What CCS Approval on a Marine Plate Means
The China Classification Society, known as CCS, is one of the classification societies that approve steel works and steel products for shipbuilding and offshore construction. A plate described as CCS marine plate is therefore not a special steel grade in itself; it is an ordinary shipbuilding grade, such as a normal strength grade A, B, D or E plate or a higher strength AH, DH or EH grade, that has been produced by a works approved by CCS and tested against the society's rules. The value of the marking is traceability: it tells the surveyor and the buyer that the plate belongs to a heat whose tests were witnessed or accepted by the society.
Marking and Stamping to Look For
Approved plates carry an identifying mark that must survive handling and fabrication. Typical items to inspect are:
The society's brand and the steel grade designation, applied by stamping or by approved paint marking, normally at one end of the plate.
The manufacturer's name or works identification.
The heat number and plate number, which link the plate to a specific test result.
Order number or contract reference where the order specifies one.
Thickness, and where relevant the delivered condition such as normalised or controlled rolled.
A stamp that is blurred, incomplete, or that appears only on the packing list and not on the plate itself, is a first warning sign. Marking is required to remain legible after delivery, and a supplier who cannot point to the stamp on the physical plate is usually unable to demonstrate the test chain behind it.
Checking the Inspection Certificate
The certificate is the second half of the evidence, and it must agree with the stamp. Read it for the following:
| Item on certificate | What it has to show |
|---|---|
| Heat number and plate number | Identical to the marking on the plate |
| Steel grade | Grade and, for higher strength steel, the strength class |
| Chemical composition | Ladle and, where required, product analysis within the limits for the grade |
| Mechanical tests | Tensile result against the grade requirement and Charpy impact energy at the grade test temperature |
| Certificate type | Issued in the inspection-document form required by the order |
| Society endorsement | Confirmation that the tests were carried out under the approved scheme |
Higher strength shipbuilding grades carry their impact class in the letter that precedes the strength class: DH plate is tested at −20 °C and EH plate at −40 °C, while A and B normal strength grades are tested at 0 °C. If the certificate shows an impact test at the wrong temperature for the ordered grade, the certificate does not cover what was ordered.
Verifying Grade and Fit for the Intended Structure
Before accepting a lot, match the ordered grade against the intended use: hull plating, deck plating, internal bulkheads and structural members each carry different grade and thickness requirements set by the society's rules and by the ship's design. Confirm that the delivered thickness corresponds to the approved thickness range for that grade, because impact requirements for higher strength steel change with thickness. Where the plate is to be used for a structural detail under survey, the surveyor will expect the certificate chain to run unbroken from the steel works to the fabricated item.
Physical Inspection before Acceptance
Measure thickness and check it against the ordered tolerance, particularly on plates that have been handled and stacked roughly.
Look for delamination, seams, laminations and surface cracks on the cut edges; ultrasonic testing is the reliable check when internal soundness is in doubt.
Check flatness and edge condition, and record any transit damage before signing the delivery note.
Confirm that the heat number stamped on the plate matches the certificate for that individual plate and not only for the lot.
Frequently Asked Questions
Q: Is CCS marine plate a special steel grade?
A: No. It is a standard shipbuilding grade, such as A, B, D, E, AH or DH, produced and tested under the China Classification Society's approval scheme.
Q: What identifies an official CCS plate?
A: The society's brand together with the grade, the works identification, the heat number and the plate number marked on the plate itself, matching the inspection certificate.
Q: How can the grade be confirmed?
A: By reading the grade designation in the marking and checking the mechanical test results on the certificate against the requirements for that grade and thickness.
Q: What impact test temperature applies to DH and EH plate?
A: DH grades are tested at −20 °C and EH grades at −40 °C; normal strength A and B grades are tested at 0 °C.
Q: Is the certificate alone sufficient proof?
A: No. The certificate must be traceable to the marking on the delivered plate; without that link the tested material cannot be shown to be the material supplied.
Q: What is checked at delivery?
A: Grade marking, heat number, thickness against tolerance, flatness, edge condition and any surface or internal defects, with ultrasonic testing where internal soundness is required.
