionally comply with the requirements of Vol 1, Pt 4, Ch 2 Military Load Specification

4.2 Information to be submitted

4.2.1 The plans and information submitted for approval are clearly to indicate details of the welded connections of the main structural members, including the type, disposition and size of welds. This requirement includes welded connections to steel castings.

4.2.2  The information to be submitted should include the following:

  1. Whether weld sizes given are throat thicknesses or leg lengths.

  2. Grades and thicknesses of materials to be welded.

  3. Location, types of joints and angles of abutting members.

  4. Reference to welding procedures to be used.

  5. Sequence of welding of assemblies and joining up of assemblies.

4.3 Welding equipment

4.3.1 Welding plant and equipment are to be in accordance with the requirements specified in Ch 13, 1.8 Welding equipment and welding consumables of the Rules for Materials.

4.4 Welding consumables

4.4.1 The requirements for welding consumables are to be in accordance with the requirements specified in Ch 13, 1.8 Welding equipment and welding consumables of the Rules for Materials.

4.4.2 The approval of welding consumables is to be in accordance with Ch 11 Approval of Welding Consumables of the Rules for Materials.

4.5 Welding procedures

4.5.1 Welding procedures are to be established for the welding of all joints in accordance with the requirements specified in Ch 13, 1.9 Welding procedure and welder qualifications of the Rules for Materials.

4.5.2 All welding procedures are to be tested and qualified in accordance with the requirements of Ch 12 Welding Qualifications of the Rules for Materials and are to be approved by the Surveyor prior to construction.

4.5.3 Welders and welding operators are to be proficient in the type of work to be undertaken and are to be qualified in accordance with the requirements specified in Ch 12 Welding Qualifications of the Rules for Materials.

4.6 Inspection of welds

4.6.1 Effective arrangements are to be provided by the Shipbuilder for the inspection of all finished welds in order to ensure that all welding has been satisfactorily completed.

4.6.2 All finished welds are to be subjected to non-destructive examination in accordance with the requirements specified in Ch 13, 2.12 Non-destructive examination of steel welds of the Rules for the Manufacture, Testing and Certification of Materials, July 2022 , and the general NDE requirements as per Ch 1, 5.1 General NDE requirements of the Rules for the Manufacture, Testing and Certification of Materials, July 2022. Details of weld defect levels are given in the Naval Survey Guidance for Steel Ships.

4.6.3 Typical locations for volumetric examination and number of checkpoints to be taken are as shown in Table 6.4.1 Recommended extent of NDE checkpoints. A list of the proposed items to be examined is to be submitted for approval.

Table 6.4.1 Recommended extent of NDE checkpoints

Volumetric non-destructive examinations – recommended extent of testing, see Ch 13, 2.12 Non-destructive examination of steel welds 2.12.12
Item Location Checkpoints (see Note 1)
Intersections of butts and seams of fabrication and section welds Throughout:  
(a) The hull envelope plating:  
  • at critical locations identified by FDA, see Note 2
All
  • at other highly stressed areas, see Note 3
All
  • remainder
 1 in 2
(b) longitudinal and transverse bulkheads 1 in 2
(c) inner bottom 1 in 2
Butt welds in plating Throughout 1 m in 25 m (see Notes 4 and 5)
Seam welds in plating Throughout 1 m in 100 m
Butts in longitudinals Hull envelope within 0,4L amidships 1 in 10 welds
Hull envelope outside 0,4L amidships 1 in 20 welds
Bilge keel butts Throughout 1 in 10 welds
Structural items when made with full penetration welding as follows: sheerstrake to deck stringer plate or angle Throughout 1 m in 20 m

Note 1. The length of each checkpoint is to be between 0,3 m and 0,5 m.

Note 2. FDA signifies the fatigue design assessment procedure.

Note 3. Typically those at shear strake, deck stringer, keel strake and turn of bilge.

Note 4. Checkpoints in butt welds and seam welds are in addition to those at intersections.

Note 5. Welds at inserts used to close openings in hull envelope plating are to be checked by non-destructive examination.

Note 6. Agreed locations are not to be indicated on the blocks prior to the welding taking place, nor is any special treatment to be given at these locations.

Note 7. Particular attention is to be given to repair rates in longitudinal butts. Additional welds are to be tested in the event that defects such as lack of fusion or incomplete penetration are repeatedly observed.

4.6.4 For the items butt and seam welds in plating, shown in Table 6.4.1 Recommended extent of NDE checkpoints, consideration may be given for a reduction in inspection frequency for welds where volumetric inspection and the quality assurance techniques applied indicate satisfactory quality.

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