4. Materials
4.1 General requirements for materials
4.1.1 The requirements for materials used in repairs are in general the same as the requirements for materials specified in the Classification Society’s rules for new constructions, (ref. 5).
4.1.2 Replacement material is in general to be of the same grade as the original approved material. Alternatively, material grades complying with recognised national or international standards may be accepted by the Classification Societies provided such standards give equivalence to the requirements of the original grade or are agreed by the Classification Society. For assessment of equivalency between steel grades, the general requirements and guidelines in Section 4.2 apply.
4.1.3 Higher tensile steel is not to be replaced by steel of a lesser strength unless specially approved by the Classification Society.
4.1.4 Normal and higher strength hull structural steels are to be manufactured at works approved by the Classification Society for the type and grade being supplied.
4.1.5 Materials used in repairs are to be certified by the Classification Society applying the procedures and requirements in the rules for new constructions. In special cases, and normally limited to small quantities, materials may be accepted on the basis of alternative procedures for verification of the material’s properties. Such procedures are subject to agreement by the Classification Society in each separate case.
4.2 Equivalency of material grades
4.2.1 Assessment of equivalency between material grades should at least include the following aspects;
- heat treatment/delivery condition
- chemical composition
- mechanical properties
- tolerances
4.2.2 When assessing the equivalence between grades of normal or higher strength hull structural steels up to and including grade E40 in thickness limited to 50 mm, the general requirements in Table 4.1 apply.
4.2.3 Guidance on selection of steel grades to certain recognised standards equivalent to hull structural steel grades specified in Classification Societies’ rules is given in Table 4.2
đang được dịch, vui lòng đợi..
![](//viimg.ilovetranslation.com/pic/loading_3.gif?v=b9814dd30c1d7c59_8619)