CCS DH620 (D620) Steel Plate – Properties & Equivalents

CCS DH620 (also written CCS D620, CCS/D620, CCS Grade D620 or DH620 steel plate) is a high-strength steel for welded marine and offshore structures certified by the China Classification Society (CCS) to CCS Rules for Materials and Welding (2024), Part 1, Chapter 3, Section 4 (High Strength Steels for Welded Structures). The number 620 is the minimum yield strength in MPa (up to 50 mm), tensile strength is 700–890 MPa, and the letter D sets the Charpy V-notch test temperature of −20°C. It is delivered thermo-mechanically rolled (TM) or quenched and tempered (QT) and corresponds to grade DH620 in IACS UR W16.

Gangsteel, a steel plate exporter, supplies CCS DH620 plate with CCS class certificates; the requirements below are taken directly from the current CCS rules.

Related CCS grades: CCS AH620 steel plate, CCS EH620 steel plate, CCS FH620 steel plate, CCS DH550 steel plate, CCS DH690 steel plate.

CCS DH620 chemical composition

Source: CCS Rules for Materials and Welding (2024), Part 1, Chapter 3, Table 3.4.3.2 (same values as IACS UR W16 Rev.3). Notes: Nb+V+Ti ≤ 0.26% and Mo+Cr ≤ 0.65% (not applicable to QT); total Al/N ≥ 2:1 unless other nitrogen-binding elements are used; Ni above 2.00% may be approved by CCS; boron, if added, ≤ 0.005%. CCS specifies the chemical composition as a heat (ladle) analysis only; the Rules give no product (check) analysis tolerances for these plates, so no product-analysis column is shown. If a product analysis is required, agree the tolerances in the order.

CCS DH620 mechanical properties and impact test

Source: CCS Rules for Materials and Welding (2024), Part 1, Chapter 3, Table 3.4.7.4. Plates over 600 mm wide are impact tested transversely (T value applies). For N/NR and TM plates one impact test is taken from each piece; for QT plates from each individually heat-treated piece. Above 50 mm, impact specimens are taken at t/4 and t/2.

Table 3.4.3.4. Ceq = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15; CET = C + (Mn + Mo)/10 + (Cr + Cu)/20 + Ni/40 (H460 and above, at the mill’s option); Pcm may be used for TM and QT steels with C ≤ 0.12%. n/a = not applicable.

CCS DH620 thickness range and delivery condition

Table 3.4.6.2. Thicker plates (N over 250 mm, QT over 150 mm) need special consideration by CCS. Yield and tensile requirements fall in steps above 50 mm and 100 mm, as shown in the table above.

CCS DH620 equivalent grades

The IACS member societies use the same unified requirements, so these grades match in chemistry and properties. A plate still needs the certificate of the vessel’s own class society; one plate can carry dual or multiple class certification only when each society’s surveyor witnesses the tests.

CCS DH620 FAQ

Is CCS D620 the same as CCS DH620?

Yes. CCS lists the grade as DH620; D620 is a common shorthand for the same steel.

What is the yield strength of CCS DH620?

Minimum 620 MPa up to 50 mm, 580 MPa for 50–100 mm and 560 MPa for 100–250 mm. Tensile strength is 700–890 MPa (up to 100 mm).

What is the impact test temperature of CCS DH620?

−20°C, with a minimum average of 41 J transverse or 62 J longitudinal.

What is CCS DH620 equivalent to?

DH620 in IACS UR W16, ABS AB/DQ63, DNV VL D620 and LR DH62. ASTM A131 has no grade at this strength.

How is CCS DH620 supplied?

TM (including TM with accelerated cooling or direct quenching and tempering) or QT. The chemistry and carbon-equivalent limits depend on the delivery condition.

What is the maximum thickness of CCS DH620 plate?

Up to 150 mm in TM or QT condition; thicker plates need special consideration by CCS.

What is the CEV of CCS DH620?

Ceq maximum for plates up to 50 mm is 0.50% (TM), 0.56% (QT). Higher limits apply to thicker plates.

What is the difference between CCS DH620 and the A, D, E and F grades of the same strength?

The strength requirements are identical; only the Charpy test temperature changes (0, −20, −40 or −60°C), and E/F grades have tighter P and S limits.

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Related steel grades: CCS/D420,CCS/A620,CCS/690,CCS/A550

LR equivalent: LR DH62 steel plate