R D51|KR D51 STEEL PLATE

KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield) is a extra-high-strength shipbuilding / offshore hull plate grade under KR Rules Pt 2; IACS UR W16 H500 / DH500 practice. This specification page covers grade identity, chemistry, mechanical requirements, related grades, and RFQ practice. Accept material against the ordered edition and the mill test certificate.

Grade Identity and Delivery Condition

KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield) is supplied for projects that name this designation on the purchase order or calculation sheet. Standard delivery condition is TM or QT per KR-approved mill route; D quality impact at -20 deg C. Gangsteel supplies export plate and related products with EN 10204 documentation. Do not accept an alternate heat-treatment route unless a written concession changes the specification requirement.

Chemical Composition - Heat Analysis (KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield))

EHS chemistry is delivery-condition and mill-approval dependent under UR W16 / KR Pt 2. Values are the rule envelope - exact ladle limits on the KR-endorsed MTC govern. Ceq/CET/Pcm report as required.

Element / rule	Requirement
C, max	0.21 (TM/QT routes often tighter, e.g. 0.14-0.20)
Si, max	0.55 (QT may allow ~0.80 per approval)
Mn, max	1.70
P, max	0.025
S, max	0.025
Al (acid soluble), min	0.015 (or total Al ~0.020)
Nb / V / Ti	microalloy per approved route (combined caps apply)
Cu / Cr / Ni / Mo / B / N	per KR / mill approval sheet

Mechanical Properties (KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield))

Confirm thickness, specimen orientation, and any supplementary impact, UT, or hardness requirements on the PO.

Property	Requirement
Yield ReH, min	500 MPa
Tensile Rm	610-770 MPa
Elongation A, min	16%
Impact (D quality, -20 deg C)	~50 J long / 33 J trans average (confirm MTC)
Delivery	TM or QT per KR approval

Related / Near-Equivalent Grades

Near-equivalents are for cross-reference only. They are not automatic code substitutes. Substitution requires engineer approval and matching certificate scope.

System	Grade	Note
IACS	DH500 / H500	Unified 500 MPa EHS band
ABS	DH50 / DQ51	Sister society
DNV / CCS / NK	DH500 / KD500	Sister society names

Frequently Asked Questions

What is KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield)?

KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield) is a extra-high-strength shipbuilding / offshore hull plate under KR Rules Pt 2; IACS UR W16 H500 / DH500 practice. It is ordered when drawings or the calculation sheet name this designation specifically.

What chemical composition applies to KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield)?

Controlled elements and limits are tabulated above from the governing standard. Always verify the heat analysis on the MTC against the ordered edition.

What mechanical properties should buyers expect for KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield)?

Tensile, yield, elongation, and related limits are tabulated above. Design allowables must come from the applicable pressure-vessel or structural code, not from a web summary.

What delivery condition is required for KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield)?

Standard delivery is TM or QT per KR-approved mill route; D quality impact at -20 deg C. State it explicitly on the PO. Do not accept an alternate route without a written concession.

How does KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield) differ from near-equivalent grades?

Near-equivalents may differ in carbon or alloy bands, tensile class, impact temperature, or heat treatment. Substitution needs engineering approval and matching certificate scope.

How do I RFQ KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield) from Gangsteel?

Send KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield), thickness x width x length, quantity or tonnage, delivery condition, optional impact/UT/Z tests, EN 10204 3.1 or 3.2, destination, and any dual-mark needs. Gangsteel replies with mill options, lead time, and packing notes.

Ordering and Mill Certificates

State grade KR Grade RD51 / D51 (IACS UR W16 extra-high-strength ~500 MPa yield), dimensions, quantity, delivery condition, optional NDT/PMI, and certificate (EN 10204 3.1 standard; 3.2 when third-party inspection is ordered). Gangsteel supplies export plate and related products with mill test certificates. Contact Gangsteel for stock and mill production RFQs.