RULES DET NORSKE VERITAS (DNV) = STRUCTURES = - Boat Design Net

Amended July 2011, see page 3 Rules for High Speed, Light Craft and Naval Surface Craft, January 2011Pt.3 Ch.3 Sec.2 – Page 15SECTION 2MATERIALS AND MATERIAL PROTECTIONA. GeneralA 100 Application101 The rules in this chapter apply to wrought aluminium alloys for objects classified or intended forclassification with the Society.A 200 Material certificates201 Rolled and extruded wrought aluminium alloys, glass reinforced plastic and core materials for hullstructures and rolled steel are normally to be supplied with DNV material certificates.202 For class certificate requirement for chemical composition, mechanical properties, heat treatment andrepair of defects, see Pt.2 Ch.2.203 Particular attention is to be given to aluminium hull materials specification in Pt.2 Ch.2.204 Requirements for material certificates for forgings, castings and other materials for special parts andequipment are stated in connection with the rule requirements for each individual part.B. Structural Aluminium AlloyB 100 General101 Aluminium alloy for marine use may be applied in hulls, superstructures, deckhouses, hatch covers andsundry items.B 200 Aluminium grades201 Aluminium alloys are to have a satisfactory resistance to corrosion in marine environments. Grades forwelded structures are to be weldable, applying one of the welding methods approved by the Society.202 For major hull structural components, alloys with temper H116/H321 for rolled products, and alloys withtemper T5/T6 for extruded products, are normally to be used. The use of 0- or F temper must be agreed withthe Society.203 The use of 6000 series aluminium alloys in direct contact with sea water may be restricted depending onapplication and corrosion protection system. The use of these alloys are to be agreed with the Society.204 In weld zones (HAZ) of rolled or extruded products, the factor f 1 given in Table B4 may in general beused as basis for the scantling requirements.205 Welding consumables are to be chosen according to Table C2 in Pt.2 Ch.3 Sec.2. The consumable chosenare to have minimum mechanical properties not less than specified for the parent alloy in the welded condition.B 300 Chemical composition301 The chemical composition is to satisfy the requirements in Pt.2 Ch.2. Other alloys or alloys which do notfully comply with Pt.2 Ch.2, may be accepted by the Society after consideration in each particular case. Specialtests and/or other relevant information, e.g. which confirm a satisfactory corrosion resistance and weldability,may be required.B 400 Mechanical properties401 Requirements to mechanical properties for different delivery conditions are given in Tables B1 and B2for wrought products, extruded products and rivet bars/-rivets, respectively. Other delivery conditions withrelated mechanical properties may be accepted by the Society after consideration in each particular case.Table B1 Factor f 1 for wrought aluminium alloy sheets, strips and plates, t: 2 mm ≤ t ≤ 40 mmDNV Designation Temper f 1NV-5052H32H340.610.69NV-5154A 0, H111 0.35NV-5754 H24 0.69NV-5454H32H340.730.79DET NORSKE VERITAS AS