Section 2 Materials

2.1.1 The Rules for Naval Ships state that ‘Materials are to be made at works which have been approved by the Committee for the type of product being supplied’. It is the building port Surveyor’s responsibility to ensure that a Builder is aware of this requirement and verify that it is complied with. Approved Works are detailed in the Lists of Approved Manufacturers of Materials and Recognized Proving Establishments.

2.2.1 The need to ensure that all structural material for classed ships is certified by the Surveyors in accordance with LR’s requirements should be impressed on Builders at the design stage, and it should be checked that test certificates or shipping statements in accordance with LR’s Rules are furnished by the steel manufacturers when the material is delivered. It is appreciated that Surveyors in the building yards cannot see and check every piece of material from its arrival at the stockyard through to erection, but they must satisfy themselves by random checks that the yard system is adequate in this respect. When material is shot-blasted and primed on reception, the steelwork’s identification marks should be clearly marked with the appropriate colour code. This checking of material with the test certificates should be done at the earliest possible stage in order to prevent the use of material which has not been properly tested and verified at the steelworks. These certificates also afford an early opportunity to verify that material is being supplied to the approved scantlings.

2.3.1 Surface inspection is the responsibility of the steelmaker and the Surveyor at the steelworks does not normally undertake this work unless it is particularly specified. Where defects are found after delivery to the Builder, any rectification should be agreed and should generally be in accordance with the Rules for Materials.

2.3.2 The limits of depth and extent of rounded surface defects on plate, cast or forged material in relation to the material plate thickness are shown in Table 3.2.1 .

2.3.3 Defects are to be made good by grinding only, subject to the plate thickness not being reduced by more than seven per cent of the nominal thickness or 3 mm, whichever is the lower, and the area involved not exceeding two per cent of the surface area.

2.3.4 When the limits in Table 3.2.1 are exceeded, plates are to be made good by grinding followed by welding.

2.3.5 Where the depth of the deepest imperfection exceeds 20 per cent of the nominal thickness, or the defective area exceeds two per cent of the total surface area, such areas are to be cropped and replaced, or the material rejected.

2.3.6 Complete removal of the defects is to be verified by suitable non-destructive examination techniques and after welding repair is to be proved free from further defects.

2.3.7 Care is to be taken in the repair of defects in higher tensile steel. Low hydrogen electrodes with similar properties to the higher tensile steel are to be used with preheating as necessary.

2.3.8 Plates in which laminations are suspected or detected are to be ultrasonically tested to determine the full extent of such laminations. Areas of lamination are to be removed.

2.3.9 Defective plate, with defects in excess of those stated, is to be cropped back and replaced or material rejected.

2.4.1 When defects exceed the limits shown below, the portion of the plate affected is to be cropped and replaced. Plate inserts are to be arranged in accordance with Table 3.2.1 Part replacement of plates and the alignment of inserts is to be in accordance with Table 3.2.1 Part replacement of plates.

Table 3.2.1 Part replacement of plates

A x B	Parts to be replaced	Strength members	Elsewhere
	End and corner of plate	300 x 1000	300 x 300
	Side of plate	300 x 300	300 x 300
	Insert	300 x 300	300 x 300
C	Circular insert	dia. 300	dia. 150
Line of plate replacement to be not less than 100 from extreme edge of defect. All dimensions are in mm. Weld sequence given by figure (1)
Note 1. All dimensions are minimum. Note 2. Rolling direction of replaced plate to be the same as that of the parent plate. Note 3. Minimum distance from outermost defect to line of weld – 100 mm.		Note 4. Dimensions in millimetres: r = 12%B, 5t or 75 mm whichever is the greater. Note 5. Stiffener web butt weld scallop to be filled on final pass (4). Note 6. Insert welds are not to be within 75 mm of butts, seams, internal structure or other inserts.

2.5.1 All large or important forgings, castings and prefabrications, such as sternframes, rudders, rudderstocks, rudder axles, quadrants or tillers, require to be examined and tested in accordance with the Rules for Materials by the Surveyor attending the manufacturer’s works. Procedures for the identification and certification of all such items (excluding prefabrications) are detailed in the Rules for Materials and the Surveyors at the building yard should ensure that they receive appropriate certificates for the items intended for the vessel building under their survey. The markings on the items should be checked against the certificates.

2.5.2 When, at the manufacturer’s request, limitations have been agreed upon the extent of Non-Destructive Examination (NDE) carried out on an item in a semi-finished, rough machined, or part machined condition, the Surveyor at the manufacturers will have made a statement to this effect on the certificate for the item. When work is subsequently carried out upon such an item at the shipyard, the Surveyor at the building port should consider further NDE. Where further NDE is carried out on the item, this should be indicated on its final certificate.

2.6.1 The surface cleanliness of the materials in preparation for painting is to be in accordance with national or paint manufacturer’s standards.

2.6.2 Where approved corrosion control coatings are to be used, the quality of surface treatment is to be in accordance with the grade specified in the approval documents.

2.7.1 All welding consumables are to be approved in accordance with the requirements of the Rules for Materials, and selected from the List of Approved Welding Consumables for use in Ship Construction.

2.7.2 Surveyors should satisfy themselves that all storage spaces provided by the Builder will maintain welding consumables in good condition. They should also ensure satisfactory arrangements for their maintenance after issue to the work force, and for compliance with manufacturer’s instructions regarding use of their product. Systematic checks should be made on the consumables being used, having regard to the grades of steel and welding positions involved.

2.8.1 The extent of NDE required during new construction is to be in accordance with Vol 1, Pt 6, Ch 6, 4 Requirements for welded construction of the Rules for Naval Ships.

2.8.2 Acceptance criteria are given in Table 3.2.2 Weld defect acceptance levels for fabrication.