Rolled ferritic steel products
|Publication Date:||1 May 2016|
Scope and application
This programme is applicable for the approval of material manufacturers of:
Rolled ferritic steel products,
as referred in the Society's rules and standards. For a description of general requirements, conditions and procedures related to the approval, please refer to DNVGL CP 0346 which shall be applied in combination with this programme.
This programme is applicable for the approval of manufacturers of products indicated in Table 1 as given in RU SHIP Pt.2, and relevant parts of other applicable DNV GL rules and standards.
The product(s) used for approval testing (see Sec.3) will place limitations on the range of approval. The approval will be limited to:
each steel grade listed below
each product category, see Table 1
each kind of product form (plates, strips/coil, sections, bars etc.)
particular processing route and manufacturing variables
maximum tested thickness or diameter.
Approval of one product form will not cover other product forms (example: round/flat bars will not cover sections). However, approval for one grade of steel may also cover approval of lower strength or toughness grades without additional approval testing. This is based on certain approval principles as given in App.A.
Approval is given to the following typical product categories:
hot rolled structural steels
extra high strength
boilers and pressure vessel steels
carbon and carbon-manganese
steels for low temperature service
fine grained carbon-manganese
bars for anchor chain cables and accessories
carbon and carbon-manganese
Approval is given to the following typical manufacturing variables in processing route:
steelmaking process (BOC, EAF etc.) and secondary refining (LF, VD, VAD or VOD etc.)
deoxidation (killed etc.)
fine grain practice (singly or any combination of Al, Nb, V & Ti)
casting method (CC or IC)
dimensions of starting material
condition of supply (AR, NR, N, TM or QT etc.)
When applicable, approval will be given for the following additional conditions:
steel grades with specified through thickness properties, 'Z' grade (Z25 or Z35). See Sec.3 [2.9]
steel grade(s) of improved weldability, 'W' grade(s) (example VL EW36 etc.)
rolled round bars intended to be machined into components (as a substitute for forged bars) for which requirements reduction ratio, sampling, and acceptance criteria for mechanical properties requirements and NDE/inspection shall be according to RU SHIP Pt.2 Ch.2 Sec.6 Steel forgings. Approval test scope is given in this approval program
steels intended for high heat input welding ≥ 50 kJ/cm shall be specially approved. Approval is given on the approval of manufacturer certificate using a high heat input welding notation, e.g. D32-W200, indicating approval of steel grade D32 for welding by heat input ≤ 200 kJ/cm. See Sec.3 [2.8]
steel plates intended for 'cold formed plating' may be specially approved for applications where cold forming with theoretical deformation exceeding the limits given in RU SHIP Pt.3 Ch.3 Sec.1 [2.7] subject to additional testing (e.g. strain age testing etc.) for which test scope shall be agreed on case by case basis
steel plates with prequalified CTOD properties of GCHAZ after welding. For this case, the manufacturer may apply for special approval to add suffix 'COD' to the approved grades. Test scope and acceptance criteria for COD grades are given in DNVGL CP 0348
selected steel grades according to relevant international standards, for which approval justification and test scope shall be agreed on case by case basis.
Starting material /semi-finished steel products shall be produced at works approved by the Society:
when steel rolling mill operates their own steel making and produce their semi-finished steel products (slabs/ingots/etc.),
when raw materials for steel rolling mill (slabs/ingots/etc.) are not produced at the rolling mill, the semifinished steel products shall be procured from DNV GL approved steelmaker.
The manufacturer's own heat treatment facilities shall be evaluated and approved by the Society, either under this approval programme, or as approved "heat-treatment workshop" based on the approval programme DNVGL CP 0351.
Where heat treatment is performed by a sub supplier, the sub supplier shall be approved by the Society as heat treatment workshop in accordance with DNVGL CP 0351.
Manufactures of specially designed rolled steel products for application in container ships, corrosion resistant steels for cargo oil tanks, structural hollow sections and works carrying out decoiling of strip/coiled products are not covered by this programme, but need separate approval according to following approval programs:
DNVGL CP 0348, Rolled steel products for application in container ships including grades with BCA and COD properties - additional requirements for steel rolling mill, where relevant
DNVGL CP 0429, Corrosion resistant steels for cargo oil tanks
DNVGL CP 0347, Steel hollow sections (including pipes for structural applications)
DNVGL CP 0349, Decoiling workshop.